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Lu W, Ding W, Ji R, Tian Y, Zhao C, Li H, Jiao M, Guo Z, Leng L. Repeatability and correlation of corneal biomechanical measurements obtained by Corvis ST in orthokeratology patients. Cont Lens Anterior Eye 2022; 46:101793. [PMID: 36509642 DOI: 10.1016/j.clae.2022.101793] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 12/02/2022] [Accepted: 12/04/2022] [Indexed: 12/14/2022]
Abstract
PURPOSE To evaluate the repeatability of the corneal biomechanical measurements obtained by Corvis ST in post-orthokeratology patients and analyze the correlation between the biomechanical and ocular parameters. METHODS Fifty-one eyes of 51 myopic subjects were included in this study. The biomechanical parameters were assessed using Corvis ST. Repeatability was assessed using one-way ANOVA based on within-subject standard deviation (Sw), repeatability coefficient (RC), intraclass correlation coefficient (ICC) and correlation of variation (CoV). The correlation was evaluated using Pearson correlation analysis. RESULTS All parameters measured by Corvis ST, except length of flattened cornea at the first and second applanations (A1L and A2L), showed a good intraobserver repeatability after a 3-month follow-up period. The ICC values for A1L and A2L were 0.444 and 0.654, whereas the other parameters were higher than 0.8. Similar trends were obtained for CoV, wherein the CoV values for A1L and A2L were greater than 13 %. The corneal biomechanical parameters were correlated with age, refraction, axial length (AL), steep and flat keratometry before and after orthokeratology, and central corneal thickness (CCT). Following orthokeratology treatment, post-keratometry demonstrated a higher correlation with stiffness parameter at first applanation (SP-A1), velocity of corneal apex at the first applanation (A1V), and radius than pre-keratometry, which showed a weak correlation with SP-A1. CONCLUSION Corneal biomechanical parameters assessed using Corvis ST demonstrated a good repeatability, except A1L and A2L. The corneal biomechanical parameters were correlated with age, refraction, AL and pre- and post-keratometry. Thus, Corvis ST is a suitable device for investigating biomechanical parameter.
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Affiliation(s)
- Weicong Lu
- Eye Institute of Shandong First Medical University, Qingdao Eye Hospital of Shandong First Medical University, Shandong, China; State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong, China; School of Ophthalmology, Shandong First Medical University, Shandong, China
| | - Wenzhi Ding
- Eye Institute of Shandong First Medical University, Qingdao Eye Hospital of Shandong First Medical University, Shandong, China; State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong, China; School of Ophthalmology, Shandong First Medical University, Shandong, China
| | - Rongyuan Ji
- Eye Institute of Shandong First Medical University, Qingdao Eye Hospital of Shandong First Medical University, Shandong, China; State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong, China; School of Ophthalmology, Shandong First Medical University, Shandong, China
| | - Yuyin Tian
- Eye Institute of Shandong First Medical University, Qingdao Eye Hospital of Shandong First Medical University, Shandong, China; State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong, China; School of Ophthalmology, Shandong First Medical University, Shandong, China
| | - Chenpei Zhao
- Eye Institute of Shandong First Medical University, Qingdao Eye Hospital of Shandong First Medical University, Shandong, China; State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong, China; School of Ophthalmology, Shandong First Medical University, Shandong, China
| | - Honglei Li
- Eye Institute of Shandong First Medical University, Qingdao Eye Hospital of Shandong First Medical University, Shandong, China; State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong, China; School of Ophthalmology, Shandong First Medical University, Shandong, China
| | - Mengjun Jiao
- Eye Institute of Shandong First Medical University, Qingdao Eye Hospital of Shandong First Medical University, Shandong, China; State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong, China; School of Ophthalmology, Shandong First Medical University, Shandong, China
| | - Zhen Guo
- Eye Institute of Shandong First Medical University, Qingdao Eye Hospital of Shandong First Medical University, Shandong, China; State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong, China; School of Ophthalmology, Shandong First Medical University, Shandong, China
| | - Lin Leng
- Eye Institute of Shandong First Medical University, Qingdao Eye Hospital of Shandong First Medical University, Shandong, China; State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong, China; School of Ophthalmology, Shandong First Medical University, Shandong, China.
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Wan K, Cheung SW, Wolffsohn JS, Cho P. Repeatability of corneal biomechanics waveform signal parameters derived from Ocular Response Analyzer in children. Cont Lens Anterior Eye 2020; 44:101373. [PMID: 33268269 DOI: 10.1016/j.clae.2020.10.003] [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: 07/04/2020] [Revised: 09/29/2020] [Accepted: 10/05/2020] [Indexed: 10/23/2022]
Abstract
PURPOSE To investigate the repeatability of waveform signal parameters, measured with the Ocular Response Analyzer (ORA), in children. METHODS Two sets of ORA measurements, with a 10-min break between them, were performed on children, aged six to <11 years old, either wearing single-vision spectacles (SVS) or orthokeratology (ortho-k) lenses. Intraclass correlation coefficients (ICCs) were used to assess agreements between two sets of measurements (37 waveform signal parameters). Bland-Altman (BA) plots were used to further analyse waveform signal parameters which had ICC 95 % confidence interval (95 % CI) between 0.50 to >0.90 (regarded as moderate to excellent agreement). RESULTS A total of 30 participants [15 SVS, 15 ortho-k (3.6 ± 2.4 months)] completed the study. Since no significant between-group differences were detected in demographic data (p > 0.28) and all waveform signal parameters (p > 0.05), data from the two groups of participants were pooled for the analysis of repeatability. Six parameters, h2, h21, p1area, p1area1, p2area, and p2area1, achieved ICCs (95 % CI) of 0.82-0.85 (0.61-0.93). The mean (SD) of these six parameters were 372 (91), 248 (61), 4077 (854), 1762 (399), 2359 (670), and 1020 (300), respectively. Bland-Altman plots and 95 % limits of agreement (95 % LoA) showed considerable agreement for all six parameters, the mean difference (95 % LoA) were -3 (-101 to 94), -2 (-67.56-62.70), 111 (-723 to 946), 102 (-334 to 539), 25 (-718 to 768), and -3 (-350 to 343), respectively. CONCLUSIONS Six waveform signal parameters (h2, h21, p1area, p1area1, p2area, and p2area1), which represent or are related to the areas under the waveform at the peaks in the signal, had moderate to excellent agreement in children. Results of the current study provides fundamental information for further studies on the potential clinical application of these waveform signal parameters in children.
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Affiliation(s)
- Kin Wan
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hong Kong, China.
| | - Sin Wan Cheung
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hong Kong, China
| | | | - Pauline Cho
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hong Kong, China
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Wang X, Xu G, Wang W, Wang J, Chen L, He M, Chen Z. Changes in corneal biomechanics in patients with diabetes mellitus: a systematic review and meta-analysis. Acta Diabetol 2020; 57:973-981. [PMID: 32201905 DOI: 10.1007/s00592-020-01481-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 01/10/2020] [Indexed: 02/07/2023]
Abstract
AIMS To determine the changes in corneal biomechanical parameters in patients with diabetes mellitus (DM) in comparison with controls. METHODS Pertinent studies were identified by comprehensively search of PubMed, Embase, the Web of Science, the Cochrane Library, Scopus, the China National Knowledge Infrastructure and the Chinese biomedical disc (CBM) databases. Pooling analyses by random models using the D-L method were performed for corneal hysteresis (CH), the corneal resistance factor (CRF), corneal-compensated intraocular pressure (IOPcc) and Goldmann-correlated intraocular pressure (IOPg). RESULTS A total of 15 studies were included in the final analysis, involving 1506 eyes in the diabetic group and 2190 eyes in the control group. The diabetic group had significantly higher CH, CRF, IOPg and IOPcc values than the control group. The pooled mean differences were 1.34 mmHg (95% confidence interval [CI] 0.60-2.08 mmHg, P < 0.001) for IOPg and 0.85 mmHg (95% CI 0.18-1.51 mmHg, P = 0.013) for IOPcc, 0.38 mmHg (95% CI 0.01-0.75, P = 0.047) for CH and 0.63 mmHg (95% CI 0.27-0.98, P = 0.001) for the CRF. Sensitivity analyses using the leave-one-out method showed a consistent significant difference between the groups (all P < 0.001). CONCLUSIONS Corneal biomechanics changed in the patients with DM. High CH, CRF, IOPcc and IOPg values may be associated factors for diabetes mellitus. Future studies are warranted to clarify the underlying mechanisms and explore the relationship between corneal biomechanics, glaucoma and diabetes mellitus. REGISTRATION PROSPERO registration No CRD4201705465.
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Affiliation(s)
- Xiaoyi Wang
- Department of Ophthalmology Center, Huizhou Municipal Central Hospital, Huizhou, Guangdong Province, People's Republic of China
| | - Guihua Xu
- Department of Ophthalmology Center, Huizhou Municipal Central Hospital, Huizhou, Guangdong Province, People's Republic of China
| | - Wei Wang
- Zhongshan Ophthalmic Center, State Key Laboratory of Ophthalmology, Sun Yat-Sen University, Guangzhou, People's Republic of China
| | - Juanjuan Wang
- Department of Ophthalmology Center, Huizhou Municipal Central Hospital, Huizhou, Guangdong Province, People's Republic of China
| | - Lili Chen
- Department of Ophthalmology Center, Huizhou Municipal Central Hospital, Huizhou, Guangdong Province, People's Republic of China
| | - Mingguang He
- Zhongshan Ophthalmic Center, State Key Laboratory of Ophthalmology, Sun Yat-Sen University, Guangzhou, People's Republic of China
| | - Zilin Chen
- Department of Ophthalmology Center, Huizhou Municipal Central Hospital, Huizhou, Guangdong Province, People's Republic of China.
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Zhou J, Gao Y, Li S, Gu W, Wu L, Guo X. Predictors of Myopic Regression for Laser-assisted Subepithelial Keratomileusis and Laser-assisted in Situ Keratomileusis Flap Creation with Mechanical Microkeratome and Femtosecond Laser in Low and Moderate Myopia. Ophthalmic Epidemiol 2019; 27:177-185. [PMID: 31878825 DOI: 10.1080/09286586.2019.1704793] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Purpose: To determine the predictive factors of postoperative myopic regression in subjects who have undergone laser-assisted subepithelial keratomileusis (LASEK), laser-assisted in situ keratomileusis (LASIK) with flaps created using a mechanical microkeratome (MM) or LASIK with flaps created using a femtosecond (FS) laser for -0.50 D to -6.0 D myopia.Materials and Methods: This study was designed as a retrospective comparison. We included 236 eyes in the LASEK group, 1,178 eyes in the MM-LASIK group and 1,333 eyes in the FS-LASIK group. Refractive outcomes were recorded at one day; one week; and one, three, six and 12 months postoperatively. Predictors affecting myopic regression and other covariates were estimated using a Cox proportional hazards model for the three methods of surgery.Results: At 12 months, the survival rates (no myopic regression) were 63.36%, 74% and 77% in the MM-LASIK, LASEK, and FS-LASIK groups, respectively. Risk factors for myopic regression were indicated for patients with greater preoperative central corneal thicknesses (CCT) (P = .02), female patients (P < .01), patients with aspherical ablations (P = .01) and those with larger transitional zones (TZ) (P < .01). Among the three surgeries, MM-LASIK had a significantly higher probability of postoperative myopic regression (P < .01). Longer durations of myopia (P = .03), steeper corneal curvatures (Kmax) (P < .01) and larger optical zones (OZ) (P < .01) were protective factors.Conclusion: MM-LASIK had the highest risk for myopic regression. OZ, TZ, aspherical ablations, preoperative corneal curvatures and being a female patient had significant influence on myopic regression in -0.50 D to -6.0 D myopia.
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Affiliation(s)
- Jihong Zhou
- Beijing Aier-Intech Eye Hospital, Beijing, China.,School of Public Health, Capital Medical University, Beijing, China
| | - Yan Gao
- Beijing Aier-Intech Eye Hospital, Beijing, China
| | - Shaowei Li
- Beijing Aier-Intech Eye Hospital, Beijing, China
| | - Wei Gu
- Beijing Aier-Intech Eye Hospital, Beijing, China
| | - Lijuan Wu
- School of Public Health, Capital Medical University, Beijing, China
| | - Xiuhua Guo
- School of Public Health, Capital Medical University, Beijing, China
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Zhang B, Shweikh Y, Khawaja AP, Gallacher J, Bauermeister S, Foster PJ. Associations with Corneal Hysteresis in a Population Cohort: Results from 96 010 UK Biobank Participants. Ophthalmology 2019; 126:1500-1510. [PMID: 31471087 DOI: 10.1016/j.ophtha.2019.06.029] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 06/07/2019] [Accepted: 06/28/2019] [Indexed: 11/16/2022] Open
Abstract
PURPOSE To describe the distribution of corneal hysteresis (CH) in a large cohort and explore its associated factors and possible clinical applications. DESIGN Cross-sectional study within the UK Biobank, a large cohort study in the United Kingdom. PARTICIPANTS We analyzed CH data from 93 345 eligible participants in the UK Biobank cohort, aged 40 to 69 years. METHODS All analyses were performed using left eye data. Linear regression models were used to evaluate associations between CH and demographic, lifestyle, ocular, and systemic variables. Piecewise logistic regression models were used to explore the relationship between self-reported glaucoma and CH. MAIN OUTCOME MEASURES Corneal hysteresis (mmHg). RESULTS The mean CH was 10.6 mmHg (10.4 mmHg in male and 10.8 mmHg in female participants). After adjusting for covariables, CH was significantly negatively associated with male sex, age, black ethnicity, self-reported glaucoma, diastolic blood pressure, and height. Corneal hysteresis was significantly positively associated with smoking, hyperopia, diabetes, systemic lupus erythematosus (SLE), greater deprivation (Townsend index), and Goldmann-correlated intraocular pressure (IOPg). Self-reported glaucoma and CH were significantly associated when CH was less than 10.1 mmHg (odds ratio, 0.86; 95% confidence interval, 0.79-0.94 per mmHg CH increase) after adjusting for covariables. When CH exceeded 10.1 mmHg, there was no significant association between CH and self-reported glaucoma. CONCLUSIONS In our analyses, CH was significantly associated with factors including age, sex, and ethnicity, which should be taken into account when interpreting CH values. In our cohort, lower CH was significantly associated with a higher prevalence of self-reported glaucoma when CH was less than 10.1 mmHg. Corneal hysteresis may serve as a biomarker aiding glaucoma case detection.
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Affiliation(s)
- Bing Zhang
- Department of Psychiatry, University of Oxford, Oxford, United Kingdom
| | - Yusrah Shweikh
- National Institute for Health Research Biomedical Research Centre, Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom; UCL Institute of Ophthalmology, London, United Kingdom
| | - Anthony P Khawaja
- National Institute for Health Research Biomedical Research Centre, Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom; UCL Institute of Ophthalmology, London, United Kingdom
| | - John Gallacher
- Department of Psychiatry, University of Oxford, Oxford, United Kingdom
| | | | - Paul J Foster
- National Institute for Health Research Biomedical Research Centre, Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom; UCL Institute of Ophthalmology, London, United Kingdom.
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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.
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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
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Sayed MS, Lee RK. Corneal Biomechanical Properties and Their Role in Glaucoma Diagnosis and Management. Int Ophthalmol Clin 2018; 58:35-49. [PMID: 29870409 DOI: 10.1097/iio.0000000000000233] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Sedaghat MR, Ostadi-Moghadam H, Jabbarvand M, Askarizadeh F, Momeni-Moghaddam H, Narooie-Noori F. Corneal hysteresis and corneal resistance factor in pellucid marginal degeneration. J Curr Ophthalmol 2017; 30:42-47. [PMID: 29564407 PMCID: PMC5859559 DOI: 10.1016/j.joco.2017.08.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 07/02/2017] [Accepted: 08/01/2017] [Indexed: 01/09/2023] Open
Abstract
Purpose To evaluate and compare corneal hysteresis (CH) and corneal resistance factor (CRF) in pellucid marginal degeneration (PMD), keratoconus (KCN), and normal eyes using the Ocular Response Analyzer (ORA). Methods In this retrospective study, corneal biomechanical parameters were measured in patients with PMD (n = 102) and KCN (n = 202) and normal subjects (n = 208) using the ORA. Data, including full patient history as well as the results of refraction, slit-lamp biomicroscopy, Pentacam HR (Oculus), and ORA (Reichert; Buffalo, New York, USA), were collected from medical records. Also, the data of only one eye per individual were selected for the analysis. The inclusion criteria for PMD and KCN groups were a reliable diagnosis of these ectatic disorders based on the clinical and corneal tomographic findings. CH, CRF, CH–CRF, intraocular pressure (IOP) measurements were assessed for each subject. Data were analyzed with SPSS and MedCalc using the ANOVA, Pearson Correlation, and receiver operating characteristic (ROC) curve analysis. Results The mean CH was 8.91 mmHg ± 1.05 [standard deviation (SD)], 8.43 ± 0.78, and 10.89 ± 1.08 in the PMD, KCN, and normal group, respectively. Also, the mean CRF was 8.21 ± 1.35, 7.19 ± 1.11, and 10.69 ± 1.41 in the PMD, KCN, and normal group, respectively. ANOVA showed differences in the mean CH, CRF, and CH–CRF between three groups (P < 0.001). Also, ROC curve analysis showed the cut-off points ≤9.5, ≤9.5, and >1.3 mmHg for CH, CRF, and CH–CRF in the PMD group, respectively. For biomechanical parameters in PMD eyes, CRF had the highest sensitivity (75.49%) while the greatest area under the ROC curve (AUC) was seen for CH (0.903). Moreover, central corneal thickness (CCT) showed no correlation with CH (P = 0.30, r = −0.104) or CRF (P = 0.75, r = 0.033) in the PMD group. Conclusions This study presented the values of corneal biomechanics for PMD using the ORA. The results of the ORA were markedly different between PMD, KCN, and normal eyes.
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Affiliation(s)
- Mohamad Reza Sedaghat
- Cornea Research Center, Khatam-Al-Anbia Hospital, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Hadi Ostadi-Moghadam
- 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
| | - Mahmoud Jabbarvand
- Ophthalmology Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Farshad Askarizadeh
- 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
| | - Hamed Momeni-Moghaddam
- 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
| | - Foroozan Narooie-Noori
- 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
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Naderan M, Jahanrad A. Anterior, posterior and biomechanical parameters of cornea during pregnancy in healthy eyes: a cohort study. Br J Ophthalmol 2017; 102:309-312. [PMID: 28756375 DOI: 10.1136/bjophthalmol-2017-310247] [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: 01/25/2017] [Revised: 06/18/2017] [Accepted: 07/01/2017] [Indexed: 11/03/2022]
Abstract
BACKGROUND To investigate the effect of pregnancy on anterior, posterior and biomechanical corneal parameters of healthy eyes. METHOD In this prospective cohort study, 70 pregnant participants with clinically healthy eyes underwent corneal topographic imaging evaluation by Pentacam and biomechanical assessment by Ocular Response Analyzer (ORA) before pregnancy, at the third trimester of pregnancy (34th week of pregnancy) and 12 months after delivery. The same number of age-matched non-pregnant females was evaluated at the corresponding appointments as the control group. RESULTS Assessment of the tomographic, topographic and ORA measurements before pregnancy, at the third trimester of pregnancy and 12 months post partum revealed no statistically significant changes in anterior and posterior corneal flat, steep and mean keratometry, anterior and posterior elevation measurements, central and thinnest corneal thickness, corneal hysteresis, corneal resistance factor and intraocular pressure measurements (p>0.05, repeated measures analysis of variance (ANOVA)). All of the study parameters returned to their baseline levels 1 year after delivery. The ophthalmic parameters of the non-pregnant group remained significantly unchanged during the study period (p>0.05, all comparisons, repeated measures ANOVA). Moreover, no statistically significant differences were found between pregnant and non-pregnant groups in the second (34th week of pregnancy) and third (post partum) appointments (p>0.05, all comparisons, one-way ANOVA). CONCLUSION Our findings may suggest a physiological nature for ocular changes during pregnancy that these changes return to baseline values after delivery. The differences between tomographic, topographic and biomechanical corneal parameters before pregnancy, during pregnancy and post partum were not statistically or clinically significant.
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Affiliation(s)
- Mohammad Naderan
- School of Medicine, Tehran University of Medical Sciences, Tehran, The Islamic Republic of Iran
| | - Ali Jahanrad
- AJA University of Medical Sciences, Tehran, The Islamic Republic of Iran
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Zimmermann M, Pitz S, Schmidtmann I, Pfeiffer N, Wasielica-Poslednik J. Tonographic Effect of Ocular Response Analyzer in Comparison to Goldmann Applanation Tonometry. PLoS One 2017; 12:e0169438. [PMID: 28068365 PMCID: PMC5221819 DOI: 10.1371/journal.pone.0169438] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 12/06/2016] [Indexed: 11/29/2022] Open
Abstract
Aims The tonographic effect is a phenomenon of intraocular pressure (IOP) reduction following repeated tonometry. This study examines whether the tonographic effect occurs following IOP measurement performed with Ocular Response Analyzer (ORA). Methods Both eyes of 31 glaucoma patients and 35 healthy controls underwent nine IOP-measurements performed with GAT and ORA. The number of GAT and ORA measurements performed on each eye differed depending on the randomly allocated investigation scheme. Central corneal thickness (CCT), anterior chamber volume (ACV) and anterior chamber depth (ACD) were assessed with Pentacam before and after the repeated GAT/ORA measurements. Results There was no statistically significant tonographic effect for IOP readings obtained by the ORA: corneal compensated intraocular pressure (IOPcc) (-0.11 ± 3.06 mmHg, p = 0.843 in patients and -0.71 ± 3.28 mmHg, p = 0.208 for controls) and Goldmann-correlated intraocular pressure (IOPg) (-0.31 ± 2.38 mmHg, p = 0.469 in patients and -0.31 ± 2.37 mmHg, p = 0.441 in controls) measured with ORA. There was a significant IOP reduction from the first to the second GAT measurement, i.e. tonographic effect (-0.55 ± 2.00 mmHg, p = 0.138 in patients and -1.15 ± 1.52 mmHg, p < 0.001 in controls). CCT, corneal hysteresis (CH) and corneal resistance factor (CRF) were lower in glaucoma patients. The repeated IOP measurements resulted in an increase of CCT in all subjects (but no change of ACV and ACD). The tonographic effect of GAT correlated with CCT in glaucoma patients (r = 0.37). Conclusion In contrast to GAT, repeated ORA measurements do not result in the tonographic effect. Repeated IOP measurements resulted in an increase of central corneal thickness, but did not influence the volume and depth of anterior chamber.
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Affiliation(s)
- Martin Zimmermann
- Department of Ophthalmology, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany
- * E-mail:
| | - Susanne Pitz
- Department of Ophthalmology, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Irene Schmidtmann
- Institute for Medical Biostatistics, Epidemiology and Informatics (IMBEI), University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Norbert Pfeiffer
- Department of Ophthalmology, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Joanna Wasielica-Poslednik
- Department of Ophthalmology, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany
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Repeatability, reproducibility, and age dependency of dynamic Scheimpflug-based pneumotonometer and its correlation with a dynamic bidirectional pneumotonometry device. Cornea 2015; 34:71-7. [PMID: 25393092 DOI: 10.1097/ico.0000000000000293] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To assess the repeatability, reproducibility, and age dependency of dynamic Scheimpflug-based pneumotonometry (Corvis)-generated parameters and their correlation with dynamic bidirectional pneumotonometry device [Ocular Response Analyzer (ORA)] measurements [corneal hysteresis (CH) and corneal resistance factor (CRF)]. METHODS Eyes of 29 healthy participants between 20 and 30 years old were measured using Corvis and ORA. Measurements were performed twice in a row and repeated after 1 week. Repeatability and reproducibility were examined by calculating intraday and interday coefficients of variation (CVs). Corvis measurements were compared with measurements from 19 participants older than 65 years. RESULTS The most repeatable and reproducible Corvis-generated parameters, with intraday and interday CVs < 10% were as follows: intraocular pressure (IOP), pachymetry, time to first and second applanation (A1 time, A2 time), radius and amplitude at highest concavity (HC radius and HC deformation amplitude, respectively), time to highest concavity (HC time), deflection length and amplitude at highest concavity [HC deflection length and HC deflection amplitude (millimeter), respectively], and time to highest deflection amplitude [HC deflection amplitude (millisecond)]. However, 7 of 19 analyzed parameters showed CVs > 10%. HC-related parameters showed significant age dependency. The correlation between Corvis and ORA was weak (A2 time and CH, r = 0.36, A1 time and CRF, r = 0.41). Corvis-derived IOP was on average 2.2 ± 2.3 mm Hg higher than cornea-compensated IOP, with large differences in patients with high-average IOP. CONCLUSIONS The considerable variation in repeatability and reproducibility should be taken into account when using the Corvis. Corvis parameters showed poor correlation with CH and CRF obtained by ORA measurements.
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Bao F, Deng M, Wang Q, Huang J, Yang J, Whitford C, Geraghty B, Yu A, Elsheikh A. Evaluation of the relationship of corneal biomechanical metrics with physical intraocular pressure and central corneal thickness in ex vivo rabbit eye globes. Exp Eye Res 2015; 137:11-7. [PMID: 26026878 DOI: 10.1016/j.exer.2015.05.018] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Revised: 05/14/2015] [Accepted: 05/26/2015] [Indexed: 10/23/2022]
Abstract
The relationship of corneal biomechanical metrics provided by the Ocular Response Analyzer (ORA) and Corvis ST (CVS) with physical intraocular pressure (IOPp) and central corneal thickness (CCT) was evaluated. Thirty fresh enucleated eyes of 30 rabbits were used in ex vivo whole globe inflation experiments. IOPp was measured with a pressure transducer and increased from 7.5 to 37.5 mmHg in steps of 7.5 mmHg while biomechanical data was acquired using the ORA and CVS. At least 3 examinations were performed at each pressure level, where CCT and twelve biomechanical metrics were recorded and analyzed as a function of IOPp. The biomechanical metrics included corneal hysteresis (CH) and corneal resistance factor (CRF), obtained by the ORA. They also included the applanation times (A1T, A2T), lengths (A1L, A2L) and velocities (A1V, A2V), in addition to the highest concavity time (HCT), peak distance (PD), radius (HR) and deformation amplitude (DA), obtained by the CVS. The variation of CCT and the twelve biomechanical metrics for the 30 rabbit eyes tested across the 5 pressure stages considered (inter-pressure differences) were statistically significant (P = 0.00). IOPp was highly to moderately correlated with most biomechanical metrics, especially CRF, A1T, A1V, A2V, PD and DA, while the relationships with CH, A2T, A1L and HCT were poor. IOP has important influences on most corneal biomechanical metrics provided by CVS and ORA. Two biomechanical metrics A1V and HR were influenced by CCT after correcting for the effect of IOP in most pressure stages, while the correlation with others were weak. Comparisons of research groups based on ORA and CVS with different IOPs and CCTs may lead to possible misinterpretations if both or one of which are not considered in the analysis.
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Affiliation(s)
- FangJun Bao
- The Affiliated Eye Hospital of WenZhou Medical University, Wenzhou, 325027, China; The Institution of Ocular Biomechanics, Wenzhou Medical University, Wenzhou, Zhejiang Province, 325027, China
| | - ManLi Deng
- The Affiliated Eye Hospital of WenZhou Medical University, Wenzhou, 325027, China; The Institution of Ocular Biomechanics, Wenzhou Medical University, Wenzhou, Zhejiang Province, 325027, China
| | - QinMei Wang
- The Affiliated Eye Hospital of WenZhou Medical University, Wenzhou, 325027, China; The Institution of Ocular Biomechanics, Wenzhou Medical University, Wenzhou, Zhejiang Province, 325027, China
| | - JinHai Huang
- The Affiliated Eye Hospital of WenZhou Medical University, Wenzhou, 325027, China; The Institution of Ocular Biomechanics, Wenzhou Medical University, Wenzhou, Zhejiang Province, 325027, China
| | - Jing Yang
- The Affiliated Eye Hospital of WenZhou Medical University, Wenzhou, 325027, China; The Institution of Ocular Biomechanics, Wenzhou Medical University, Wenzhou, Zhejiang Province, 325027, China
| | - Charles Whitford
- School of Engineering, University of Liverpool, Liverpool, L69 3GH, UK
| | - Brendan Geraghty
- School of Engineering, University of Liverpool, Liverpool, L69 3GH, UK
| | - Ayong Yu
- The Affiliated Eye Hospital of WenZhou Medical University, Wenzhou, 325027, China; The Institution of Ocular Biomechanics, Wenzhou Medical University, Wenzhou, Zhejiang Province, 325027, China.
| | - Ahmed Elsheikh
- School of Engineering, University of Liverpool, Liverpool, L69 3GH, UK; National Institute for Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, UK
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Abstract
PURPOSE OF REVIEW Glaucoma is a leading cause of irreversible blindness worldwide. It is estimated that roughly 60.5 million people had glaucoma in 2010 and that this number is increasing. Many patients continue to lose vision despite apparent disease control according to traditional risk factors. The purpose of this review is to discuss the recent findings with regard to corneal hysteresis, a variable that is thought to be associated with the risk and progression of glaucoma. RECENT FINDINGS Low corneal hysteresis is associated with optic nerve and visual field damage in glaucoma and the risk of structural and functional glaucoma progression. In addition, hysteresis may enhance intraocular pressure (IOP) interpretation: low corneal hysteresis is associated with a larger magnitude of IOP reduction following various glaucoma therapies. Corneal hysteresis is dynamic and may increase in eyes after IOP-lowering interventions are implemented. SUMMARY It is widely accepted that central corneal thickness is a predictive factor for the risk of glaucoma progression. Recent evidence shows that corneal hysteresis also provides valuable information for several aspects of glaucoma management. In fact, corneal hysteresis may be more strongly associated with glaucoma presence, risk of progression, and effectiveness of glaucoma treatments than central corneal thickness.
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Shen Y, Chen Z, Knorz MC, Li M, Zhao J, Zhou X. Comparison of Corneal Deformation Parameters After SMILE, LASEK, and Femtosecond Laser-Assisted LASIK. J Refract Surg 2014; 30:310-8. [DOI: 10.3928/1081597x-20140422-01] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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