1
|
Yii F, Strang N, Bernabeu MO, Dhillon B, MacGillivray T. Corneal biomechanics are not exclusively compromised in high myopia. Ophthalmic Physiol Opt 2024; 44:977-986. [PMID: 38563586 DOI: 10.1111/opo.13313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 03/15/2024] [Accepted: 03/22/2024] [Indexed: 04/04/2024]
Abstract
INTRODUCTION Research assuming linearity has concluded that corneal biomechanics are compromised in high myopia. We investigated whether this assumption was appropriate and re-examined these associations across different levels of myopia. METHODS Myopic (spherical equivalent refraction, SER ≤ -0.50 D) eyes of 10,488 adults aged 40-69 years without any history of systemic and ocular conditions were identified in the UK Biobank. Ordinary least squares (OLS) regression was employed to test the linear association between corneal hysteresis (CH) or corneal resistance factor (CRF), separately, and SER while controlling for age, sex, corneal radius and intraocular pressure. Quantile regression (QR) was used to test the same set of associations across 49 equally spaced conditional quantiles of SER. RESULTS In OLS regression, each standard deviation (SD) decrease in CH and CRF was associated with 0.08 D (95% CI: 0.04-0.12; p < 0.001) and 0.10 D (95% CI: 0.04-0.15; p < 0.001) higher myopia, respectively. However, residual analysis indicated that the linearity assumption was violated. QR revealed no evidence of a significant association between CH/CRF and SER in low myopia, but a significant (p < 0.05) positive association became evident from -2.78 D (0.06 and 0.08 D higher myopia per SD decrease in CH and CRF). The magnitude of association increased exponentially with increasing myopia: in the -5.03 D quantile, every SD decrease in CH and CRF was associated with 0.17 D (95% CI: 0.08-0.25; p < 0.001) and 0.21 D (95% CI: 0.10-0.31; p < 0.001) higher myopia. In the -8.63 D quantile, this further increased to 0.54 D (95% CI: 0.33-0.76; p < 0.001) and 0.67 D (95% CI: 0.41-0.93; p < 0.001) higher myopia per SD decrease in CH and CRF. CONCLUSIONS Corneal biomechanics appeared compromised from around -3.00 D. These changes were observed to be exponential with increasing myopia.
Collapse
Affiliation(s)
- Fabian Yii
- Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, UK
- Curle Ophthalmology Laboratory, Institute for Regeneration and Repair, The University of Edinburgh, Edinburgh, UK
| | - Niall Strang
- Department of Vision Sciences, Glasgow Caledonian University, Glasgow, UK
| | - Miguel O Bernabeu
- Centre for Medical Informatics, Usher Institute, The University of Edinburgh, Edinburgh, UK
- The Bayes Centre, The University of Edinburgh, Edinburgh, UK
| | - Baljean Dhillon
- Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, UK
- Curle Ophthalmology Laboratory, Institute for Regeneration and Repair, The University of Edinburgh, Edinburgh, UK
- Princess Alexandra Eye Pavilion, NHS Lothian, Edinburgh, UK
| | - Tom MacGillivray
- Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, UK
- Curle Ophthalmology Laboratory, Institute for Regeneration and Repair, The University of Edinburgh, Edinburgh, UK
| |
Collapse
|
2
|
Wan K, Wolffsohn JS, Cho P. Role of waveform signal parameters in the classification of children as relatively slow and fast myopia progressors. Clin Exp Optom 2024; 107:402-408. [PMID: 36797056 DOI: 10.1080/08164622.2023.2177098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 01/14/2023] [Accepted: 02/01/2023] [Indexed: 02/18/2023] Open
Abstract
CLINICAL RELEVANCE Identification of the baseline chracteristics for children undergoing orthokeratology with relatively fast myopia progression can allow a more accurate determination of the risk/benefit ratio. BACKGROUND This study aimed to investigate if baseline corneal biomechanics can classify relatively slow and fast myopia progression in children. METHODS Children aged six to 12 years with low myopia (0.50 to 4.00 D) and astigmatism (less than or equal to 1.25 D), were recruited. Participants were randomised to be fitted with orthokeratology contact lenses with a conventional compression factor (0.75 D, n = 29) or an increased compression factor (1.75 D, n = 33). Relatively fast progressors were defined as participants who had axial elongation of 0.34 mm or above per 2 years. A binomial logistic regression analysis and a classification and regression tree model were used in the data analysis. The corneal biomechanics were measured with a bidirectional applanation device. The axial length was measured by a masked examiner. RESULTS As there were no significant between-group differences in the baseline data (all p > 0.05), data were combined for analysis. The mean ± SD axial elongation for relatively slow (n = 27) and fast (n = 35) progressors were 0.18 ± 0.14 mm and 0.64 ± 0.23 mm per 2 years, respectively. The area under the curve (p2area1) was significantly higher in relatively fast progressors (p = 0.018). The binomial logistic regression and classification and regression tree model analysis showed that baseline age and p2area1 could differentiate between slow and fast progressors over 2 years. CONCLUSIONS Corneal biomechanics could be a potential predictor of axial elongation in orthokeratology contact lens-wearing children.
Collapse
Affiliation(s)
- Kin Wan
- School of Optometry, The Hong Kong Polytechnic University, HKSAR, Hong Kong, China
| | | | - Pauline Cho
- School of Optometry, The Hong Kong Polytechnic University, HKSAR, Hong Kong, China
| |
Collapse
|
3
|
Chen L, Huang Y, Zhang X, Shi Y, Gao Z, Sun B, Shen Y, Sun L, Cao Y, Zhang Q, Guo J, Li F, Chen W, Li X, Zhou X. Corneal Biomechanical Properties Demonstrate Anisotropy and Correlate With Axial Length in Myopic Eyes. Invest Ophthalmol Vis Sci 2023; 64:27. [PMID: 37477932 PMCID: PMC10365135 DOI: 10.1167/iovs.64.10.27] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 06/12/2023] [Indexed: 07/22/2023] Open
Abstract
Purpose The purpose of this study was to investigate the ex vivo and in vivo biomechanical characteristic of cornea in myopic eyes. Methods Fifty-one corneal stromal lenticules were obtained from myopic eyes during the SMILE procedure and were tested by a biaxial tensile system within 24 hours postoperatively. The material properties of the lenticules were described using stress-strain curves and were compared among axial length (AL) <26 mm and AL ≥ 26 mm group. Pre-operative stress-strain index (SSI) parameters were used to evaluate the biomechanical properties of the cornea in vivo. Results Compared with AL < 26 mm, the tangent modulus significantly decreased in horizontal and vertical directions when AL ≥ 26 mm (P < 0.05); SSI also significantly decreased when AL ≥ 26 mm (P < 0.05). Anisotropic parameter is positively correlated with AL (r = 0.307, P < 0.05). Compared with AL < 26 mm, anisotropic parameter significantly increased when AL ≥ 26 mm (P < 0.05). SSI was negatively correlated with AL (r = -0.380, P < 0.05) in the AL < 26 mm group but not in the AL ≥ 26 mm group (P > 0.05). Compared with 26 mm ≤ AL < 27 mm group, the tangent modulus significantly decreased in the horizontal direction (P < 0.05) but not in the vertical direction when 27 mm ≤ AL < 28 mm (P > 0.05). Conclusions The biomechanical properties of cornea decreased with the increase of AL. Tangent modulus significantly decreased in the horizontal direction compared with vertical direction. AL should be taken into account during calculation of corneal biomechanical parameters in order to improve validity.
Collapse
Affiliation(s)
- Lingfeng Chen
- College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan, Shanxi, China
| | - Yangyi Huang
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University); Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
- Shanghai Engineering Research Center of Laser and Autostereoscopic 3D for Vision Care (20DZ2255000), Shanghai, China
| | - Xiaoyu Zhang
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University); Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
- Shanghai Engineering Research Center of Laser and Autostereoscopic 3D for Vision Care (20DZ2255000), Shanghai, China
| | - Yike Shi
- College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan, Shanxi, China
| | - Zhipeng Gao
- College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan, Shanxi, China
| | - Bingqing Sun
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University); Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
- Shanghai Engineering Research Center of Laser and Autostereoscopic 3D for Vision Care (20DZ2255000), Shanghai, China
| | - Yang Shen
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University); Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
- Shanghai Engineering Research Center of Laser and Autostereoscopic 3D for Vision Care (20DZ2255000), Shanghai, China
| | - Ling Sun
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University); Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
- Shanghai Engineering Research Center of Laser and Autostereoscopic 3D for Vision Care (20DZ2255000), Shanghai, China
| | - Yifan Cao
- College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan, Shanxi, China
| | - Qianqian Zhang
- College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan, Shanxi, China
- Shanxi Bethune Hospital, Shanxi Academy of Medical Sciences, Tongji Shanxi Hospital, Third Hospital of Shanxi Medical University, Taiyuan, China
- School of Automation and Software Engineering, Shanxi University, Taiyuan, Shanxi, China
| | - Jiqiang Guo
- Shanxi Bethune Hospital, Shanxi Academy of Medical Sciences, Tongji Shanxi Hospital, Third Hospital of Shanxi Medical University, Taiyuan, China
| | - Fen Li
- College of Mechanical and Vehicle Engineering, Taiyuan University of Technology, Taiyuan, China
- Institute of Applied Mechanics, Taiyuan University of Technology, Taiyuan, China
| | - Weiyi Chen
- College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan, Shanxi, China
| | - Xiaona Li
- College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan, Shanxi, China
| | - Xingtao Zhou
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University); Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
- Shanghai Engineering Research Center of Laser and Autostereoscopic 3D for Vision Care (20DZ2255000), Shanghai, China
| |
Collapse
|
4
|
Li X, Wei A, Yang Y, Hong J, Xu J. Effect of eye rubbing on corneal biomechanical properties in myopia and emmetropia. Front Bioeng Biotechnol 2023; 11:1168503. [PMID: 37346798 PMCID: PMC10279860 DOI: 10.3389/fbioe.2023.1168503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 05/23/2023] [Indexed: 06/23/2023] Open
Abstract
Purpose: To investigate short-term changes in corneal biomechanical properties caused by eye rubbing in myopia and emmetropia and compare the different responses between the two groups. Methods: This was a prospective observational study of 57 eyes of 57 healthy subjects aged 45 years and younger. The participants were divided into myopia and emmetropia groups. All the subjects underwent eye rubbing by the same investigator using the same technique. Biomechanical parameters were recorded using the Corvis ST device before and after 1 min of eye rubbing. One week later, all the participants underwent the test again. Statistical methods were employed to compare the differences between the data from before and after the 1 min of eye rubbing and demonstrate the different responses of the two groups. Results: After 1 min of eye rubbing, smaller SP-A1 (p < 0.001), higher deformation and deflection amplitudes (p < 0.001, p = 0.012), higher peak distances (p < 0.001), earlier A1 times (p < 0.001), faster velocities (p < 0.001), and lower maximum inverse radii (p = 0.004) were observed. According to the automatic linear modeling analysis, the refractive states (B = -5.236, p = 0.010) and biomechanically corrected intraocular pressure (bIOP) (B = 0.196, p = 0.016) had influenced a decrease in the stiffness parameter at the first applanation (SP-A1). The central corneal thickness (CCT) had decreased only in the myopia group (p = 0.039). The change of SP-A1 in amplitude was larger in the myopia group than in the emmetropia group (p < 0.001). All the parameters returned to the baseline level 1 week later. Conclusion: Eye rubbing appears to alter corneal biomechanical properties temporarily and make the cornea softer, especially for myopic young patients.
Collapse
Affiliation(s)
- Xia Li
- Department of Ophthalmology, Shanghai Aier Eye Hospital, Shanghai, China
| | - Anji Wei
- Department of Ophthalmology, Eye, Ear, Nose, and Throat Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Yujing Yang
- Department of Ophthalmology, Eye, Ear, Nose, and Throat Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Jiaxu Hong
- Department of Ophthalmology, The Affiliated Hospital of Guizhou Medical University, Guiyang, China
| | - Jianjiang Xu
- Department of Ophthalmology, Eye, Ear, Nose, and Throat Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| |
Collapse
|
5
|
Shokrollahzadeh F, Hashemi H, Yekta A, Ostadimoghaddam H, Khabazkhoob M. Corneal Biomechanical Parameters after 60-Year-Old. J Curr Ophthalmol 2022; 34:284-289. [PMID: 36644461 PMCID: PMC9832466 DOI: 10.4103/joco.joco_201_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 01/08/2022] [Accepted: 01/12/2022] [Indexed: 12/09/2022] Open
Abstract
Purpose To determine the distribution of corneal biomechanical parameters in an elderly population. Methods This cross-sectional study was conducted in subjects above 60 years living in Tehran. The participants were selected using multi-stage cluster sampling. Corneal biomechanical parameters were measured in a randomly selected subsample of this population using the Reichert Ocular Response Analyzer (Reichert Ophthalmic Instruments, Inc., Buffalo, NY, USA). Results Of 470 subjects, the data of 420 participants aged over 60 years were analyzed (mean age: 69.3 ± 6.5 years and range: 61-88 years), 363 (86.4%) of whom were male. The mean and standard deviation of corneal hysteresis (CH) and corneal resistance factor (CRF) were 8.37 ± 1.55 mmHg (95% confidence interval [CI]: 8.02-8.72) and 9.06 ± 1.70 mmHg (95% CI: 8.69-9.44), respectively. The mean CH was 8.27 ± 1.54 mmHg in men and 9.25 ± 1.28 mmHg in women, and the mean CRF was 9.00 ± 1.71 mmHg in men and 9.63 ± 1.37 mmHg in women. According to the results of multiple linear logistic regression analysis, CH had a significant association with younger age (β = -0.05, P = 0.032), female sex (β = 1.83, P < 0.001), reduced maximum keratometry (β = -0.22, P = 0.06), and increased anterior chamber volume (β = 0.01, P = 0.007). CRF had a significant correlation with a younger age (β = -0.06, P = 0.02), female sex (β = 1.01, P = 0.05), central corneal thickness (β = 0.02, P < 0.001), and reduced maximum keratometry (β = -0.39, P = 0.010). Conclusion The mean CH and CRF values were low in this sample of the Iranian population aged over 60 years indicating the weaker elasticity of the corneal connective tissue.
Collapse
Affiliation(s)
- Fereshteh Shokrollahzadeh
- Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Hassan Hashemi
- Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital, Tehran, Iran
| | - Abbasali Yekta
- Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran,Address for correspondence: Abbasali Yekta, Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran. E-mail:
| | - Hadi Ostadimoghaddam
- Refractive Errors Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mehdi Khabazkhoob
- Department of Basic Sciences, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| |
Collapse
|
6
|
Moussa IR, Kassem RR, Edris NA, Khalil DH. Normal intraocular pressure in Egyptian children and meta-analysis. Eye (Lond) 2022; 36:1266-1273. [PMID: 34145417 PMCID: PMC9151725 DOI: 10.1038/s41433-021-01633-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 05/22/2021] [Accepted: 06/10/2021] [Indexed: 11/09/2022] Open
Abstract
OBJECTIVE To determine the normal intraocular pressure in a sample of Egyptian children 0-12 years of age, and compare it to that recorded in previous studies. METHODS This is a prospective cross-sectional study, including 345 eyes. All children underwent complete history taking and ophthalmic examination. Any glaucomatous patients or glaucoma suspects were excluded. Intraocular pressure was measured using Haag Streit Perkins M2 handheld applanation tonometer under topical or general anaesthesia. Three readings were recorded for each eye and the average was calculated. Central corneal thickness was measured, using handheld pachymeter (Pachmate 2), whenever possible. RESULTS The study included 345 eyes of 187 children (101 males and 86 females), aged 2 months to 12 years (mean: 5.69 ± 3.42 years). The recorded IOP was 5-20 mm Hg (mean: 11.5 ± 2.34 mm Hg). Central corneal thickness was 469-742 μm (mean: 564.8 ± 42.72 μm). The mean recorded intraocular pressure showed positive correlation with increased age (p = 0.026) and increased central corneal thickness (p = 0.037), with a difference of 1 mm Hg for every 100-μm change in central corneal thickness. The mean IOP was significantly lower than that recorded by most previous studies. A detailed comparative analysis is presented comparing our findings with other studies including grouped analysis, by country, ethnicity and tonometers used. CONCLUSIONS The mean IOP in a group of normal Egyptian children was 11.5 ± 2.34 mm Hg, with positive correlation to age and central corneal thickness. This mean intraocular pressure was lower than that previously reported in any other population.
Collapse
Affiliation(s)
| | | | - Noha Ahmed Edris
- grid.7776.10000 0004 0639 9286Ophthalmic Department, Cairo University, Cairo, Egypt
| | - Dalia Hamed Khalil
- grid.7776.10000 0004 0639 9286Ophthalmic Department, Cairo University, Cairo, Egypt
| |
Collapse
|
7
|
HARBİYELİ İİ, ERDEM E, UYSAL A, BİNOKAY H, YAĞMUR M. Korneanın biyomekanik özelliklerinin farklı glokom tiplerinde Corvis Scheimpflug teknolojisi ile değerlendirilmesi. CUKUROVA MEDICAL JOURNAL 2022. [DOI: 10.17826/cumj.1037164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
8
|
Rojananuangnit K. Corneal Hysteresis in Thais and Variation of Corneal Hysteresis in Glaucoma. CLINICAL OPTOMETRY 2021; 13:287-299. [PMID: 34629920 PMCID: PMC8493478 DOI: 10.2147/opto.s324187] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 09/16/2021] [Indexed: 06/13/2023]
Abstract
PURPOSE To collect the normal value data of corneal hysteresis in Thais and study the variation of corneal hysteresis in glaucomatous eyes. METHODS Retrospective cross-sectional study of corneal hysteresis (CH) in healthy non-glaucomatous and glaucomatous eyes. Demographic data, type and staging of glaucoma, Goldmann applanation tonometry (GAT) and ocular response analyzer parameters; CH, corneal-compensated intraocular pressure (IOPcc) and Goldmann-correlated intraocular pressure (IOPg) were collected. RESULTS Data from one eye of 465 normal participants were included for the normal value data of CH. Mean CH, IOPcc and IOPg were 10.18 ± 1.48, 15.01 ± 3.04 and 14.16 ± 3.06 mmHg, respectively. Average age was 57.21 ± 14.4 years. CH at the fifth percentile was 8.0 mmHg. Women had significantly higher CH than men (10.29 ± 1.46 vs 9.90 ± 1.49 mmHg, p=0.009). Moderate negative correlation was found between age and CH, r = -0.338, p<0.001. There were 695 glaucomatous eyes from 429 patients including primary-open angle glaucoma (POAG), primary close-angle glaucoma (PACG), normal tension glaucoma (NTG) and ocular hypertension (OHT). CH in each glaucoma type and severity stage (early, moderate and severe) were as follows: POAG: 8.74 ± 1.52 mmHg (9.22 ± 1.47, 8.74 ± 1.23 and 7.92 ± 1.40 mmHg, p<0.001), PACG: 9.09 ± 1.72 mmHg (9.85 ± 1.45, 9.04 ± 1.68 and 8.45 ± 1.74 mmHg, p= 0.004), NTG: 9.55 ± 1.67 mmHg (9.47 ± 1.38, 9.75 ± 2.42 and 9.77 ± 1.34 mmHg, p 0.525) and OHT: 10.10 ± 1.40 mmHg. CONCLUSION Compared with normal value data of corneal hysteresis, CH in glaucomatous eyes was lower. The more advanced glaucoma stage was associated with lower CH. Arising from normal value data, a low percentile of CH could be applied as the deviation value from normal and this dynamic property of CH could represent a glaucoma predictor in an effort to improve glaucoma care.
Collapse
Affiliation(s)
- Kulawan Rojananuangnit
- Glaucoma Unit, Ophthalmology Department, Mettapracharak (Wat Rai Khing) Hospital, Nakhon Pathom, Thailand
| |
Collapse
|
9
|
Zhou Q, Gao TY, Fan SJ, Peng Y, Li L, Lin Z, Han W, Lin HS, Wang NL, Liang YB. Intraocular Pressure, Age, and Central Corneal Thickness in a Healthy Chinese Children Population: The Handan Offspring Myopia Study. Ophthalmic Epidemiol 2021; 29:499-506. [PMID: 34542011 DOI: 10.1080/09286586.2021.1966806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
PURPOSE To assess the distribution and factors related to intraocular pressure (IOP) in a Chinese children population in Northern China. METHODS 1,238 offspring aged 6 to 18 years, residing in six villages, were recruited for this current study, the Handan Offspring Myopia Study. Participants underwent an interviewer-administered questionnaire and a complete ocular examination, including standardized measurement of IOP with Perkins applanation tonometry. RESULTS 1,648 eyes of 828 children were included in the analysis. The mean IOP was 13.9 ± 1.6 mmHg. The mean IOP for the study population increased from 13.0 ± 1.5 mmHg for those 6 to 7 years of age to 14.2 ± 1.4 mmHg for those 15 years of age or older (P < .001). The mean central corneal thickness (CCT) was 548.7 ± 32.1 μm, and had no difference among different age groups and gender. In univariate regression analysis, age (0.12 mmHg per 1 year old), height (0.09 mmHg per 5 cm), weight (0.02 mmHg per kg), body mass index (0.07 mmHg per 1 m/kg2), systolic blood pressure (0.06 mmHg per 5 mmHg), CCT (0.06 mmHg per 5 μm), and SE (-0.11 mmHg per 1 D) were correlated with IOP. In multivariate regression analysis, higher IOP was only associated with older ages (p = .002) and thicker CCT (p = .001). CONCLUSION The mean IOP in healthy rural Chinese children aged 6-18 years is about 14 mmHg, which is lower than in adults in the same locality. The mean IOP is slightly increasing with age during childhood, which is opposite to the result among adults. Age and CCT are the major independent factors associated with IOP.
Collapse
Affiliation(s)
- Qiang Zhou
- Department Of Ophthalmology, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
| | - Tie Ying Gao
- Department of Ophthalmology, Handan Eye Hospital, Handan, Hebei Province, China
| | - Su Jie Fan
- Department of Ophthalmology, Handan Eye Hospital, Handan, Hebei Province, China
| | - Yi Peng
- Beijing Ophthalmology & Visual Science Key Lab, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Lei Li
- Department of Ophthalmology, Handan Eye Hospital, Handan, Hebei Province, China
| | - Zhong Lin
- Department ofGlaucoma, The Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Wei Han
- Department of Ophthalmology, Handan Eye Hospital, Handan, Hebei Province, China
| | - Hai Shuang Lin
- Department ofGlaucoma, The Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Ning Li Wang
- Beijing Ophthalmology & Visual Science Key Lab, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Yuan Bo Liang
- Department ofGlaucoma, The Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China.,Glaucoma Institute, Wenzhou Medical University, Wenzhou, Zhejiang, China
| |
Collapse
|
10
|
Lee R, Chang RT, Wong IYH, Lai JSM, Lee JWY, Singh K. Assessment of corneal biomechanical parameters in myopes and emmetropes using the Corvis ST. Clin Exp Optom 2021; 99:157-62. [DOI: 10.1111/cxo.12341] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 08/04/2015] [Accepted: 08/06/2015] [Indexed: 11/27/2022] Open
Affiliation(s)
- Rachel Lee
- Stanford University School of Medicine, Palo Alto, California, USA,
| | - Robert T Chang
- Stanford University School of Medicine, Palo Alto, California, USA,
| | - Ian Y H Wong
- The Department of Ophthalmology, The University of Hong Kong Faculty of Medicine, Hong Kong, China,
| | - Jimmy S M Lai
- The Department of Ophthalmology, The University of Hong Kong Faculty of Medicine, Hong Kong, China,
| | - Jacky W Y Lee
- The Department of Ophthalmology, The University of Hong Kong Faculty of Medicine, Hong Kong, China,
| | - Kuldev Singh
- Stanford University School of Medicine, Palo Alto, California, USA,
| |
Collapse
|
11
|
Radhakrishnan H, Miranda MA, O'donnell C. Corneal biomechanical properties and their correlates with refractive error. Clin Exp Optom 2021; 95:12-8. [DOI: 10.1111/j.1444-0938.2011.00696.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Affiliation(s)
- Hema Radhakrishnan
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom, E‐mail:
| | - Marco A Miranda
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom, E‐mail:
| | - Clare O'donnell
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom, E‐mail:
| |
Collapse
|
12
|
Sedaghat MR, Momeni-Moghaddam H, Azimi A, Fakhimi Z, Ziaei M, Danesh Z, Roberts CJ, Monfared N, Jamali A. Corneal Biomechanical Properties in Varying Severities of Myopia. Front Bioeng Biotechnol 2021; 8:595330. [PMID: 33553113 PMCID: PMC7859342 DOI: 10.3389/fbioe.2020.595330] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Accepted: 12/21/2020] [Indexed: 11/20/2022] Open
Abstract
Purpose: To investigate corneal biomechanical response parameters in varying degrees of myopia and their correlation with corneal geometrical parameters and axial length. Methods: In this prospective cross-sectional study, 172 eyes of 172 subjects, the severity degree of myopia was categorized into mild, moderate, severe, and extreme myopia. Cycloplegic refraction, corneal tomography using Pentacam HR, corneal biomechanical assessment using Corvis ST and Ocular Response Analyser (ORA), and ocular biometry using IOLMaster 700 were performed for all subjects. A general linear model was used to compare biomechanical parameters in various degrees of myopia, while central corneal thickness (CCT) and biomechanically corrected intraocular pressure (bIOP) were considered as covariates. Multiple linear regression was used to investigate the relationship between corneal biomechanical parameters with spherical equivalent (SE), axial length (AXL), bIOP, mean keratometry (Mean KR), and CCT. Results: Corneal biomechanical parameters assessed by Corvis ST that showed significant differences among the groups were second applanation length (AL2, p = 0.035), highest concavity radius (HCR, p < 0.001), deformation amplitude (DA, p < 0.001), peak distance (PD, p = 0.022), integrated inverse radius (IR, p < 0.001) and DA ratio (DAR, p = 0.004), while there were no significant differences in the means of pressure-derived parameters of ORA between groups. Multiple regression analysis showed all parameters of Corvis ST have significant relationships with level of myopia (SE, AXL, Mean KR), except AL1 and AL2. Significant biomechanical parameters showed progressive reduction in corneal stiffness with increasing myopia (either with greater negative SE or greater AXL), independent of IOP and CCT. Also, corneal hysteresis (CH) or ability to dissipate energy from the ORA decreased with increasing level of myopia. Conclusions: Dynamic corneal response assessed by Corvis ST shows evidence of biomechanical changes consistent with decreasing stiffness with increasing levels of myopia in multiple parameters. The strongest correlations were with highest concavity parameters where the sclera influence is maximal.
Collapse
Affiliation(s)
| | | | - Abbas Azimi
- Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran.,Refractive Errors Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Zohreh Fakhimi
- Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mohammed Ziaei
- Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Zeynad Danesh
- Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Cynthia J Roberts
- Ophthalmology & Visual Science, Biomedical Engineering, The Ohio State University, Columbus, OH, United States
| | - Naeemeh Monfared
- Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Alireza Jamali
- Department of Optometry, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran
| |
Collapse
|
13
|
Jung Y, Park HYL, Oh S, Park CK. Corneal biomechanical responses detected using corvis st in primary open angle glaucoma and normal tension glaucoma. Medicine (Baltimore) 2020; 99:e19126. [PMID: 32049829 PMCID: PMC7035014 DOI: 10.1097/md.0000000000019126] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Structural differences have been reported between primary open angle glaucoma (POAG) and normal tension glaucoma (NTG), and biomechanical differences between POAG and NTG may account for why NTG patients are more vulnerable to lower intraocular pressure (IOP). This study compared the biomechanical properties of POAG and NTG patients using the Corvis scheimpflug technology (ST) non-contact Scheimpflug-based tonometer, and determined the factors associated with these properties.In this retrospective cross-sectional study, 46 eyes with POAG, 54 eyes with NTG, and 61 control eyes were included. A non-contact Scheimpflug-based tonometer was used to examine and compare the corneal biomechanical responses in the POAG, NTG, and normal groups. We used univariate and multivariate regression analyses to determine the factors associated with the deformation amplitude in each group.Baseline characteristics, including age, IOP, spherical equivalent, keratometry, axial length, and central corneal thickness, were similar among the 3 groups. Severity of glaucoma, as measured by mean deviation, was similar between POAG and NTG groups. Applanation 1 velocity and deformation amplitude were significantly smaller in POAG (0.13 ± 0.02 and 1.06 ± 0.14, respectively) than NTG (0.14 ± 0.01 and 1.13 ± 0.11, respectively) and normal groups (0.14 ± 0.02 and 1.13 ± 0.10, respectively). Radius of curvature was significantly larger in the POAG group compared to the normal group. In normal controls, IOP and keratometry were significant factors related to deformation amplitude. In POAG eyes, IOP was a statistically significant predictor of deformation amplitude. In NTG eyes, however, IOP , keratometry, and axial length were statistically significant predictors of deformation amplitude.POAG eyes showed less deformable corneas compared to NTG and normal controls. IOP was significantly correlated with deformation amplitude in all groups. However, axial length was positively correlated with deformation amplitude only in NTG eyes. Characterization of the differences in biomechanical properties between POAG and NTG may contribute to a better understanding of the underlying pathophysiologies associated with these diseases.
Collapse
Affiliation(s)
- Younhea Jung
- Department of Ophthalmology, Yeouido St. Mary's Hospital, College of Medicine
| | - Hae-Young L. Park
- Department of Ophthalmology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Sieun Oh
- Department of Ophthalmology, Yeouido St. Mary's Hospital, College of Medicine
| | - Chan Kee Park
- Department of Ophthalmology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| |
Collapse
|
14
|
Wu W, Dou R, Wang Y. Comparison of Corneal Biomechanics Between Low and High Myopic Eyes-A Meta-analysis. Am J Ophthalmol 2019; 207:419-425. [PMID: 31374186 DOI: 10.1016/j.ajo.2019.07.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 05/19/2019] [Accepted: 07/13/2019] [Indexed: 11/24/2022]
Abstract
PURPOSE To compare the corneal biomechanical difference between the low myopic eyes and high myopic eyes. DESIGN Systematic review and meta-analysis. METHODS Data sources, including PubMed, Medline, EMBASE, Web of Science, and Chinese databases including Wanfang and China National Knowledge Infrastructure, were searched to find the relevant studies. Primary outcomes were corneal hysteresis (CH), corneal resistance factor (CRF), corneal-compensated intraocular pressure (IOPcc), Goldmann-correlated intraocular pressure (IOPg), and central corneal thickness (CCT) in high myopic eyes and low myopic eyes. RESULTS Eleven studies were enrolled in this study. CH and CRF were significantly higher in the low myopic eyes. The mean difference of CH was 0.73 mm Hg, 95% confidence interval (CI) [0.53 to 0.93], P < .001. The mean difference of CRF was 0.20 mm Hg, 95% CI [0.04 to 0.37], P = .02. The IOPcc and IOPg were significantly lower in the low myopic eyes. The mean difference of IOPcc was -2.53 mm Hg, 95% CI [-3.24, -1.83], P < .01. The mean difference of IOPg was -1.42 mm Hg, 95% CI [-2.26, -0.58], P = .0009. There was no significant difference between the 2 groups on CCT; the mean difference was -2.85 μm, 95% CI [-9.64.3.93], P = .41. CONCLUSION Corneal biomechanics are different in the high myopic eyes. Low CH and CRF and high IOPcc and IOPg are suggested to be associated factors for high myopia. Future studies are needed to investigate the underlying corneal structure difference that causes the low CH and CRF value in the high myopic eyes.
Collapse
|
15
|
Wolffsohn JS, Kollbaum PS, Berntsen DA, Atchison DA, Benavente A, Bradley A, Buckhurst H, Collins M, Fujikado T, Hiraoka T, Hirota M, Jones D, Logan NS, Lundström L, Torii H, Read SA, Naidoo K. IMI - Clinical Myopia Control Trials and Instrumentation Report. Invest Ophthalmol Vis Sci 2019; 60:M132-M160. [PMID: 30817830 DOI: 10.1167/iovs.18-25955] [Citation(s) in RCA: 87] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The evidence-basis based on existing myopia control trials along with the supporting academic literature were reviewed; this informed recommendations on the outcomes suggested from clinical trials aimed at slowing myopia progression to show the effectiveness of treatments and the impact on patients. These outcomes were classified as primary (refractive error and/or axial length), secondary (patient reported outcomes and treatment compliance), and exploratory (peripheral refraction, accommodative changes, ocular alignment, pupil size, outdoor activity/lighting levels, anterior and posterior segment imaging, and tissue biomechanics). The currently available instrumentation, which the literature has shown to best achieve the primary and secondary outcomes, was reviewed and critiqued. Issues relating to study design and patient selection were also identified. These findings and consensus from the International Myopia Institute members led to final recommendations to inform future instrumentation development and to guide clinical trial protocols.
Collapse
Affiliation(s)
- James S Wolffsohn
- Ophthalmic Research Group, Aston University, Birmingham, United Kingdom
| | - Pete S Kollbaum
- Indiana University, School of Optometry, Bloomington, Indiana, United States
| | - David A Berntsen
- The Ocular Surface Institute, College of Optometry, University of Houston, Houston, Texas, United States
| | - David A Atchison
- School of Optometry and Vision Science, Institute of Health and Biomedical Innovation, Queensland University of Technology, Australia
| | | | - Arthur Bradley
- Indiana University, School of Optometry, Bloomington, Indiana, United States
| | - Hetal Buckhurst
- School of Health Professions, Peninsula Allied Health Centre, Plymouth University, Plymouth, United Kingdom
| | - Michael Collins
- School of Optometry and Vision Science, Institute of Health and Biomedical Innovation, Queensland University of Technology, Australia
| | - Takashi Fujikado
- Department of Applied Visual Science, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Takahiro Hiraoka
- Department of Ophthalmology, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan
| | - Masakazu Hirota
- Department of Applied Visual Science, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Debbie Jones
- School of Optometry and Vision Science, University of Waterloo, Waterloo, Ontario, Canada
| | - Nicola S Logan
- Ophthalmic Research Group, Aston University, Birmingham, United Kingdom
| | | | - Hidemasa Torii
- Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan
| | - Scott A Read
- School of Optometry and Vision Science, Institute of Health and Biomedical Innovation, Queensland University of Technology, Australia
| | - Kovin Naidoo
- African Vision Research Institute, University of KwaZulu-Natal, Durban, South Africa
| |
Collapse
|
16
|
Momeni-Moghaddam H, Hashemi H, Zarei-Ghanavati S, Ostadimoghaddam H, Yekta A, Aghamirsalim M, Khabazkhoob M. Four-year changes in corneal biomechanical properties in children. Clin Exp Optom 2019; 102:489-495. [PMID: 30887574 DOI: 10.1111/cxo.12890] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 12/26/2018] [Accepted: 02/05/2019] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND To determine four-year changes of corneal biomechanical parameters in Iranian children aged seven to eleven years and their correlation with optical components. METHODS In this four-year prospective cohort study, 468 children aged seven to eleven years who were initially evaluated in 2012 were re-evaluated in 2016-2017. Multi-stage stratified cluster sampling was applied. Cycloplegic refraction, biometry using LENSTAR/BioGraph, and corneal biomechanical assessment using Ocular Response Analyzer (ORA) were undertaken for each participant. The corneal biomechanical parameters assessed were corneal hysteresis (CH), corneal resistance factor (CRF), areas under the peaks 1 and 2 (p1 and p2 areas) and irregularity indices (A and B indices). RESULTS All biomechanical parameters except A index decreased in phase 2. The mean changes of CH and CRF were 0.68 ± 0.16 mmHg (for both parameters) during four years. The mean difference in CH and CRF was 0.23 ± 0.23 and 0.24 ± 0.23 mmHg in females and 1.03 ± 0.23 and 0.96 ± 0.23 mmHg in males, respectively. Different age groups showed varying amounts of decrease in all parameters except for A index. The age group 'ten years' experienced the smallest decrease in CH (0.02 ± 0.48 mmHg) and CRF (0.20 ± 0.47 mmHg) and the age group 'eleven years' showed the greatest decrease in CH (1.41 ± 0.35 mmHg) and CRF (0.99 ± 0.34 mmHg). According to linear regression analysis, CH and CRF had a significant direct relationship with corneal power and an inverse relationship with axial length (p < 0.001). CONCLUSION Age and sex are influencing factors on the ORA parameters. Older age is associated with reduced biomechanical parameters and reductions are more significant in males than females. Axial elongation and corneal flattening decrease CH and CRF.
Collapse
Affiliation(s)
- Hamed Momeni-Moghaddam
- Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Hassan Hashemi
- Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital, Tehran, Iran
| | | | - Hadi Ostadimoghaddam
- Refractive Errors Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Abbasali Yekta
- Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
| | | | - Mehdi Khabazkhoob
- Department of Medical Surgical Nursing, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| |
Collapse
|
17
|
Shoeibi N, Ansari-Astaneh MR, Sedaghat MR, Shokoohi Rad S. Effect of Intravitreal Bevacizumab Injection on Corneal in vivo Biomechanics: A Pilot Study. J Ophthalmic Vis Res 2019; 14:151-156. [PMID: 31114651 PMCID: PMC6504725 DOI: 10.4103/jovr.jovr_257_17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Purpose To evaluate the effect of intravitreal bevacizumab (IVB) injection on corneal biomechanical parameters as measured by the ocular response analyzer (ORA) and Corneal Visualization Scheimpflug Technology (CorVis). Methods In this prospective pilot study, ORA and CorVis parameters were recorded before and after a three-month course of IVB injection therapy in 16 patients in the injected and the contralateral non-injected control eyes. The changes in the recorded parameters in each group and the differences between the two groups were evaluated and compared. Results None of the changes in ORA parameters were statistically significant in the injected and non-injected groups before and three months after injection, except for corneal resistance factor (CRF) in injected eyes (paired t-test, P = 0.039). The differences in corneal hysteresis (CH) and CRF were not statistically significant between the two groups (P = 0.441 and 0.236, respectively), but significant differences were noted between corneal compensated IOP (IOPcc) and Goldmann-correlated IOP (IOPg) (P = 0.045 and 0.047, respectively). None of the changes in CorVis parameters were statistically significant in the groups before and at the end of study, except for the time of first corneal applanation (TAp1 ms) in the injected group (P = 0.040, paired t-test). Differences in TAp1, length of the second corneal applanation (LAp2 mm), velocity of the second corneal applanation (VAp2 m/s), intraocular pressure (IOP), and central corneal thickness (CCT) also showed borderline significance between the two groups. Conclusion In this pilot study IVB injection could change CRF, IOPcc, IOPg, and TAP1 as measured by ORA and CorVis.
Collapse
Affiliation(s)
- Nasser Shoeibi
- Eye Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.,Retina Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mohammad-Reza Ansari-Astaneh
- Eye Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.,Retina Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mohammad Reza Sedaghat
- Eye Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.,Cornea Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Saeed Shokoohi Rad
- Eye Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.,Cornea Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| |
Collapse
|
18
|
Wan K, Cheung SW, Wolffsohn JS, Orr JB, Cho P. Role of corneal biomechanical properties in predicting of speed of myopic progression in children wearing orthokeratology lenses or single-vision spectacles. BMJ Open Ophthalmol 2018; 3:e000204. [PMID: 30687783 PMCID: PMC6326267 DOI: 10.1136/bmjophth-2018-000204] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Objective To determine the characteristics of children who were likely to progress rapidly and gain the greatest benefit from orthokeratology (ortho-k) treatment. Methods and analysis The files of 113 children who participated in two myopia control studies and wore either ortho-k lenses (n=62) or single-vision spectacles (SVS) (n=51) were reviewed. Baseline cycloplegic subjective refraction, central corneal thickness, axial length, keratometry, intraocular pressure, corneal biomechanical properties and 24-month axial length data were retrieved and analysed. Results Multivariate analysis showed that there was significant negative correlation between axial elongation and baseline age and corneal hysteresis (p<0.05) in the SVS group. In the ortho-k group, only baseline age was significantly and negatively associated with axial elongation (p<0.01). Conclusion Corneal biomechanical properties and baseline age can predict the rate of axial elongation in myopic children. It may be beneficial for younger myopic children with low corneal hysteresis to commence ortho-k treatment as early as possible.
Collapse
Affiliation(s)
- Kin Wan
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong, Hong Kong
| | - Sin Wan Cheung
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong, Hong Kong
| | - James S Wolffsohn
- School of Life and Health Sciences, Aston University, Birmingham, UK
| | - Janis B Orr
- School of Life and Health Sciences, Aston University, Birmingham, UK
| | - Pauline Cho
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong, Hong Kong
| |
Collapse
|
19
|
Bueno-Gimeno I, Martínez-Albert N, Gené-Sampedro A, España-Gregori E. Anterior Segment Biometry and Their Correlation with Corneal Biomechanics in Caucasian Children. Curr Eye Res 2018; 44:118-124. [PMID: 30346843 DOI: 10.1080/02713683.2018.1539181] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
PURPOSE To assess the relationship between the corneal biomechanical parameters and the anterior segment parameters in Caucasian children. METHODS This study included 293 eyes from 293 healthy children aged between 6 and 17 years. Corneal hysteresis (CH) and corneal resistance factor (CRF) were evaluated with the Ocular Response Analyzer, axial length (AL) with IOLMaster and the anterior segment with Pentacam. Anterior segment parameters obtained were the following: central corneal thickness (CCT), corneal volume (CV), anterior chamber depth (ACD), anterior chamber volume (ACV) and mean anterior and posterior keratometry. Two multiple linear regression models were constructed to assess the association between CH and CRF with anterior segment parameters. A value of p < 0.05 was taken as the criterion for statistical significance in all analyses. RESULTS The mean CH and CRF were 12.12 ± 1.71 and 12.30 ± 1.89 mmHg, respectively. Multiple linear regression revealed that CH and CRF were associated negatively with AL in both models, and positively with CCT and CV in the first and second model, respectively. Meanwhile ACD, ACV or mean keratometry did not correlated with CH and CRF. Moreover, when CCT was in the model, it explained more variability for both CH (22.1%) and CRF (30.9%) than when CV was included (16.2% for CH and 16.5% for CRF). CONCLUSIONS CH and CRF were correlated positively with CCT and CV, and negatively with AL in healthy Caucasian children. Moreover, corneal parameters were the most contributory variables to CH and CRF changes.
Collapse
Affiliation(s)
| | - Noelia Martínez-Albert
- a Department of Optics and Optometry and Vision Sciences , University of Valencia , Spain
| | - Andrés Gené-Sampedro
- a Department of Optics and Optometry and Vision Sciences , University of Valencia , Spain
| | - Enrique España-Gregori
- b Department of Surgery , University of Valencia , Spain.,c University Hospital La Fe , Spain
| |
Collapse
|
20
|
Corneal hysteresis in post-radial keratotomy primary open-angle glaucoma. Graefes Arch Clin Exp Ophthalmol 2018; 256:1971-1976. [DOI: 10.1007/s00417-018-4073-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Revised: 06/24/2018] [Accepted: 07/16/2018] [Indexed: 11/27/2022] Open
|
21
|
Biomechanical Properties of Axially Myopic Cornea. Eur J Ophthalmol 2018; 22 Suppl 7:S24-8. [DOI: 10.5301/ejo.5000010] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/19/2011] [Indexed: 11/20/2022]
|
22
|
Hashemi H, Saatchi M, Khabazkhoob M, Emamian MH, Yekta A, Fotouhi A. Distribution of corneal thickness and its determinants in 6-12-year-old children in an Iranian general population. J Curr Ophthalmol 2017; 31:150-156. [PMID: 31317092 PMCID: PMC6611839 DOI: 10.1016/j.joco.2017.12.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 11/25/2017] [Accepted: 12/05/2017] [Indexed: 10/29/2022] Open
Abstract
Purpose To determine the central corneal thickness (CCT), apex, and paracentral thicknesses and their determinants in children aged 6-12 years. Methods The present study was part of the phase 1 of Shahroud School Children Eye Cohort Study in 2015. Cluster sampling was done in urban areas while all children were invited to participate in the study in rural areas. The Pentacam HR was used for measurements. CCT was measured within the central 3 mm zone of the cornea, and corneal thickness 3 mm further from the center was considered paracentral thickness. Results Of 6624 students who were selected, 5620 (84.8%) participated in the study. Among 4956 students, studied in this report, 52.2% were boys, and the mean age of the study participants was 9.75 ± 1.71 years (6-12). The mean CCT and apical thickness was 556.29 ± 34.04 and 557.43 ± 34.03 μm, respectively. The mean paracentral thickness was 657.62 ± 39.11 μm in the superior, 632.65 ± 37.63 μm in the inferior, 648.64 ± 38.75 μm in the nasal, and 617.36 ± 37.19 μm in the temporal region. A multiple regression model showed that CCT decreased by 4.70 μm with every 1 diopter increase in the mean keratometry and increased by 20.06 μm with every 1 mm increase in the anterior chamber depth (ACD) (Both P-Value < 0.001). Age, sex, ethnicity and residence place were also found to be associated with CCT. Conclusions This study is the first to describe the distribution of corneal thickness in Iranian children with a large sample size. This study showed that corneal thickness was significantly correlated with younger age, female gender, urban residence, and a number of biometric variables.
Collapse
Affiliation(s)
- Hassan Hashemi
- Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital, Tehran, Iran
| | - Mohammad Saatchi
- Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital, Tehran, Iran
| | - Mehdi Khabazkhoob
- Department of Medical Surgical Nursing, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran
| | - Mohammad Hassan Emamian
- Ophthalmic Epidemiology Research Center, Shahroud University of Medical Sciences, Shahroud, Iran
- Corresponding author.
| | - Abbasali Yekta
- Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Akbar Fotouhi
- Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| |
Collapse
|
23
|
Miki A, Maeda N, Asai T, Ikuno Y, Nishida K. Measurement repeatability of the dynamic Scheimpflug analyzer. Jpn J Ophthalmol 2017; 61:433-440. [PMID: 28983780 DOI: 10.1007/s10384-017-0534-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2016] [Accepted: 07/28/2017] [Indexed: 10/18/2022]
Abstract
PURPOSE To evaluate the repeatability of corneal deformation parameters measured using a dynamic Scheimpflug analyzer and the impact of baseline clinical factors on the repeatability of each parameter. STUDY DESIGN Retrospective, cross-sectional study. METHODS Forty-eight eyes (48 healthy subjects; mean age, 49.0 ± 19.5 years) underwent repeated examinations with the Scheimpflug analyzer to evaluate the test-retest variability. The intraclass correlation coefficient (ICC) and repeatability coefficient as indicators of variability were computed for 35 parameters measured with the Scheimpflug analyzer. The associations between the magnitude of the test-retest variability and baseline factors, such as age, axial length (AL), intraocular pressure (IOP), and central corneal thickness (CCT), were analyzed. RESULTS The test-retest repeatability was excellent for 22 (62.9%) of 35 parameters (ICC ≥ 0.75), good for seven (20%), (ICC ≥ 0.6), fair for four (11.4%), (ICC ≥ 0.4), and poor for two (5.7%) parameters (ICC < 0.4). Age was associated positively with the magnitude of variability in 13 (37.1%) parameters; measurement variability was affected significantly by AL (5 parameters, 14.3%) and CCT (7 parameters, 20%) but, except for one parameter not by IOP. CONCLUSION Most parameters of the dynamic Scheimpflug analyzer showed favorable measurement reliability in healthy subjects. However, six parameters showed poor-to-fair repeatability. Age, AL, and CCT significantly affected the repeatability of several parameters. These results should be considered when clinicians use this device in clinical practice.
Collapse
Affiliation(s)
- Atsuya Miki
- Department of Ophthalmology, Osaka University Graduate School of Medicine, 2-2 Yamada-Oka, Suita, Osaka, 565-0871, Japan.
| | - Naoyuki Maeda
- Department of Ophthalmology, Osaka University Graduate School of Medicine, 2-2 Yamada-Oka, Suita, Osaka, 565-0871, Japan
| | - Tomoko Asai
- Department of Ophthalmology, Osaka University Graduate School of Medicine, 2-2 Yamada-Oka, Suita, Osaka, 565-0871, Japan
| | - Yasushi Ikuno
- Department of Ophthalmology, Osaka University Graduate School of Medicine, 2-2 Yamada-Oka, Suita, Osaka, 565-0871, Japan
| | - Kohji Nishida
- Department of Ophthalmology, Osaka University Graduate School of Medicine, 2-2 Yamada-Oka, Suita, Osaka, 565-0871, Japan
| |
Collapse
|
24
|
İnceoğlu N, Emre S, Ulusoy MO. Investigation of corneal biomechanics at moderate to high refractive errors. Int Ophthalmol 2017; 38:1061-1067. [DOI: 10.1007/s10792-017-0560-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2017] [Accepted: 05/10/2017] [Indexed: 11/30/2022]
|
25
|
Corneal biomechanical metrics of healthy Chinese adults using Corvis ST. Cont Lens Anterior Eye 2017; 40:97-103. [DOI: 10.1016/j.clae.2016.12.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 11/30/2016] [Accepted: 12/06/2016] [Indexed: 11/19/2022]
|
26
|
Nemeth G, Szalai E, Hassan Z, Lipecz A, Flasko Z, Modis L. Corneal biomechanical data and biometric parameters measured with Scheimpflug-based devices on normal corneas. Int J Ophthalmol 2017; 10:217-222. [PMID: 28251079 DOI: 10.18240/ijo.2017.02.06] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 09/27/2016] [Indexed: 12/19/2022] Open
Abstract
AIM To analyze the correlations between ocular biomechanical and biometric data of the eye, measured by Scheimpflug-based devices on healthy subjects. METHODS Three consecutive measurements were carried out using the corneal visualization Scheimpflug technology (CorVis ST) device on healthy eyes and the 10 device-specific parameters were recorded. Pentacam HR-derived parameters (corneal curvature radii on the anterior and posterior surfaces; apical pachymetry; corneal volume; corneal aberration data; depth, volume and angle of the anterior chamber) and axial length (AL) from IOLMaster were correlated with the 10 specific CorVis ST parameters. RESULTS Measurements were conducted in 43 eyes of 43 volunteers (age 61.24±15.72y). The 10 specific CorVis ST data showed significant relationships with corneal curvature radii both on the anterior and posterior surface, pachymetric data, root mean square (RMS) data of lower-order aberrations, and posterior RMS of higher-order aberrations and spherical aberration of the posterior cornea. Anterior chamber depth showed a significant relationship, but there were no significant correlations between corneal volume, anterior chamber volume, mean chamber angle or AL and the 10 specific CorVis ST parameters. CONCLUSIONS CorVis ST-generated parameters are influenced by corneal curvature radii, some corneal RMS data, but corneal volume, anterior chamber volume, chamber angle and AL have no correlation with the biomechanical parameters. The parameters measured by CorVis ST seem to refer mostly to corneal properties of the eye.
Collapse
Affiliation(s)
- Gabor Nemeth
- Department of Ophthalmology, Borsod-Abaúj-Zemplén County Hospital and University Teaching Hospital, Miskolc 3526, Hungary
| | - Eszter Szalai
- Department of Ophthalmology, University of Debrecen, Debrecen 4032, Hungary
| | - Ziad Hassan
- Orbi-Dent Refractive Surgery and Medical Centre, Debrecen 4032, Hungary
| | - Agnes Lipecz
- Department of Ophthalmology, University of Debrecen, Debrecen 4032, Hungary
| | - Zsuzsa Flasko
- Department of Ophthalmology, University of Debrecen, Debrecen 4032, Hungary
| | - Laszlo Modis
- Department of Ophthalmology, University of Debrecen, Debrecen 4032, Hungary
| |
Collapse
|
27
|
Corneal Biomechanics Determination in Healthy Myopic Subjects. J Ophthalmol 2016; 2016:2793516. [PMID: 27525109 PMCID: PMC4972914 DOI: 10.1155/2016/2793516] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 06/22/2016] [Accepted: 06/28/2016] [Indexed: 11/25/2022] Open
Abstract
Purpose. To determine the corneal biomechanical properties by using the Ocular Response Analyzer™ and to investigate potential factors associated with the corneal biomechanics in healthy myopic subjects. Methods. 135 eyes from 135 healthy myopic subjects were included in this cross-sectional observational study. Cornea hysteresis (CH), corneal resistance factor (CRF), cornea-compensated intraocular pressure (IOPcc), and Goldmann-correlated intraocular pressure (IOPg) were determined with the Reichert Ocular Response Analyzer (ORA). Univariate and multivariate regression analyses were performed to investigate factors associated with corneal biomechanics. Results. The mean CH and CRF were 9.82 ± 1.34 mmHg and 9.64 ± 1.57 mmHg, respectively. In univariate regression analysis, CH was significantly correlated with axial length, refraction, central corneal thickness (CCT), and IOPg (r = −0.27, 0.23, 0.45, and 0.21, resp.; all with p ≤ 0.015), but not with corneal curvature or age; CRF was significantly correlated with CCT and IOPg (r = 0.52 and 0.70, resp.; all with p < 0.001), but not with axial length/refraction, corneal curvature, or age. In multivariate regression analysis, axial length, IOPcc, and CCT were found to be independently associated with CH, while CCT and IOPg were associated with CRF. Conclusions. Both CH and CRF were positively correlated with CCT. Lower CH but not CRF was associated with increasing degree of myopia. Evaluation of corneal biomechanical properties should take CCT and myopic status into consideration.
Collapse
|
28
|
Matalia J, Francis M, Tejwani S, Dudeja G, Rajappa N, Sinha Roy A. Role of Age and Myopia in Simultaneous Assessment of Corneal and Extraocular Tissue Stiffness by Air-Puff Applanation. J Refract Surg 2016; 32:486-93. [DOI: 10.3928/1081597x-20160512-02] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 03/17/2016] [Indexed: 11/20/2022]
|
29
|
Wu N, Chen Y, Yu X, Li M, Wen W, Sun X. Changes in Corneal Biomechanical Properties after Long-Term Topical Prostaglandin Therapy. PLoS One 2016; 11:e0155527. [PMID: 27187282 PMCID: PMC4871478 DOI: 10.1371/journal.pone.0155527] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Accepted: 04/29/2016] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVE To compare corneal biomechanical properties, measured by a newly developed tonometer (Corneal Visualization Scheimpflug Technology, Corvis ST), in untreated primary open angle glaucoma (POAG) patients, POAG patients with long-term topical prostaglandin analog (PGA) therapy and in normal controls. Further is to investigate the potential effects of PGA on corneal biomechanics. METHODS In this case-control study, 35 consecutive medication naïve eyes with POAG, 34 POAG eyes with at least 2 years treatment by PGA and 19 normal eyes were included. Intraocular pressure (IOP), central corneal thickness (CCT) and corneal biomechanical parameters, including deformation amplitude (DA), applanation time (AT1 and AT2), applanation length (AL1 and AL2), applanation velocity (AV1 and AV2), and peak distance and radius were measured using Corvis ST. Axial length and corneal curvature were measured with partial coherence interferometry (IOLMaster, Zeiss, Germany). General linear model analysis was performed to investigate the corneal biomechanical property changes among the normal controls, newly diagnosed POAG patients and POAG patients with long-term PGA treatment, and among the subgroups of different types of PGA treatment, including bimatoprost, latanoprost and travoprost. Furthermore, pairwise comparisons using Bonferroni correction for least squares means were employed. RESULTS AT1 (p<0.0001), AV1 (p<0.0001), AT2 (p = 0.0001), AV2 (p<0.0001) and DA (p = 0.0004) in newly diagnosed glaucoma patients were significantly different from those in normal subjects and in patients underwent at least 2 years topical PGA therapy after adjusting for age and gender. After adjusting for age, gender, IOP, CCT, axial length and corneal curvature, a significant difference was detected for DA between glaucoma patients without PGA treatment and patients with long-term PGA therapy (p = 0.0387). Furthermore, there were no statistical significant differences in all of the corneal biomechanical parameters among the 3 types of PGA therapy subgroups, namely bimatoprost, latanoprost and travoprost. CONCLUSIONS Significant changes in corneal deformation parameters were found among untreated POAG patients, POAG patients with long-term topical PGA therapy and normal controls. Long-term topical PGA treatment might have a direct effect on corneal biomechanical properties in addition to the indirect effect owing to the PGA-induced IOP reduction and CCT decrease on corneal dynamic properties.
Collapse
Affiliation(s)
- Na Wu
- Department of Ophthalmology and Visual Science, Eye and ENT Hospital of Fudan University, Shanghai, China
- Key Laboratory of Myopia, Ministry of Health (Fudan University), Shanghai, China
| | - Yuhong Chen
- Department of Ophthalmology and Visual Science, Eye and ENT Hospital of Fudan University, Shanghai, China
- Key Laboratory of Myopia, Ministry of Health (Fudan University), Shanghai, China
| | - Xiaobo Yu
- Department of Ophthalmology and Visual Science, Eye and ENT Hospital of Fudan University, Shanghai, China
- Key Laboratory of Myopia, Ministry of Health (Fudan University), Shanghai, China
| | - Mengwei Li
- Department of Ophthalmology and Visual Science, Eye and ENT Hospital of Fudan University, Shanghai, China
- Key Laboratory of Myopia, Ministry of Health (Fudan University), Shanghai, China
| | - Wen Wen
- Department of Ophthalmology and Visual Science, Eye and ENT Hospital of Fudan University, Shanghai, China
- Key Laboratory of Myopia, Ministry of Health (Fudan University), Shanghai, China
| | - Xinghuai Sun
- Department of Ophthalmology and Visual Science, Eye and ENT Hospital of Fudan University, Shanghai, China
- Key Laboratory of Myopia, Ministry of Health (Fudan University), Shanghai, China
- Shanghai Key Laboratory of Visual Impairment and Restoration (Fudan University), Shanghai, China
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Fudan University, Shanghai, China
| |
Collapse
|
30
|
Abstract
PURPOSE To compare the corneal biomechanical properties and intraocular pressure (IOP) levels in patients with and without arcus senilis (AS). METHODS Ocular response analyzer measurements were performed on the right eyes of 37 patients with AS (group 1) and 37 control eyes (group 2). Corneal hysteresis, corneal resistance factor, Goldmann-correlated IOP, and corneal compensated IOP were recorded with Ocular response analyzer. Spherical equivalent value of the refractive errors, axial length, central corneal thickness, and IOP measured with Goldmann applanation tonometer were noted for each study eyes. Statistical analyses were performed with Student t, Kruskal-Wallis, and Pearson correlation tests. RESULTS Mean age was 67.6 ± 9.8 years in group 1 and 65.3 ± 8.1 years in group 2 (P = 0.308). Mean corneal hysteresis and corneal resistance factor readings were 9.8 ± 0.9 versus 10.6 ± 0.8 (P < 0.001) and 10.05 ± 1.07 versus 10.9 ± 0.9 (P < 0.001) in groups 1 and 2, respectively. Mean corneal compensated IOP and Goldmann-correlated IOP values were found as 16.1 ± 3.3 mm Hg versus 15.8 ± 2.6 mm Hg (P = 0.719) and 15.1 ± 3.3 mm Hg versus 15.0 ± 2.6 mm Hg (P = 0.912) in groups 1 and 2, respectively. There was no statistical difference in IOP measured with Goldmann applanation tonometer, central corneal thickness, spherical equivalent value of the refractive error, axial length measurements, and mean keratometry readings between the 2 groups (P = 0.983, P = 0.289, P = 0.938, P = 0.886, P = 0.07, respectively). CONCLUSIONS The mean corneal hysteresis and corneal resistance factor values of eyes with AS were lower when compared with the controls. This study demonstrated that AS may change the corneal biomechanical properties.
Collapse
|
31
|
The Icare-Pro Rebound Tonometer Versus the Hand-held Applanation Tonometer in Congenital Glaucoma. J Glaucoma 2016; 25:149-54. [DOI: 10.1097/ijg.0000000000000177] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
32
|
Ma Y, Zhu X, He X, Lu L, Zhu J, Zou H. Corneal Thickness Profile and Associations in Chinese Children Aged 7 to 15 Years Old. PLoS One 2016; 11:e0146847. [PMID: 26751798 PMCID: PMC4709113 DOI: 10.1371/journal.pone.0146847] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Accepted: 12/22/2015] [Indexed: 12/29/2022] Open
Abstract
Corneal thickness (CT) maps of the central (2-mm diameter), para-central (2 to 5-mm diameter), peripheral (5 to 6-mm diameter), and minimum (5-mm diameter) cornea were measured in normal Chinese school children aged 7 to 15 years old using Fourier-domain optical coherence tomography. Multiple regression analyses were performed to explore the effect of associated factors [age, gender, refraction, axial length and corneal curvature radius (CCR)] on CT and the relationship between central corneal thickness (CCT) and intraocular pressure (IOP). A total of 1228 eyes from 614 children were analyzed. The average CCT was 532.96 ± 28.33 μm for right eyes and 532.70 ±28.45 μm for left eyes. With a 10 μm increase in CCT, the IOP was elevated by 0.37 mm Hg, as measured by noncontact tonometry. The CT increased gradually from the center to the periphery. The superior and superior nasal regions had the thickest CTs, while the thinnest points were primarily located in the inferior temporal cornea. The CCT was associated with CCR (p = 0.008) but not with gender (p = 0.075), age (p = 0.286), axial length (p = 0.405), or refraction (p = 0.985). In the para-central region and the peripheral cornea, increased CT was associated with younger age, male gender, and a flatter cornea.
Collapse
Affiliation(s)
- Yingyan Ma
- Shanghai Eye Hospital, Shanghai Eye Disease Prevention & Treatment Center, Shanghai, China
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiaofeng Zhu
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiangui He
- Shanghai Eye Hospital, Shanghai Eye Disease Prevention & Treatment Center, Shanghai, China
- Department of Maternal and Child Health, School of Public Health, Key Laboratory of Public Health Safety, Ministry of Education, Fudan University, Shanghai, China
| | - Lina Lu
- Shanghai Eye Hospital, Shanghai Eye Disease Prevention & Treatment Center, Shanghai, China
| | - Jianfeng Zhu
- Shanghai Eye Hospital, Shanghai Eye Disease Prevention & Treatment Center, Shanghai, China
| | - Haidong Zou
- Shanghai Eye Hospital, Shanghai Eye Disease Prevention & Treatment Center, Shanghai, China
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- * E-mail:
| |
Collapse
|
33
|
Yülek F, Gerçeker S, Akçay E, Saraç Ö, Çağıl N. Corneal biomechanics in steroid induced ocular hypertension. Cont Lens Anterior Eye 2015; 38:181-4. [DOI: 10.1016/j.clae.2015.01.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 01/26/2015] [Accepted: 01/26/2015] [Indexed: 11/28/2022]
|
34
|
Öner V, Taş M, Özkaya E, Oruç Y. Effect of pathological myopia on biomechanical properties: a study by ocular response analyzer. Int J Ophthalmol 2015; 8:365-8. [PMID: 25938057 DOI: 10.3980/j.issn.2222-3959.2015.02.27] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Accepted: 07/23/2014] [Indexed: 12/13/2022] Open
Abstract
AIM To evaluate the ocular response analyzer (ORA) measurements of patients with pathological myopia in comparison with those of emmetropic control subjects, and to investigate the correlation between these ORA measurements and spherical equivalent (SE). METHODS Measurements of 53 eyes of 53 subjects with pathological myopia (SE>-6.00 D) were compared with those of 60 eyes of 60 emmetropic controls. Corneal hysteresis (CH), corneal resistance factor (CRF), noncontact tonometer intraocular pressure (IOPg), and corneal-compensated IOP (IOPcc) were obtained for each subject. The refractive error value was determined as SE via a cycloplegic refraction test. RESULTS The mean age was 54.1±18.9y (ranging from 5 to 88) in the pathological myopic group and 56.2±19.0y (ranging from 6 to 89) in the control group. There were no significant differences between the groups concerning age and sex. CH and CRF were significantly lower in the pathological myopic group than in the control group (P<0.001, P=0.005, respectively). IOPcc and IOPg were significantly higher in the pathological myopic group than in the control group (P<0.001, P=0.009, respectively). There were significantly positive correlations between CH and SE (r=0.565, P<0.001) and between CRF and SE (r=0.364, P=0.007). There were significantly negative correlations between IOPcc and SE (r=-0.432, P=0.001) and between IOPg and SE (r=-0.401, P=0.003). CONCLUSION The present study displayed that pathological myopia affected biomechanical properties measured by ORA. The results of corneal biomechanical properties measured by ORA may need to be appreciated by taking refraction into account. Further, pathological myopia might be related with the increased IOP.
Collapse
Affiliation(s)
- Veysi Öner
- Department of Ophthalmology, Recep Tayyip Erdoğan University Medical School, Rize 53100, Turkey
| | - Mehmet Taş
- Department of Ophthalmology, Malatya State Hospital, Malatya 44000, Turkey
| | - Erdal Özkaya
- Department of Ophthalmology, Malatya State Hospital, Malatya 44000, Turkey
| | - Yavuz Oruç
- Department of Ophthalmology, Recep Tayyip Erdoğan University Education and Research Hospital, Rize 53100, Turkey
| |
Collapse
|
35
|
Abstract
PURPOSE To evaluate the possible associations between corneal biomechanical parameters, optic disc morphology, and retinal nerve fiber layer (RNFL) thickness in healthy white Spanish children. METHODS This cross-sectional study included 100 myopic children and 99 emmetropic children as a control group, ranging in age from 6 to 17 years. The Ocular Response Analyzer was used to measure corneal hysteresis (CH) and corneal resistance factor. The optic disc morphology and RNFL thickness were assessed using posterior segment optical coherence tomography (Cirrus HD-OCT). The axial length was measured using an IOLMaster, whereas the central corneal thickness was measured by anterior segment optical coherence tomography (Visante OCT). RESULTS The mean (±SD) age and spherical equivalent were 12.11 (±2.76) years and -3.32 (±2.32) diopters for the myopic group and 11.88 (±2.97) years and +0.34 (±0.41) diopters for the emmetropic group. In a multivariable mixed-model analysis in myopic children, the average RNFL thickness and rim area correlated positively with CH (p = 0.007 and p = 0.001, respectively), whereas the average cup-to-disc area ratio correlated negatively with CH (p = 0.01). We did not observe correlation between RNFL thickness and axial length (p = 0.05). Corneal resistance factor was only positively correlated with the rim area (p = 0.001). The central corneal thickness did not correlate with the optic nerve parameters or with RNFL thickness. These associations were not found in the emmetropic group (p > 0.05 for all). CONCLUSIONS The corneal biomechanics characterized with the Ocular Response Analyzer system are correlated with the optic disc profile and RNFL thickness in myopic children. Low CH values may indicate a reduction in the viscous dampening properties of the cornea and the sclera, especially in myopic children.
Collapse
|
36
|
Abstract
<p align="justify"><em>Objetivo</em>: cuantificar los parámetros biométricos oculares, las propiedades biomecánicas corneales, la configuración anatómica del nervio óptico y la capa de fibras nerviosas de la retina (CFNR) en un grupo de niños, mediante técnicas no invasivas. <em>Material y métodos</em>: se realizó un estudio transversal, descriptivo y no aleatorio en 293 niños sanos caucásicos con edades entre 6 y 17 años. <em>Resultados</em>: se encontró una correlación estadísticamente significativa entre la longitud axial (LA) y la histéresis corneal (CH) (p < 0,001). También se encontró disminución de la CH con el incremento de la miopía y el aumento de esta con el incremento de la hipermetropía (p < 0,001). En el segmento posterior, se evidenció correlación positiva entre el espesor medio de la CFNR y la CH (p = 0,01). Asimismo, se apreció disminución del espesor medio de la CFNR con el incremento de la LA (p < 0,001) y de la miopía (p < 0,0001). <em>Conclusiones</em>: la resistencia mecánica del segmento anterior del ojo está comprometida en miopes en edades tempranas y en miopías elevadas, independientemente de la edad. Valores más bajos de CH, además de una reducción en la capacidad de amortiguación viscoelástica corneal, indican la existencia de un nervio óptico más fácilmente deformable, acompañado de un adelgazamiento de la CFNR, sobre todo en niños miopes. Este estudio permite dar unos valores de normalidad de dichos parámetros y correlacionarlos con los errores refractivos.</p>
Collapse
|
37
|
Roberts CJ, Reinstein DZ, Archer TJ, Mahmoud AM, Gobbe M, Lee L. Comparison of ocular biomechanical response parameters in myopic and hyperopic eyes using dynamic bidirectional applanation analysis. J Cataract Refract Surg 2014; 40:929-36. [PMID: 24857439 DOI: 10.1016/j.jcrs.2014.04.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 12/18/2013] [Accepted: 01/07/2014] [Indexed: 11/30/2022]
Abstract
PURPOSE To compare differences in the ocular biomechanical response in myopic and hyperopic eyes. SETTING London Vision Clinic, London, United Kingdom, The Ohio State University, Columbus, OH, United States. DESIGN Retrospective study. METHODS The study population included myopic and hyperopic patients evaluated preoperatively for refractive surgery at the London Vision Clinic between June 2006 and May 2008. Biomechanical response parameters from the dynamic bidirectional applanation device (Ocular Response Analyzer) were analyzed using custom software for signal analysis, including corneal hysteresis (CH) and 10 other output parameters. Hyperopic eyes were compared with myopic eyes first matched for age and pachymetry and then matched for age, pachymetry, and corneal-compensated intraocular pressure (IOPcc). Nonpaired t tests were performed (P<.05) to compare parameters in the 2 groups. RESULTS Consecutive patients included 2608 eyes with 1623 myopic eyes and 787 hyperopic eyes that met enrollment criteria. A significant correlation (P<.0001) was shown between CH and age (negative), pachymetry (positive), and IOPcc (negative). The first match included 473 eyes in each group, and the second match included 260 eyes in each group. When matching for age and pachymetry only, certain parameters implied that hyperopic eyes were stiffer, while others implied that myopic eyes were stiffer, but IOPcc was significantly greater in the myopic group. The second match, which also controlled for IOPcc, showed that all biomechanical parameters implied that hyperopic eyes were stiffer. CONCLUSIONS Hyperopic eyes demonstrated stiffer response parameters than myopic eyes. Intraocular pressure was demonstrated to be a confounding factor when evaluating ocular biomechanical parameters. FINANCIAL DISCLOSURES Proprietary or commercial disclosures are listed after the references.
Collapse
Affiliation(s)
- Cynthia J Roberts
- From the Department of Ophthalmology and the Department of Biomedical Engineering (Roberts, Mahmoud), and the College of Medicine (Lee), The Ohio State University, Columbus, Ohio; the Department of Ophthalmology (Reinstein), Columbia University Medical Center, New York, New York, USA; the London Vision Clinic (Reinstein, Archer, Gobbe), London, United Kingdom; the Centre Hospitalier National d'Ophtalmologie (Reinstein), Paris, France
| | - Dan Z Reinstein
- From the Department of Ophthalmology and the Department of Biomedical Engineering (Roberts, Mahmoud), and the College of Medicine (Lee), The Ohio State University, Columbus, Ohio; the Department of Ophthalmology (Reinstein), Columbia University Medical Center, New York, New York, USA; the London Vision Clinic (Reinstein, Archer, Gobbe), London, United Kingdom; the Centre Hospitalier National d'Ophtalmologie (Reinstein), Paris, France.
| | - Timothy J Archer
- From the Department of Ophthalmology and the Department of Biomedical Engineering (Roberts, Mahmoud), and the College of Medicine (Lee), The Ohio State University, Columbus, Ohio; the Department of Ophthalmology (Reinstein), Columbia University Medical Center, New York, New York, USA; the London Vision Clinic (Reinstein, Archer, Gobbe), London, United Kingdom; the Centre Hospitalier National d'Ophtalmologie (Reinstein), Paris, France
| | - Ashraf M Mahmoud
- From the Department of Ophthalmology and the Department of Biomedical Engineering (Roberts, Mahmoud), and the College of Medicine (Lee), The Ohio State University, Columbus, Ohio; the Department of Ophthalmology (Reinstein), Columbia University Medical Center, New York, New York, USA; the London Vision Clinic (Reinstein, Archer, Gobbe), London, United Kingdom; the Centre Hospitalier National d'Ophtalmologie (Reinstein), Paris, France
| | - Marine Gobbe
- From the Department of Ophthalmology and the Department of Biomedical Engineering (Roberts, Mahmoud), and the College of Medicine (Lee), The Ohio State University, Columbus, Ohio; the Department of Ophthalmology (Reinstein), Columbia University Medical Center, New York, New York, USA; the London Vision Clinic (Reinstein, Archer, Gobbe), London, United Kingdom; the Centre Hospitalier National d'Ophtalmologie (Reinstein), Paris, France
| | - Linden Lee
- From the Department of Ophthalmology and the Department of Biomedical Engineering (Roberts, Mahmoud), and the College of Medicine (Lee), The Ohio State University, Columbus, Ohio; the Department of Ophthalmology (Reinstein), Columbia University Medical Center, New York, New York, USA; the London Vision Clinic (Reinstein, Archer, Gobbe), London, United Kingdom; the Centre Hospitalier National d'Ophtalmologie (Reinstein), Paris, France
| |
Collapse
|
38
|
Hashemi H, Jafarzadehpur E, Mehravaran S, Yekta A, Ostadimoghaddam H, Norouzirad R, Khabazkhoob M. Corneal resistance factor and corneal hysteresis in a 6- to 18-year-old population. J Cataract Refract Surg 2014; 40:1446-53. [PMID: 25135536 DOI: 10.1016/j.jcrs.2013.12.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Revised: 12/11/2013] [Accepted: 12/17/2013] [Indexed: 11/16/2022]
Abstract
PURPOSE To determine the distribution and normal range of the corneal resistance factor (CRF) and corneal hysteresis (CH) in the 6- to 18-year age range and their relationship with biometric components. SETTING Dezful, Iran. DESIGN Cross-sectional study. METHODS This study of Dezful school children used a multistage, stratified, cluster approach sampling. All students had examinations for biometry, noncycloplegic refraction, and corneal biomechanical properties; the examinations were performed in the same order in all cases. RESULTS Of the 864 selected students, 683 participated in the study. The mean CRF and CH was 11.74 mm Hg±1.77 (SD) (95% confidence interval [CI], 11.58-11.89) and 11.49±1.91 mm Hg (95% CI, 11.33-11.65), respectively. In a linear multiple regression model, the CRF significantly correlated with female sex (β coefficient=0.488, P=.013), central corneal thickness (CCT) (β coefficient=.034, P=.001), and keratometry (β-coefficient=0.157, P=.003) and CH significantly correlated with CCT (β coefficient=0.025, P<.001), axial length (β coefficient=-0.303, P=.011), and keratometry (β coefficient=0.11, P=.043). Each year increase in age was associated with a 42-unit decrease in the peak 1 area (P=.003). CONCLUSIONS The distribution of CRF and CH in an Iranian population was symmetrical and bell shaped. However, the CRF did not have a normal distribution. The mean CRF and CH were higher than those reported in almost all previous studies. FINANCIAL DISCLOSURE No author has a financial or proprietary interest in any material or method mentioned.
Collapse
Affiliation(s)
- Hassan Hashemi
- From the Noor Ophthalmology Research Center (Hashemi, Jafarzadehpur, Mehravaran), Noor Eye Hospital, and the Department of Optometry (Jafarzadehpur), Iran University of Medical Sciences, the Department of Epidemiology (Khabazkhoob) Faculty of Public Health, Shahid Beheshti University of Medical Sciences, Tehran, the Refractive Errors Research Center (Yekta, Ostadimoghaddam) and the Department of Optometry (Yekta, Ostadimoghaddam), School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, and the Dezful University of Medical Sciences (Norouzirad), Dezful, Iran
| | - Ebrahim Jafarzadehpur
- From the Noor Ophthalmology Research Center (Hashemi, Jafarzadehpur, Mehravaran), Noor Eye Hospital, and the Department of Optometry (Jafarzadehpur), Iran University of Medical Sciences, the Department of Epidemiology (Khabazkhoob) Faculty of Public Health, Shahid Beheshti University of Medical Sciences, Tehran, the Refractive Errors Research Center (Yekta, Ostadimoghaddam) and the Department of Optometry (Yekta, Ostadimoghaddam), School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, and the Dezful University of Medical Sciences (Norouzirad), Dezful, Iran
| | - Shiva Mehravaran
- From the Noor Ophthalmology Research Center (Hashemi, Jafarzadehpur, Mehravaran), Noor Eye Hospital, and the Department of Optometry (Jafarzadehpur), Iran University of Medical Sciences, the Department of Epidemiology (Khabazkhoob) Faculty of Public Health, Shahid Beheshti University of Medical Sciences, Tehran, the Refractive Errors Research Center (Yekta, Ostadimoghaddam) and the Department of Optometry (Yekta, Ostadimoghaddam), School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, and the Dezful University of Medical Sciences (Norouzirad), Dezful, Iran
| | - Abbasali Yekta
- From the Noor Ophthalmology Research Center (Hashemi, Jafarzadehpur, Mehravaran), Noor Eye Hospital, and the Department of Optometry (Jafarzadehpur), Iran University of Medical Sciences, the Department of Epidemiology (Khabazkhoob) Faculty of Public Health, Shahid Beheshti University of Medical Sciences, Tehran, the Refractive Errors Research Center (Yekta, Ostadimoghaddam) and the Department of Optometry (Yekta, Ostadimoghaddam), School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, and the Dezful University of Medical Sciences (Norouzirad), Dezful, Iran
| | - Hadi Ostadimoghaddam
- From the Noor Ophthalmology Research Center (Hashemi, Jafarzadehpur, Mehravaran), Noor Eye Hospital, and the Department of Optometry (Jafarzadehpur), Iran University of Medical Sciences, the Department of Epidemiology (Khabazkhoob) Faculty of Public Health, Shahid Beheshti University of Medical Sciences, Tehran, the Refractive Errors Research Center (Yekta, Ostadimoghaddam) and the Department of Optometry (Yekta, Ostadimoghaddam), School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, and the Dezful University of Medical Sciences (Norouzirad), Dezful, Iran
| | - Reza Norouzirad
- From the Noor Ophthalmology Research Center (Hashemi, Jafarzadehpur, Mehravaran), Noor Eye Hospital, and the Department of Optometry (Jafarzadehpur), Iran University of Medical Sciences, the Department of Epidemiology (Khabazkhoob) Faculty of Public Health, Shahid Beheshti University of Medical Sciences, Tehran, the Refractive Errors Research Center (Yekta, Ostadimoghaddam) and the Department of Optometry (Yekta, Ostadimoghaddam), School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, and the Dezful University of Medical Sciences (Norouzirad), Dezful, Iran
| | - Mehdi Khabazkhoob
- From the Noor Ophthalmology Research Center (Hashemi, Jafarzadehpur, Mehravaran), Noor Eye Hospital, and the Department of Optometry (Jafarzadehpur), Iran University of Medical Sciences, the Department of Epidemiology (Khabazkhoob) Faculty of Public Health, Shahid Beheshti University of Medical Sciences, Tehran, the Refractive Errors Research Center (Yekta, Ostadimoghaddam) and the Department of Optometry (Yekta, Ostadimoghaddam), School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, and the Dezful University of Medical Sciences (Norouzirad), Dezful, Iran.
| |
Collapse
|
39
|
In vivo characterization of corneal biomechanics. J Cataract Refract Surg 2014; 40:870-87. [DOI: 10.1016/j.jcrs.2014.03.021] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 11/12/2013] [Accepted: 11/15/2013] [Indexed: 11/22/2022]
|
40
|
Wong YZ, Lam AKC. The Roles of Cornea and Axial Length in Corneal Hysteresis among Emmetropes and High Myopes: A Pilot Study. Curr Eye Res 2014; 40:282-9. [DOI: 10.3109/02713683.2014.922193] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|
41
|
|
42
|
Corneal biomechanical properties in different ocular conditions and new measurement techniques. ISRN OPHTHALMOLOGY 2014; 2014:724546. [PMID: 24729900 PMCID: PMC3960740 DOI: 10.1155/2014/724546] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2013] [Accepted: 11/26/2013] [Indexed: 12/04/2022]
Abstract
Several refractive and therapeutic treatments as well as several ocular or systemic diseases might induce changes in the mechanical resistance of the cornea. Furthermore, intraocular pressure measurement, one of the most used clinical tools, is also highly dependent on this characteristic. Corneal biomechanical properties can be measured now in the clinical setting with different instruments. In the present work, we review the potential role of the biomechanical properties of the cornea in different fields of ophthalmology and visual science in light of the definitions of the fundamental properties of matter and the results obtained from the different instruments available. The body of literature published so far provides an insight into how the corneal mechanical properties change in different sight-threatening ocular conditions and after different surgical procedures. The future in this field is very promising with several new technologies being applied to the analysis of the corneal biomechanical properties.
Collapse
|
43
|
del Buey MA, Lavilla L, Ascaso FJ, Lanchares E, Huerva V, Cristóbal JA. Assessment of corneal biomechanical properties and intraocular pressure in myopic spanish healthy population. J Ophthalmol 2014; 2014:905129. [PMID: 24719755 PMCID: PMC3955599 DOI: 10.1155/2014/905129] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Accepted: 01/10/2014] [Indexed: 11/17/2022] Open
Abstract
Purpose. To examine biomechanical parameters of the cornea in myopic eyes and their relationship with the degree of myopia in a western healthy population. Methods. Corneal hysteresis (CH), corneal resistance factor (CRF), Goldmann correlated intraocular pressure (IOP), and corneal compensated IOP (IOPcc) were measured using the ocular response analyzer (ORA) in 312 eyes of 177 Spanish subjects aged between 20 and 56 years. Refraction was expressed as spherical equivalent (SE), which ranged from 0 to -16.50 diopters (D) (mean: -3.88 ± 2.90 D). Subjects were divided into four groups according to their refractive status: group 1 or control group: emmetropia (-0.50 ≤ SE < 0.50); group 2: low myopia (-0.75 ≤ SE < 3.00 D); group 3: moderate myopia (-3.00 ≤ SE ≤ -6.00 D); and group 3: high myopia (SE greater than -6.00 D). We analyzed the relationship between corneal biomechanics measured with ORA and SE. Results. CH in the emmetropia, low myopia, moderate myopia, and high myopia groups was 11.13 ± 0.98, 11.49 ± 1.25, 10.52 ± 1.54, and 10.35 ± 1.33 mmHg, respectively. CH in the highly myopic group was significantly lower than that in the emmetropic group (P = 0.07) and low myopic group (P = 0.035); however, there were no differences with the moderate myopic group (P = 0.872). There were no statistically significant differences regarding IOP among the four groups (P > 0.05); nevertheless, IOPcc was significantly higher in the moderately myopic (15.47 ± 2.47 mmHg) and highly myopic (16.14 ± 2.59 mmHg) groups than in the emmetropia (15.15 ± 2.06 mmHg) and low myopia groups (14.53 ± 2.37 mmHg). No correlation between age and the measured parameters was found. CH and IOPcc were weakly but significantly correlated with SE (r = 0.171, P = 0.002 and r = -0.131, P = 0.021, resp.). Conclusions. Present study showed only a very weak, but significant, correlation between CH and refractive error, with CH being lower in both moderately and highly myopic eyes than that in the emmetropic and low myopic eyes. These changes in biomechanical properties of the cornea may have an impact on IOP measurement, increasing the risk of glaucoma.
Collapse
Affiliation(s)
- María A. del Buey
- Department of Ophthalmology, Lozano Blesa University Clinic Hospital, Zaragoza, Spain
- Department of Ophthalmology, Quirón University Hospital, Zaragoza, Spain
- Instituto Aragonés de Ciencias de la Salud (IACS), Zaragoza, Spain
| | - Laura Lavilla
- Department of Ophthalmology, Lozano Blesa University Clinic Hospital, Zaragoza, Spain
- Department of Ophthalmology, Quirón University Hospital, Zaragoza, Spain
| | - Francisco J. Ascaso
- Department of Ophthalmology, Lozano Blesa University Clinic Hospital, Zaragoza, Spain
- Instituto Aragonés de Ciencias de la Salud (IACS), Zaragoza, Spain
| | - Elena Lanchares
- Instituto Aragonés de Ciencias de la Salud (IACS), Zaragoza, Spain
- Aragón Institute for Engineering Research (I3A), University of Zaragoza, CIBER on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Zaragoza, Spain
| | - Valentín Huerva
- Department of Ophthalmology, Arnau de Vilanova University Hospital and IRB-Lleida, Avenida Rovira Roure 80, Lleida, Spain
| | - José A. Cristóbal
- Department of Ophthalmology, Lozano Blesa University Clinic Hospital, Zaragoza, Spain
- Department of Ophthalmology, Quirón University Hospital, Zaragoza, Spain
- Instituto Aragonés de Ciencias de la Salud (IACS), Zaragoza, Spain
| |
Collapse
|
44
|
Ventura BV, Machado AP, Ambrósio R, Ribeiro G, Araújo LN, Luz A, Lyra JM. Analysis of waveform-derived ORA parameters in early forms of keratoconus and normal corneas. J Refract Surg 2013; 29:637-43. [PMID: 24016349 DOI: 10.3928/1081597x-20130819-05] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Accepted: 05/13/2013] [Indexed: 11/20/2022]
Abstract
PURPOSE To evaluate the Ocular Response Analyzer (ORA; Reichert Ophthalmic Instruments, Depew, NY) performance in differentiating grades I and II keratoconus from normal corneas using 41 parameters individually and to assess the effect of analyzing all parameters together. METHODS This study compared the mean value of 41 ORA parameters in grades I and II keratoconus with healthy age-matched control eyes. Only eyes with a central corneal thickness between 500 and 600 μm were included. The area under the receiver operating characteristic curve was calculated for each of the 41 parameters independently and for all of the parameters together. RESULTS This study included 136 eyes with normal corneas and 68 eyes with grades I and II keratoconus. When analyzed individually, four ORA parameters (p1area, p1area1, p2area, and p2area1) had an area under the curve greater than 0.900 for discriminating between both groups. The p2area was the parameter that achieved the largest area under the curve individually (0.931). The area under the curve increased to 0.978 when analyzing all parameters together. CONCLUSION Alternative ORA parameters are better for differentiating grades I and II keratoconus from normal corneas than the four parameters originally available for ophthalmologists (corneal hysteresis, Goldmann-correlated intraocular pressure, corneal-compensated intraocular pressure, and corneal resistance factor). Although the ORA did not achieve 100% accuracy, the discrimination between these two groups was optimized by combining all parameters.
Collapse
Affiliation(s)
- Bruna V Ventura
- Brazilian Study Group of Artificial Intelligence, Maceio, Rio de Janeiro, Brazil.
| | | | | | | | | | | | | |
Collapse
|
45
|
The biomechanical properties of the cornea and anterior segment parameters. BMC Ophthalmol 2013; 13:49. [PMID: 24083664 PMCID: PMC3852860 DOI: 10.1186/1471-2415-13-49] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Accepted: 09/25/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND To investigate the biomechanical properties of the cornea measured with the Ocular Response Analyzer (ORA) and their association with the anterior segment parameters representing the geometric dimensions including the corneal volume and anterior chamber volume. METHODS A retrospective review of 1020 patients who visited the BGN Eye Clinic was done. The mean radius of the corneal curvature, corneal astigmatism, corneal volume, anterior chamber depth, and anterior chamber volume were measured with an anterior segment tomographer. The central corneal thickness (CCT) was measured with an ultrasonic pachymeter. The corneal diameter was measured with an Orbscan as White to White. Cornea hysteresis (CH), corneal resistance factor (CRF), Goldmann correlated intraocular pressure (IOPg), and cornea-compensated IOP (IOPcc) were measured with an ORA. Multiple linear regression models were constructed with CH and CRF as the dependent variables and age, gender, and the anterior segment parameters as the covariates. RESULTS 958 eyes from 958 patients (mean age 26.7 years; male 43.4%) were included in this study after excluding some eyes according to the exclusion criteria. The mean CH and CRF were 10.1 and 9.9 mmHg, respectively. The mean IOPg and IOPcc were 14.8 and 15.8 mmHg. The multivariate analysis showed that CH was negatively associated with the mean radius of the cornea curvature (regression coefficient = -0.481, p = 0.023) and positively associated with CCT (regression coefficient = 0.015, p < 0.001) and corneal volume (regression coefficient =0.059, p = 0.014). The association between CH and the corneal diameter, anterior chamber depth, and anterior chamber volume were not statistically significant. The evaluation of CRF showed that CRF was negatively associated with the mean radius of the cornea curvature (regression coefficient = -0.540, p = 0.013), and positively associated with CCT (β = 0.026, p < 0.001). The association between CRF and the corneal diameter, corneal volume, anterior chamber depth, and anterior chamber volume were not statistically significant. CONCLUSION The CH was shown to be positively associated with the corneal volume and the association between CH and the anterior chamber volume were not significant. The associations of CRF with the corneal volume or anterior chamber volume were not significant.
Collapse
|
46
|
Kim KN, Jeoung JW, Park KH, Yang MK, Kim DM. Comparison of the new rebound tonometer with Goldmann applanation tonometer in a clinical setting. Acta Ophthalmol 2013; 91:e392-6. [PMID: 23521889 DOI: 10.1111/aos.12109] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
PURPOSE To evaluate the clinical usefulness of a new rebound tonometer, Icare(®) PRO (Icare PRO), by comparison with Goldmann applanation tonometry (GAT) in a study on patients with glaucoma. METHODS One hundred and seventy-two eyes of 86 subjects were enrolled in this study. All of the subjects were examined with an autorefractometer, Icare PRO, slit-lamp biomicroscope, GAT, ultrasound A-scan and pachymeter. Three intraocular pressure (IOP) measurements were obtained by Icare PRO and GAT. The intraobserver reliabilities were established by calculating the intraclass correlation coefficients. The Bland-Altman plot was used to compare the Icare PRO and GAT. RESULTS There was a good correlation between the IOP measurement by GAT and that by Icare PRO (r = 0.6995, p < 0.001). The intraclass correlation coefficients of Icare PRO and GAT were 0.778 and 0.955, respectively. The IOP differences between Icare PRO and GAT (mean: 1.92 mmHg; SD: 3.29 mmHg; 95% limit of agreement: -4.52 to 8.37 mmHg) did not vary over the wide range of central corneal thickness (p = 0.498), age (p = 0.248), axial length (p = 0.277) or spherical equivalent (p = 0.075). CONCLUSIONS Although IOP with Icare PRO was higher than that with GAT, especially at lower GAT IOP value, Icare PRO was found to be a reliable method and showed a good correlation with GAT. The IOP difference between Icare PRO and GAT was not affected by the central corneal thickness, age, axial length or spherical equivalent. Icare PRO can be expected not only to be a good screening tool but also to be a good substitute for GAT.
Collapse
Affiliation(s)
- Kyoung Nam Kim
- Department of Ophthalmology, Seoul National University Hospital, Seoul, Korea
| | | | | | | | | |
Collapse
|
47
|
Ruiseñor Vázquez PR, Delrivo M, Bonthoux FF, Pförtner T, Galletti JG. Combining ocular response analyzer metrics for corneal biomechanical diagnosis. J Refract Surg 2013; 29:596-602. [PMID: 23848186 DOI: 10.3928/1081597x-20130710-01] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2012] [Accepted: 04/25/2013] [Indexed: 11/20/2022]
Abstract
PURPOSE To evaluate corneal biomechanical properties in non-keratoconic myopic eyes and to identify descriptors for improving the specificity of the Ocular Response Analyzer (ORA) (Reichert Ophthalmic Instruments, Depew, NY) testing for subclinical keratoconus detection. METHODS Observational case series of 52 non-keratoconic non-myopic eyes and 97 non-keratoconic myopic eyes (spherical equivalent < -5 diopters [D]) in dataset 1 and 87 non-keratoconic eyes and 73 eyes with subclinical keratoconus in dataset 2. Examination included corneal topography, tomography, and biomechanical testing with the ORA. Receiver operating characteristic curves and logistic regression were used to identify optimal combinations of biomechanical indices for keratoconus detection. Main outcome measures were corneal thickness-corrected hysteresis (DifCH) and resistance factor (DifCRF), the difference between these two (CH-CRF), and the diagnostic performance of their combinations. RESULTS Compared to non-keratoconic non-myopic eyes, non-keratoconic myopic eyes with flat corneas (average corneal power < 44.0 D) had reduced DifCH (mean ± standard deviation, 0.11 ± 1.27 vs -0.79 ± 1.50, P < .01) and DifCRF (0.24 ± 1.16 vs -0.70 ± 1.59, P < .01) values, whereas non-keratoconic myopic eyes with steep corneas showed no difference. Keratoconic eyes exhibited lower DifCH and DifCRF values than non-keratoconic myopic eyes. Combinations of DifCH, DifCRF, and CH-CRF had increased specificity (> 80%) for subclinical keratoconus compared to the DifCRF index alone (71%). CONCLUSIONS In biomechanical keratoconus screening, some non-keratoconic myopic eyes show altered ocular biomechanical properties and are identified as false-positive cases. The low specificity of DifCRF when dealing with these non-keratoconic eyes could be improved by considering additional biomechanical descriptors such as DifCH and CH-CRF, which seem to be indicative of the aforementioned biomechanical profile.
Collapse
|
48
|
Abstract
PURPOSE To describe intraocular pressure (IOP) and central corneal thickness (CCT) in ethnically diverse, myopic young adults enrolled in COMET (the Correction of Myopia Evaluation Trial) and their association with ocular and demographic factors. METHODS IOP (Goldmann tonometry), CCT (handheld pachymetry), refractive error (cycloplegic autorefraction), and ocular components (A-scan ultrasonography) were measured in 385 of the original 469 subjects (mean age = 20.3 ± 1.3 years). Summary statistics for descriptive analysis, Pearson correlation coefficients, and linear regression models to formally test the association of IOP and CCT with other covariates were used. RESULTS Mean IOP was 15.1 ± 0.1 mm Hg and differed by ethnicity and CCT but did not vary by gender, magnitude of myopia, or vitreous chamber depth (VCD). Adjusting for CCT, IOP in black participants was 1.8 mm Hg higher than in Hispanics (p = 0.0001) and 0.8 mm Hg higher than in whites (p = 0.03). Mean CCT was 562.4 ± 1.8 μm and differed by ethnicity, VCD, and IOP after adjusting for covariates. Blacks had thinner corneas than Asians, whites, and Hispanics, with adjusted differences of 15.4, 11.8, and 15.3 μm (p = 0.03, < 0.01 and < 0.01), respectively. Eyes with shorter VCD (<17.8 mm) had 8.0-μm thinner CCT (p = 0.03). CCT did not vary by gender or magnitude of myopia. Overall, a modest positive correlation (r = 0.25, P < 0.0001) was found between IOP and CCT, which varied by ethnicity in Asians (r = 0.47; p = 0.008), blacks (r = 0.29; p = 0.002), and whites (r = 0.24; p = 0.002). CONCLUSIONS Myopic, black young adults had higher IOP and thinner corneas relative to other ethnic groups, suggesting that evaluation of these parameters during routine examination of these individuals should begin at a young age. Their thinner CCT should also be considered in evaluations for refractive surgery.
Collapse
|
49
|
Rhew JY, Choi KR. Corneal Biomechanical Properties of Normal Tension Glaucoma in Young Patients Evaluated with the Ocular Response Analyzer. JOURNAL OF THE KOREAN OPHTHALMOLOGICAL SOCIETY 2013. [DOI: 10.3341/jkos.2013.54.2.280] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Jin Young Rhew
- Department of Ophthalmology, Ewha Womans University School of Medicine, Ewha Institute of Ophthalmology and Optometry, EIOO, Seoul, Korea
| | - Kyu Ryong Choi
- Department of Ophthalmology, Ewha Womans University School of Medicine, Ewha Institute of Ophthalmology and Optometry, EIOO, Seoul, Korea
| |
Collapse
|
50
|
Abstract
PURPOSE To evaluate the relative influences of several demographic, ocular, and systemic parameters on corneal hysteresis (CH). METHODS This is a prospective, observational, cross-sectional study using subjects recruited from consecutive Albuquerque VAMC eye clinic patients. We classified eligible subjects as primary open-angle glaucoma (POAG), ocular hypertension, glaucoma suspect, or normal. We used the Ocular Response Analyzer, Pascal Dynamic Contour Tonometer, and Goldmann applanation tonometer to obtain intraocular pressure (IOP), CH, corneal resistance factor, and ocular pulse amplitude values. We also obtained corneal curvature, central corneal thickness (CCT), axial length, retinal nerve fiber layer thickness, clinical cup/disc ratio (CDR) estimates, and standard automated perimetry metrics (mean defect, pattern standard deviation). We gathered glycosylated hemoglobin (A1C) data through chart review. Multivariate regression analyses were used to determine independent relationships between CH and the other parameters. RESULTS Three hundred seventeen eyes in 317 subjects were studied (116 POAG, 87 ocular hypertension, 47 glaucoma suspect, and 67 normal). In univariate regression analysis, CH varied directly with CCT (β = 0.39, p < 0.001), corneal curvature (β = 0.16, p = 0.01), corneal resistance factor (β = 0.57, p < 0.001), A1C (β = 0.15, p = 0.01), mean defect (β = 0.29, p < 0.001), and retinal nerve fiber layer (β = 0.31, p < 0.001). Factors inversely related to CH were age (β = -0.22, p < 0.001), IOP (β = -0.29, p < 0.001), ocular pulse amplitude (β = -0.11, p = 0.04), CDR (β = -0.34, p < 0.001), and pattern standard deviation (β = -0.29, p < 0.001). CH was lower in POAG compared with the other diagnostic groups. In multivariate analysis, CH was independently associated with age, IOP, CCT, A1C, glaucoma diagnosis, and CDR. Of these factors, CCT and IOP demonstrated twice as much influence on CH compared with the other four factors. CONCLUSIONS Although this study identified six separate variables that independently influence CH values, the overall r value indicates that these variables together only explain 40% of CH variability. These results suggest that other significant sources of variability exist and deserve investigation.
Collapse
|