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Accuracy and reliability of measurements obtained with a noncontact tono-pachymeter for clinical use in mass screening. Sci Rep 2021; 11:8900. [PMID: 33903678 PMCID: PMC8076298 DOI: 10.1038/s41598-021-88364-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 04/12/2021] [Indexed: 11/09/2022] Open
Abstract
We evaluated the reliability and accuracy of the noncontact CT-1P tonopachymeter (Topcon, Japan) in terms of intraocular pressure (IOP) and central corneal thickness (CCT). One hundred sixty-three healthy participants and 33 patients with open angle glaucoma were enrolled. IOPs were measured by CT-1P (T-IOP) and Goldmann applanation tonometer (G-IOP), and CCTs were measured by the CT-1P (T-CCT) and an ultrasound pachymeter (US-CCT). Both CCT instrument-adjusted (T-IOP-C) and unadjusted T-IOPs (T-IOP-NC) were included. Pearson correlation coefficients and biases assessed with Bland-Altman analysis with 95% confidence interval (CI) were calculated for reliability evaluation. Intrasession repeatability was excellent for both T-IOP (intraclass correlation coefficient [ICC] 0.91) and T-CCT (ICC 0.98). Intersession reproducibility was also excellent for T-CCT (ICC 0.94). T-IOP-NC and T-IOP-C both showed significant correlations with G-IOP (r = 0.801, P < 0.001 and r = 0.658, P < 0.001, respectively). T-CCT was also strongly correlated with US-CCT (r = 0.958; P < 0.001). T-IOP-NC and T-IOP-C both showed a positive bias (1.37 mmHg, 95% CI [1.14, 1.61] and 2.77 mmHg, 95% CI [2.49, 3.05], respectively). T-CCT showed a negative bias of - 17.3 µm (95% CI [-18.8, - 15.8]). With cautious interpretation, the CT-1P may offer good feasibility for IOP and CCT measurement in screening centers.
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Doughty MJ. Non-contact specular microscopy with Topcon instruments to assess central corneal thickness of healthy human eyes - A 20 year review. Cont Lens Anterior Eye 2020; 44:101385. [PMID: 33341365 DOI: 10.1016/j.clae.2020.11.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 10/06/2020] [Accepted: 11/12/2020] [Indexed: 11/18/2022]
Abstract
BACKGROUND The purpose of this review was to evaluate the consistency of central corneal thickness (CCT) values reported with use of Topcon SP-2000 P and SP-3000 P non-contact specular microscopes since their introduction in 1999 with the two microscopes having been commonly used in a wide range of studies. METHODS As a primary resource, PubMed was used to search for peer-reviewed articles in any language that included CCT values obtained with non-contact specular microscopy reported for humans with nominally healthy corneas. Relevant articles were obtained and any cited publications also checked. RESULTS A total of 76 articles were identified which reported CCT on different small-to-moderate sized groups of individuals, published between 1999 and 2019. From these, an overall group mean CCT value of 0.525 ± 0.013 mm (median 0.525 mm) can be calculated. An estimated 95 % confidence interval (CI, based on 1.96 SD) would be between 0.500 and 0.550 mm. For the two Topcon models, the group mean ± SD values were 0.529 ± 0.013 mm and 0.517 ± 010 mm respectively. An assessment of the CCT data sets in relation to the reported average age indicated no statistically significant effect (p = 0.289, r = -0.129). Very similar average CCT values were also encountered in 4 other reports where these microscopes were used in large-scale population studies as well as in 2 other reports using the newer Topcon SP-1 P model. CONCLUSIONS The Topcon stand-alone non-contact specular microscopes have yielded consistent and predictable corneal thickness measures over many years.
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Affiliation(s)
- M J Doughty
- Glasgow-Caledonian University, Dept Vis Sci, Glasgow, G4 OBA, United Kingdom
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Li M, Yang D, Zhao Y, Yang W, Shang J, Zhou X, Yao P, Yang D, Lin X, Zhou X. Impact of ablation ratio on 5-year postoperative posterior corneal stability after refractive surgery: SMILE and FS-LASIK. EYE AND VISION 2020; 7:53. [PMID: 33292814 PMCID: PMC7654178 DOI: 10.1186/s40662-020-00218-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Accepted: 10/20/2020] [Indexed: 11/10/2022]
Abstract
BACKGROUND To investigate the impact of the ablation ratio on 5-year postoperative posterior corneal stability in myopic eyes after small incision lenticule extraction (SMILE) and femtosecond laser-assisted in situ keratomileusis (FS-LASIK) surgery. METHODS A prospective, nonrandomized, cohort study: 80 eyes of 43 patients underwent SMILE surgery and 63 eyes of 32 patients underwent FS-LASIK surgery at the EYE & ENT Hospital, Fudan University. Ablation ratio was defined as lenticule thickness (SMILE cases) or ablation depth (FS-LASIK cases) divided by central corneal thickness (CCT). Posterior corneal elevation changes were recorded as posterior central elevation (PCE), posterior corneal surface at thinnest point (PTE) and posterior corneal mean elevation (PME). Patients were followed up at 6-month and 5-year interval to investigate the impact of the ablation ratio on posterior corneal elevation after SMILE and FS-LASIK surgery. RESULTS PCE dropped at the 6-month follow-up for both SMILE (decreased by -1.11 ± 2.93 μm, P < 0.05) and FS-LASIK groups (decreased by -0.46 ± 3.72 μm, P < 0.05). PTE also dropped in SMILE (reduced by -2.04 ± 3.02 μm, P < 0.05) and FS-LASIK group (reduced by -1.28 ± 4.21 μm, P < 0.05) at the 6-month follow-up. Stable PCE (elevation change: SMILE -0.28 ± 4.03 μm; FS-LASIK 0.79 ± 4.13 μm, P > 0.05) and PTE (elevation change: SMILE -0.08 ± 4.28 μm; FS-LASIK 1.42 ± 3.85 μm, P > 0.05) for both groups were recorded at the 5-year follow-up compared to the 6-month visit. Ablation ratio was strongly correlated with 5-year postoperative PCE (β = 2.68 ± 1.05, P < 0.01) and PTE (β = 2.35 ± 1.17, P < 0.05). Cut-off value for 5-year postoperative raised PCE and PTE was 27.3 and 27.1%, respectively. CONCLUSIONS Ablation ratio was strongly correlated with postoperative posterior corneal elevation in a 5-year follow-up in both SMILE and FS-LASIK groups. PCE and PTE underwent slight backward displacement 6-month postoperatively and remain stable at the 5-year follow-up. Threshold of the ablation ratio for resisting forward displacement of posterior corneal surface was 27.3 and 27.1% for SMILE and FS-LASIK groups, respectively.
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Affiliation(s)
- Meiyan Li
- Department of Ophthalmology, EYE & ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Shanghai, China.,Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
| | - Danjuan Yang
- Department of Ophthalmology, EYE & ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Shanghai, China.,Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
| | - Yu Zhao
- Department of Ophthalmology, EYE & ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Shanghai, China.,Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
| | - Weiming Yang
- Department of Ophthalmology and Optometry, Children's Hospital of Fudan University, Shanghai, China
| | - Jianmin Shang
- Department of Ophthalmology, EYE & ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Shanghai, China.,Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
| | - Xueyi Zhou
- Department of Ophthalmology, EYE & ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Shanghai, China.,Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
| | - Peijun Yao
- Department of Ophthalmology, EYE & ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Shanghai, China.,Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
| | - Dong Yang
- Department of Ophthalmology, EYE & ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Shanghai, China.,Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
| | - Xue Lin
- Department of Ophthalmology, Dalian Municipal Women and Children's Medical Center, Dalian, China.
| | - Xingtao Zhou
- Department of Ophthalmology, EYE & ENT Hospital, Fudan University, Shanghai, China. .,NHC Key Laboratory of Myopia (Fudan University), Shanghai, China. .,Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China. .,Department of Ophthalmology and Optometry, Children's Hospital of Fudan University, Shanghai, China.
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Canan H, Sahinoglu-Keskek N, Altan-Yaycioglu R. The relationship of central corneal thickness with the status of diabetic retinopathy. BMC Ophthalmol 2020; 20:220. [PMID: 32513125 PMCID: PMC7278140 DOI: 10.1186/s12886-020-01411-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 03/30/2020] [Indexed: 12/03/2022] Open
Abstract
Background To compare central corneal thickness (CCT) values measured by three different devices: slit-scanning topography (SST), ultrasonic pachymetry (UP), and optical coherence tomography (OCT) in diabetic eyes and compare the CCT values in patients with and without diabetic retinopathy. Methods Ninety-six patients with diabetes mellitus were included in this prospective study and divided into two groups according to the presence of diabetic retinopathy, as Group I with retinopathy and Group II without. The CCT of 96 eyes was measured by three different devices; SST (Orbscan II), UP and OCT. The results of CCT measurements with three different devices were compared. Also, the intergroup differences in CCT measurements were evaluated. Results The CCT was statistically insignificantly different between the two groups. Although the three methods of CCT measurements correlated well with each other, SST showed significantly (p < 0,0001) higher CCT results compared to both UP and OCT. Conclusions According to our results, neither the duration of DM nor the presence of diabetic retinopathy did have a significant effect on the CCT. The CCT values obtained with three devices were all in correlation. However, the results of SST were significantly higher compared to the other two. Our findings emphasize the value anterior segment OCT in CCT measurements, since it is a non-contact method and correlate very well with UP.
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Affiliation(s)
- Handan Canan
- Department of Ophthalmology, Baskent University, School of Medicine, Dadaloğlu Mah, Serinevler, 01250, Adana, Turkey.
| | - Nedime Sahinoglu-Keskek
- Department of Ophthalmology, Baskent University, School of Medicine, Dadaloğlu Mah, Serinevler, 01250, Adana, Turkey
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Hashemi H, Nabovati P, Khabazkhoob M, Emamian MH, Yekta A, Fotouhi A. Agreement of Central Corneal Thickness Measurements between Scheimpflug Photography and Optical Low-Coherence Reflectometry in Children. Semin Ophthalmol 2020; 35:252-256. [PMID: 32845784 DOI: 10.1080/08820538.2020.1810288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
PURPOSE Central corneal thickness (CCT) is a key indicator of the corneal health status and is therefore of clinical importance. The aim of the present study was to determine the agreement between Scheimpflug photography (SP) and optical low-coherence reflectometry (OLCR) systems in measuring the CCT in children. METHODS In this cross-sectional study, the samples were selected from Shahroud schoolchildren using cluster sampling. The samples then underwent optometric examinations, including the measurement of visual acuity and refraction. CCT measurements were done by the SP and OLCR systems between 8 am and 4 pm. To evaluate the agreement between these devices, 95% limits of agreement (LoA) and interclass correlation coefficient (ICC) were reported. RESULTS After applying the exclusion criteria, 4890 right eyes (53.2% male) were analyzed. The mean age of the students was 9.22 ± 1.72 years (range: 6-12 years). The mean CCT by the SP and OLCR systems was 555.30 ± 34.15 and 550.23 ± 35.11 µm, respectively. The 95% LoA between the two devices was -19.81 to 9.66 µm, and the ICC was 0.983. The CCT difference between the SP and OLCR systems was 5.61 µm in boys and 3.36 µm in girls. The CCT difference between the two devices was 6.41 µm in 6-year-old and 3.54 µm in 12-year-old children. The 95% LoA was -17.96 to 9.58 µm and -18.89 to 8.47 µm and the ICC was 0.987 and 0.984 in myopic and hyperopic subjects, respectively. CONCLUSION The results of this study showed a high agreement between OLCR and SP measurements of CCT in children.
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Affiliation(s)
- Hassan Hashemi
- Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital , Tehran, Iran
| | - Payam Nabovati
- Rehabilitation Research Center, Department of Optometry, School of Rehabilitation Sciences, Iran University of Medical Sciences , Tehran, Iran
| | - Mehdi Khabazkhoob
- Department of Medical Surgical Nursing, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences , Tehran, Iran
| | - Mohammad Hassan Emamian
- Ophthalmic Epidemiology Research Center, Shahroud University of Medical Sciences , Shahroud, Iran
| | - Abbasali Yekta
- Refractive Errors Research Center, 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
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De Bernardo M, Cornetta P, Marotta G, Salerno G, De Pascale I, Rosa N. Measurement of corneal thickness using Pentacam HR versus Nidek CEM-530 specular microscopy. J Int Med Res 2019; 48:300060519892385. [PMID: 31878803 PMCID: PMC7783267 DOI: 10.1177/0300060519892385] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Objective To compare corneal thickness (CT) measurements using the CEM-530 (Nidal,
Gamagori, Japan) and Pentacam HR (Oculus, Wetzlar, Germany). Methods The CT of 209 healthy subjects (209 right eyes) aged 24 to 89 years
(71.35 ± 10.72 years) was measured at the corneal apex (CA), pupil center
(PC), and thinnest point (TP) with the Pentacam HR and at the corneal center
with the CEM-530 in random order at the same time of day. Results A good correlation but statistically significant difference was found between
the CEM-530 and Pentacam HR measurements at the CA (6.10 ± 8.12 µm,
R2 = 0.8947), PC (7.46 ± 8.57 µm, R2 = 0.8826),
and TP (12.44 ± 10.04 µm, R2 = 0.8392). Comparison of the two
devices produced the following regression formulas: y = 0.8859x + 57.644 for
the CA, y = 0.8852x +56.657 for the PC, and y = 0.8557x + 68.148 for the TP,
where x is the CT obtained with the CEM-530 and y is that obtained with the
Pentacam HR. Conclusions These findings indicate that the CEM-530 produces a thicker corneal
measurement than the Pentacam HR. The herein-proposed correcting factors are
needed to reliably compare these devices.
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Affiliation(s)
- Maddalena De Bernardo
- Department of Medicine, Surgery, and Dentistry, Scuola Medica Salernitana, University of Salerno, Baronissi, Salerno, Italy
| | - Palmiro Cornetta
- Department of Medicine, Surgery, and Dentistry, Scuola Medica Salernitana, University of Salerno, Baronissi, Salerno, Italy
| | - Giuseppe Marotta
- Department of Medicine, Surgery, and Dentistry, Scuola Medica Salernitana, University of Salerno, Baronissi, Salerno, Italy
| | - Giulio Salerno
- Department of Medicine, Surgery, and Dentistry, Scuola Medica Salernitana, University of Salerno, Baronissi, Salerno, Italy
| | - Ilaria De Pascale
- Department of Medicine, Surgery, and Dentistry, Scuola Medica Salernitana, University of Salerno, Baronissi, Salerno, Italy
| | - Nicola Rosa
- Department of Medicine, Surgery, and Dentistry, Scuola Medica Salernitana, University of Salerno, Baronissi, Salerno, Italy
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Mayali H, Altinisik M, Sencan S, Pirildar T, Kurt E. A multimodal ophthalmic analysis in patients with systemic sclerosis using ocular response analyzer, corneal topography and specular microscopy. Int Ophthalmol 2019; 40:287-296. [PMID: 31564047 DOI: 10.1007/s10792-019-01173-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2019] [Accepted: 09/19/2019] [Indexed: 11/30/2022]
Abstract
PURPOSE To conduct a multimodal ophthalmic evaluation of systemic sclerosis (SSc) in patients using ocular response analyzer (ORA), Pentacam, and specular microscopy (SM). METHODS Thirty-one SSc patients and a group of age- and sex-matched controls were enrolled in this cross-sectional study. Corneal hysteresis (CH), corneal resistance factor (CRF), corneal-compensated intraocular pressure (IOPcc), and Goldmann-correlated IOP (IOPg) were measured with ORA. Anterior chamber depth (ACD), central corneal thickness (CCT), and corneal volume (CV) measurements were obtained using Pentacam. Corneal endothelial cell density (ECD) and CCT were evaluated by SM. RESULTS SSc patients had significantly lower CH, ACD, and ECD values compared to the control group (p = 0.018; < 0.001; < 0.001, respectively). There was no significant difference regarding CRF, IOP, CV, or CCT measurements acquired by Pentacam and SM. Regarding CCT, SM and Pentacam showed relatively better agreement in SSc patients. CONCLUSIONS Multimodal imaging can provide more comprehensive and useful information regarding the ocular involvement of systemic diseases. The multimodal evaluation in our study demonstrated that the pathologic effects of SSc may manifest as reductions in ACD, corneal elasticity, and ECD before there are any detectable changes in corneal thickness or IOP.
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Affiliation(s)
- Huseyin Mayali
- Ophthalmology Department, Medical School, Manisa Celal Bayar University, Manisa, Turkey
| | - Muhammed Altinisik
- Ophthalmology Department, Medical School, Manisa Celal Bayar University, Manisa, Turkey.
| | - Secil Sencan
- Ophthalmology Department, Tinaztepe Hospital, Izmir, Turkey
| | - Timur Pirildar
- Ophthalmology Department, Medical School, Manisa Celal Bayar University, Manisa, Turkey
| | - Emin Kurt
- Ophthalmology Department, Medical School, Manisa Celal Bayar University, Manisa, Turkey
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Ohn K, Lee MY, Lee YC, Shin HY. Comparison of Central Corneal Thickness Measurements between Noncontact Specular Microscopy and Ultrasound Pachymetry. JOURNAL OF THE KOREAN OPHTHALMOLOGICAL SOCIETY 2019. [DOI: 10.3341/jkos.2019.60.7.635] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Kyoung Ohn
- Department of Ophthalmology, Uijeongbu St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Uijeongbu, Korea
| | - Mee Yon Lee
- Department of Ophthalmology, Uijeongbu St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Uijeongbu, Korea
| | - Young Chun Lee
- Department of Ophthalmology, Uijeongbu St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Uijeongbu, Korea
| | - Hye Young Shin
- Department of Ophthalmology, Uijeongbu St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Uijeongbu, Korea
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González-Pérez J, Queiruga Piñeiro J, Sánchez García Á, González Méijome JM. Comparison of Central Corneal Thickness Measured by Standard Ultrasound Pachymetry, Corneal Topography, Tono-Pachymetry and Anterior Segment Optical Coherence Tomography. Curr Eye Res 2018; 43:866-872. [PMID: 29634372 DOI: 10.1080/02713683.2018.1461910] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
PURPOSE To compare central corneal thickness (CCT) measured by standard ultrasound pachymetry (USP), and three non-contact devices in healthy eyes. METHODS A cross-sectional study of CCT measurement in 52 eyes of 52 healthy volunteers was done by a single examiner at Ocular Surface and Contact Lens Laboratory. Three consecutive measurements were done by standard USP, non-contact tono-pachymeter, Pentacam corneal topographer, and Anterior Segment Optical Coherence Tomography (AS-OCT). The mean values were used for assessment. The results were compared using multivariate ANOVA, linear regression, and Pearson correlation. Agreement among the devices was analyzed using mean differences and Bland-Altman analysis with 95% limits of agreement (LoA). Finally, reliability was analyzed using intraclass correlation coefficient (ICC). RESULTS Mean CCT by ultrasound pachymeter, tono-pachymeter, corneal topographer and AS-OCT were 558.9 ± 31.2 µm, 525.8 ± 43.1 µm, 550.4 ± 30.5 µm, and 545.9 ± 30.5 µm respectively. There was a significant positive correlation between AS-OCT and USP (Pearson correlation = 0.957, p < 0.001), corneal topography and USP (Pearson correlation = 0.965, p < 0.001), and corneal topography and AS-OCT (Pearson correlation = 0.965, p < 0.001). There was a lower correlation between CT-1P tono-pachymeter and the other three modalities. Intraclass correlation coefficients show an excellent reliability between pairs except for CT-1P against the other three instruments that were found moderate. CONCLUSIONS CT-1P tono-pachymeter underestimates CCT measurements compared to Scheimpflug system, AS-OCT device, and USP. Mean CCT among USP, Pentacam and AS-OCT were comparable and had significant linear correlations. In clinical practice, these three modalities could be interchangeable in healthy patients.
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Affiliation(s)
- Javier González-Pérez
- a Ocular Surface and Contact Lens Research Laboratory, Faculty of Optometry , University of Santiago de Compostela , Santiago de Compostela , Spain
| | | | - Ángelx Sánchez García
- a Ocular Surface and Contact Lens Research Laboratory, Faculty of Optometry , University of Santiago de Compostela , Santiago de Compostela , Spain
| | - José Manuel González Méijome
- a Ocular Surface and Contact Lens Research Laboratory, Faculty of Optometry , University of Santiago de Compostela , Santiago de Compostela , Spain.,c Clinical & Experimental Optometry Research Lab, Center of Physics (Optometry) - School of Sciences , University of Minho , Gualtar - Braga , Portugal
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Corneal Thickness Response after Anesthetic Eye Drops: Our Own Results and Meta-Analysis. BIOMED RESEARCH INTERNATIONAL 2018; 2018:4743721. [PMID: 29693008 PMCID: PMC5859836 DOI: 10.1155/2018/4743721] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 01/29/2018] [Indexed: 01/11/2023]
Abstract
We aimed to test if there are different patterns in the central corneal thickness (CCT) response after instilling oxybuprocaine anesthetic eye drops and also to determine whether there is a significant change in the CCT. CCT was measured in 60 eyes of 60 healthy subjects before and during the hour after oxybuprocaine 0.4% eye drops were instilled. In addition, a systematic review and meta-analysis were carried out in order to answer the following PICO (patient, intervention, comparison, and outcome) question: What effect do anesthetic eye drops have on CCT values? We found no significant changes in the mean CCT values during the hour's observation (ANOVA, p = 0.209), and the meta-analysis revealed no statistically significant changes in the CCT after anesthesia (Q-Value = 1.111; p value = 1.000; I2 = 0.000; Tau2 = 0.000; Stderr = 0.020). However, we found three CCT response patterns 5 minutes after anesthesia: Pattern 1, subjects with no significant changes in their CCT values (n = 14, 46.7%); Pattern 2, subjects with significant CCT increases (n = 11, 36.7%); and Pattern 3, subjects with significant CCT decreases (n = 5, 16.7%). In sum, there are no significant changes in the CCT after anesthesia, but there are three different CCT response patterns 5 minutes after anesthesia.
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Martin R. Cornea and anterior eye assessment with placido-disc keratoscopy, slit scanning evaluation topography and scheimpflug imaging tomography. Indian J Ophthalmol 2018; 66:360-366. [PMID: 29480244 PMCID: PMC5859588 DOI: 10.4103/ijo.ijo_850_17] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 09/28/2017] [Indexed: 12/11/2022] Open
Abstract
Current corneal assessment technologies make the process of corneal evaluation extremely fast and simple and several devices and technologies allow to explore and to manage patients. The purpose of this special issue is to present and also to update in the evaluation of cornea and ocular surface and this second part, reviews a description of the corneal topography and tomography techniques, providing updated information of the clinical recommendations of these techniques in eye care practice. Placido-based topographers started an exciting anterior corneal surface analysis that allows the development of current corneal tomographers that provide a full three-dimensional reconstruction of the cornea including elevation, curvature, and pachymetry data of anterior and posterior corneal surfaces. Although, there is not an accepted reference standard technology for corneal topography description and it is not possible to determine which device produces the most accurate topographic measurements, placido-based topographers are a valuable technology to be used in primary eye care and corneal tomograhers expanding the possibilities to explore cornea and anterior eye facilitating diagnosis and follow-up in several situations, raising patient follow-up, and improving the knowledge regarding to the corneal anatomy. Main disadvantages of placido-based topographers include the absence of information about the posterior corneal surface and limited corneal surface coverage without data from the para-central and/or peripheral corneal surface. However, corneal tomographers show repeatable anterior and posterior corneal surfaces measurements, providing full corneal thickness data improving cornea, and anterior surface assessment. However, differences between devices suggest that they are not interchangeable in clinical practice.
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Affiliation(s)
- Raul Martin
- Departamento de Física Teórica, Atómica y Óptica, Universidad de Valladolid, Valladolid, Spain
- Instituto Universitario de Oftalmobiología Aplicada (IOBA), Universidad de Valladolid, Valladolid, Spain
- IOBA Eye Institute, School of Optometry, University of Valladolid, Valladolid, Spain
- Faculty of Health and Human Sciences, Plymouth University, PL6 8BH Plymouth, United Kingdom
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12
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Shetty R, Agrawal A, Deshmukh R, Kaweri L, Rao HL, Nagaraja H, Jayadev C. Effect of post crosslinking haze on the repeatability of Scheimpflug-based and slit-scanning imaging devices. Indian J Ophthalmol 2017; 65:305-310. [PMID: 28513495 PMCID: PMC5452583 DOI: 10.4103/ijo.ijo_690_16] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Purpose: The aim of this study was to analyze the effect of postcollagen crosslinking (CXL) haze on the measurement and repeatability of pachymetry and mean keratometry (Km) of four corneal topographers. Materials and Methods: Sixty eyes of sixty patients with progressive keratoconus who had undergone accelerated CXL (ACXL) underwent imaging with a scanning slit imaging device (Orbscan II) and three Scheimpflug imaging devices (Pentacam HR, Sirius, and Galilei). Post-ACXL haze was measured using the densitometry software on the Pentacam HR. Readings of the thinnest corneal thickness (TCT) and Km from three scans of each device were analyzed. Effect of haze on the repeatability of TCT and Km measurements was evaluated using regression models. Repeatability was assessed by coefficient of variation. Results: Corneal densitometry in different zones affected the repeatability of TCT measurement of Orbscan (P < 0.05) significantly but not the repeatability of TCT with Pentacam HR and Sirius (P = 0.03 and 0.05, respectively). Km values were affected by haze when measured with the Pentacam HR (P < 0.05). The repeatability of Km readings for all devices was unaffected by haze. In the anterior 0–2 mm and 2–6 mm zone, TCT (P = 0.43 and 0.45, respectively), Km values (P = 0.4 and 0.6, respectively), repeatability of TCT (P = 0.1 in both zones), and Km (P = 0.5 and 0.1, respectively) with Galilei were found to be the most reliable. Conclusion: Galilei measurements appear to be least affected by post-ACXL haze when compared with other devices. Hence, topography measurements in the presence of haze need to be interpreted with caution.
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Affiliation(s)
- Rohit Shetty
- Department of Cornea and Refractive Surgery, Narayana Nethralaya Eye Hospital, Bengaluru, Karnataka, India
| | - Aarti Agrawal
- Department of Cornea and Refractive Surgery, Narayana Nethralaya Eye Hospital, Bengaluru, Karnataka, India
| | - Rashmi Deshmukh
- Department of Cornea and Refractive Surgery, Narayana Nethralaya Eye Hospital, Bengaluru, Karnataka, India
| | - Luci Kaweri
- Department of Cornea and Refractive Surgery, Narayana Nethralaya Eye Hospital, Bengaluru, Karnataka, India
| | - Harsha L Rao
- Department of Cornea and Refractive Surgery, Narayana Nethralaya Eye Hospital, Bengaluru, Karnataka, India
| | - Harsha Nagaraja
- Department of Cornea and Refractive Surgery, Narayana Nethralaya Eye Hospital, Bengaluru, Karnataka, India
| | - Chaitra Jayadev
- Department of Cornea and Refractive Surgery, Narayana Nethralaya Eye Hospital, Bengaluru, Karnataka, India
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Repeatability of Central Corneal Thickness Measurement Using Rotating Scheimpflug Camera in Dry and Normal Eyes. Eye Contact Lens 2017; 44 Suppl 2:S29-S32. [PMID: 28244934 DOI: 10.1097/icl.0000000000000373] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To compare the repeatability of central corneal thickness (CCT) measurement using the Pentacam between dry eyes and healthy eyes, as well as to investigate the effect of artificial tears on CCT measurement. METHODS The corneal thicknesses of 34 patients with dry eye and 28 healthy subjects were measured using the Pentacam. One eye from each subject was assigned randomly to a repeatability test, wherein a single operator performed three successive CCT measurements time points-before and 5 min after instillation of one artificial teardrop. The repeatability of measurements was assessed using the coefficient of repeatability and the intraclass correlation coefficient. RESULTS The coefficient of repeatability values of the CCT measurements in dry and healthy eyes were 24.36 and 10.69 μm before instillation, and 16.85 and 9.72 μm after instillation, respectively. The intraclass correlation coefficient was higher in healthy eyes than that of in dry eyes (0.987 vs. 0.891), and it had improved significantly in dry eyes (0.948) after instillation of one artificial teardrop. The CCT measurement fluctuated in dry eyes (repeated-measures analysis of variance, P<0.001), whereas no significant changes were detected in healthy eyes, either before or after artificial tear instillation. CONCLUSIONS Central corneal thickness measurement is less repeatable in dry eyes than in healthy eyes. Artificial tears improve the repeatability of CCT measurements obtained using the Pentacam in dry eyes.
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Altay Y, Balta O, Demirok G, Burcu A, Balta OB, Ornek F. Agreement between Corneal Thickness Measurements Using Pentacam Scheimpflug Camera, Noncontact Specular Microscopy, and Ultrasonographic Pachymetry in Diabetic Patients. Curr Eye Res 2016; 42:187-194. [PMID: 27348734 DOI: 10.3109/02713683.2016.1170854] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE To evaluate the agreement of corneal thickness (CT) measurements obtained by the Pentacam Scheimpflug camera, noncontact specular microscopy (SM), and ultrasonographic pachymetry (UP) in diabetic (DM) patients; and whether duration of diabetes and level of Hb A1c affect the agreement. MATERIALS AND METHODS The CT was measured in 127 patients with DM, and 137 age and sex-matched healthy controls sequentially by Pentacam, SM, and UP. Also diabetic subjects were subdivided according to duration of diabetes and Hb A1c levels. Pearson correlation analysis, linear regression analysis, and Bland-Altman plots were used for examination of agreement. RESULTS We found an excellent and statistically significant correlation of CT measurements between Pentacam-SM (R2 = 0.768; R2 = 0.855), Pentacam-UP (R2 = 0.546; R2 = 0.652), and SM-UP (R2 = 0.759; R2 = 0.797) in diabetic and control groups, respectively. We performed further comparisons of the pair of instruments using the Bland-Altman analysis, and the mean difference between pair of methods was much smaller for SM-UP pair (-4.20 ± 9.79 in diabetic, and -4.58 ± 8.08 in control group). The group having Hb A1c level less than 7.5% showed the best agreement between SM-UP pair as in the control group. Whereas Pentacam-UP showed the best agreement in the group having Hb A1c level ≥7.5%. The best agreement was between Pentacam-UP in 0-4 year group, and between Pentacam-SM in 5-9 year and ≥10 year groups. CONCLUSION SM-UP pair showed a higher agreement in diabetic patients. According to subgroup analyses, Hb A1c level, rather than the duration of diabetes, may determine the agreement of these pachymetry devices. But the difference in CT measurements between devices can still influence clinical diagnosis and treatment. Therefore, these methods are not completely interchangeable.
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Affiliation(s)
- Yeşim Altay
- a Department of Ophthalmology , Ophthalmologist, Ankara Training and Research Hospital , Ankara , Turkey
| | - Ozgur Balta
- a Department of Ophthalmology , Ophthalmologist, Ankara Training and Research Hospital , Ankara , Turkey
| | - Gülizar Demirok
- b Department of Ophthalmology , Ufuk University Faculty of Medicine , Ankara , Turkey
| | - Ayse Burcu
- a Department of Ophthalmology , Ophthalmologist, Ankara Training and Research Hospital , Ankara , Turkey
| | - Oyku Bezen Balta
- c Department of Family Medicine , Yildirim Beyazit University Faculty of Medicine , Ankara , Turkey
| | - Firdevs Ornek
- a Department of Ophthalmology , Ophthalmologist, Ankara Training and Research Hospital , Ankara , Turkey
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Measurements of central corneal thickness and endothelial parameters with three different non-contact specular microscopy devices. Int Ophthalmol 2016; 37:229-233. [PMID: 27221264 DOI: 10.1007/s10792-016-0264-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 05/13/2016] [Indexed: 10/21/2022]
Abstract
We aimed to compare the measurements of central corneal thickness (CCT) and endothelial parameters with three different non-contact specular microscopy (SM) devices. Fifteen eyes of 15 healthy individuals (6 males; 9 females) were enrolled in the study. Mean age was 37.93 ± 15.13 years. Endothelial parameters and CCT were measured with Nidek CEM-530, Topcon SP-3000P, and Tomey EM-3000 SM devices by the same physician. Endothelial parameters included endothelial cell count (ECC), maximum, minimum, and average endothelial cell size. and hexagonality ratio. There were no statistically significant differences in ECC, CTT, and average endothelial size (AES) between the devices (p > 0.05). The measurement of maximum endothelial size (MES) was different between Nidek SM and Topcon SM devices (p = 0.001), but there was no difference in MES between Nidek SM and Tomey SM (p = 0.058), and between Topcon SM and Tomey SM (p = 0.081). There was no difference in minimum endothelial size (MinES) between Nidek SM and Topcon SM (p = 0.794); however, there was a significant difference in MinES between Tomey SM and Nidek SM (p < 0.001), and between Tomey SM and Topcon SM (p < 0.001). Comparison of hexagonality ratio showed statistically significant difference between the devices (p < 0.001). No significant differences in the measurements of ECC, CCT, and AES were detected between different SM devices, whereas a statistically significant difference in hexagonality ratio was detected between the devices. These devices should not be used alternatively in the endothelial morphology assessment in patient's follow-up.
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Evaluation of Central Corneal Thickness Using Corneal Dynamic Scheimpflug Analyzer Corvis ST and Comparison with Pentacam Rotating Scheimpflug System and Ultrasound Pachymetry in Normal Eyes. J Ophthalmol 2015; 2015:767012. [PMID: 26697213 PMCID: PMC4678087 DOI: 10.1155/2015/767012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 11/16/2015] [Indexed: 11/25/2022] Open
Abstract
Purpose. To assess the repeatability and reproducibility of central corneal thickness (CCT) measurements by corneal dynamic Scheimpflug analyzer Corvis ST in normal eyes and compare the agreement with Pentacam rotating Scheimpflug System and ultrasound pachymetry. Methods. 84 right eyes underwent Corvis ST measurements performed by two operators. The test-retest repeatability (TRT), within-subject coefficient of variation (CoV), and intraclass correlation coefficient (ICC) were used to evaluate the intraoperator repeatability and interoperator reproducibility. CCT measurements also were obtained from Pentacam and ultrasound pachymetry by the first operator. The agreement between the three devices was evaluated with 95% limits of agreement (LoA) and Bland-Altman plots. Results. Corvis ST showed high repeatability as indicated by TRT ≤ 13.0 μm, CoV < 0.9%, and ICC > 0.97. The interoperator reproducibility was also excellent. The CoV was <0.9%, and ICC was >0.97. Corvis ST showed significantly lower values than Pentacam and ultrasound pachymetry (P < 0.001). The 95% LoA between Corvis ST and Pentacam or ultrasound pachymetry were −15.8 to 9.5 μm and −27.9 to 12.3 μm, respectively. Conclusions. Corvis ST showed excellent repeatability and interoperator reproducibility of CCT measurements in normal eyes. Corvis ST is interchangeable with Pentacam but not with ultrasound pachymetry.
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Simonini I, Pandolfi A. Customized Finite Element Modelling of the Human Cornea. PLoS One 2015; 10:e0130426. [PMID: 26098104 PMCID: PMC4476710 DOI: 10.1371/journal.pone.0130426] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 05/20/2015] [Indexed: 11/25/2022] Open
Abstract
Aim To construct patient-specific solid models of human cornea from ocular topographer data, to increase the accuracy of the biomechanical and optical estimate of the changes in refractive power and stress caused by photorefractive keratectomy (PRK). Method Corneal elevation maps of five human eyes were taken with a rotating Scheimpflug camera combined with a Placido disk before and after refractive surgery. Patient-specific solid models were created and discretized in finite elements to estimate the corneal strain and stress fields in preoperative and postoperative configurations and derive the refractive parameters of the cornea. Results Patient-specific geometrical models of the cornea allow for the creation of personalized refractive maps at different levels of IOP. Thinned postoperative corneas show a higher stress gradient across the thickness and higher sensitivity of all geometrical and refractive parameters to the fluctuation of the IOP. Conclusion Patient-specific numerical models of the cornea can provide accurate quantitative information on the refractive properties of the cornea under different levels of IOP and describe the change of the stress state of the cornea due to refractive surgery (PRK). Patient-specific models can be used as indicators of feasibility before performing the surgery.
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Affiliation(s)
- Irene Simonini
- Dipartimento di Matematica, Politecnico di Milano, Milano, Italy
| | - Anna Pandolfi
- Dipartimento di Ingegneria Civile ed Ambientale, Politecnico di Milano, Milano, Italy
- * E-mail:
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Sadoughi MM, Einollahi B, Einollahi N, Rezaei J, Roshandel D, Feizi S. Measurement of Central Corneal Thickness Using Ultrasound Pachymetry and Orbscan II in Normal Eyes. J Ophthalmic Vis Res 2015; 10:4-9. [PMID: 26005545 PMCID: PMC4424717 DOI: 10.4103/2008-322x.156084] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 10/25/2014] [Indexed: 11/26/2022] Open
Abstract
Purpose: To compare ultrasound pachymetry and Orbscan II for measurement of central corneal thickness (CCT) in normal eyes. Methods: The current study was performed at Labbafinejad Medical Center (LMC), Tehran, Iran. Three hundred eyes from 150 healthy individuals referred for keratorefractive surgery were assessed first by Orbscan II and then by ultrasound pachymetry, and CCT values were recorded and compared. Results: Overall, Orbscan II overestimated CCT as compared to ultrasound pachymetry by about 2.4% (mean values 547.6 ± 34.7 versus 534.8 ± 34.7, respectively, P < 0.001). The difference was more significant when CCT was less than 500 microns (mean values 493.2 ± 16.9 versus 479.9 ± 15.6, mean overestimation: 2.6%, P < 0.001). There was good linear correlation between the two methods (Pearson's correlation r = 0.968, P < 0.0001). Conclusion: Orbscan II has good correlation with ultrasound pachymetry for measurement of CCT in normal eyes; however Orbscan II should not be used to evaluate corneal thickness before keratorefractive surgeries, as it tends to overestimate corneal thickness and may result in undesirable, low residual stromal thickness.
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Affiliation(s)
| | - Bahram Einollahi
- Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Neda Einollahi
- Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Javad Rezaei
- Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Danial Roshandel
- Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Sepehr Feizi
- Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Naderan M, Shoar S, Naderan M, Kamaleddin MA, Rajabi MT. Comparison of corneal measurements in keratoconic eyes using rotating Scheimpflug camera and scanning-slit topography. Int J Ophthalmol 2015; 8:275-80. [PMID: 25938040 DOI: 10.3980/j.issn.2222-3959.2015.02.11] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 08/25/2014] [Indexed: 11/02/2022] Open
Abstract
AIM To compare the anterior segment measurements obtained by rotating Scheimpflug camera (Pentacam) and Scanning-slit topography (Orbscan IIz) in keratoconic eyes. METHODS A total of 121 patients, 71 males (58.7%) and 50 females (41.3%) (214 eyes) with the diagnosis of keratoconus (KC) were enrolled in this study. Following diagnosis of KC by slit-lamp biomicroscopic examination, central corneal thickness (CCT), thinnest corneal thickness (TCT), anterior chamber depth (ACD), and pupil diameter (PD) were measured by a single examiner using successive instrumentation by Pentacam and Orbscan. RESULTS There was no significant difference between the two instruments for the measurement of CCT and TCT. In contrast, scanning-slit topography measured ACD (3.46±0.40 mm vs. 3.38±0.33 mm, P=0.019) and PD (4.97±1.26 mm vs 4.08±1.19 mm, P<0.001) significantly larger than rotating Scheimpflug camera. The two devices made similar measurements for CCT (95% CI: -2.94 to 5.06, P=0.602). However, the mean difference for TCT was -6.28 (95% CI: -10.51 to -2.06, P=0.004) showing a thinner measurement by Orbscan than by Pentacam. In terms of the ACD, the mean difference was 0.08 mm (95% CI: 0.04 to 0.12, P<0.001) with Orbscan giving a slightly larger value than Pentacam. Similarly, Orbscan measurement for PD was longer than Pentacam (95% CI: 0.68 to 1.08, P<0.001). CONCLUSION A good agreement was found between Pentacam and Orbscan concerning CCT measurement while comparing scanning-slit topography and rotating Scheimpflug camera there was an underestimation for TCT and overestimation for ACD and PD.
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Affiliation(s)
- Mohammad Naderan
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran 1336616351, Iran
| | - Saeed Shoar
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran 1336616351, Iran
| | - Morteza Naderan
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran 1336616351, Iran
| | | | - Mohammad Taher Rajabi
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran 1336616351, Iran
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Dependability of posterior-segment spectral domain optical coherence tomography for measuring central corneal thickness. Cornea 2015; 33:1219-24. [PMID: 25211358 DOI: 10.1097/ico.0000000000000253] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE The aim of this study was to assess the intersession and interobserver reliability of central corneal thickness (CCT) measurements using a posterior-segment spectral domain optical coherence tomography (SD-OCT). METHODS Sixty patients were examined with a posterior-segment SD-OCT system (Topcon 3D-OCT). To analyze intersession reproducibility, 1 examiner measured CCT in 60 eyes 2 times 1 week apart, and to study interobserver reproducibility, a second examiner obtained another measurement during the first session. Within-subject reproducibility, coefficient of reproducibility (CR), and intraclass correlation coefficients (ICC) were calculated. Agreement between Topcon 3D OCT and ultrasound pachymetry (USP) was also assessed. RESULTS Posterior-segment SD-OCT showed an intersession reproducibility of 12.7 μm (CR = 2.4%) and an excellent ICC (0.96). No systematic difference between sessions was found (average difference, 1.7 μm; P = 0.15). We found no significant bias between observers (mean difference, -1.5 μm; P = 0.29). The interobserver reproducibility was 16.4 μm (CR = 3.1%), and the ICC was 0.94. Topcon 3D OCT CCT values were lower than USP readings (mean difference, 7.6 ± 8.1 μm; 95% confidence interval, 9.9-5.3 μm; P < 0.001). CONCLUSIONS With a commercially available retinal SD-OCT system, reliable intersession and interobserver CCT measurements can be feasibly obtained. The criteria for a significant change, which would be the one exceeding the reproducibility, indicate that intersession and interobserver variations in CCT of more than 13 and 16 μm, respectively, may reflect true corneal change with this particular device. These estimates should help investigators and clinicians differentiate actual CCT modification from measurement random error. The slight CCT underestimation with respect to USP is within the range of other OCT devices.
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Randleman JB, Lynn MJ, Perez-Straziota CE, Weissman HM, Kim SW. Comparison of central and peripheral corneal thickness measurements with scanning-slit, Scheimpflug and Fourier-domain ocular coherence tomography. Br J Ophthalmol 2015; 99:1176-81. [PMID: 25824260 DOI: 10.1136/bjophthalmol-2014-306340] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 03/08/2015] [Indexed: 11/03/2022]
Abstract
PURPOSE To compare central, regional and relational corneal thickness values obtained with multiple technologies in normal patients and to determine their equivalence and interchangeability. METHODS Retrospective analysis of 100 eyes from 50 patients evaluated by ultrasound pachymetry (Pachette II), scanning-slit (Orbscan II), Scheimpflug (Pentacam HR) and spectral-domain ocular coherence tomography (OCT) (RTVue-100) obtained as average values (OCT-A) and point measurements (OCT-P). Measurements included central corneal thickness (CCT) for all technologies and thinnest corneal thickness for scanning-slit, Scheimpflug and OCT. Peripheral thickness measurements were obtained at the 3 mm radius in the superior (S), nasal (N), inferior (I) and temporal (T) regions. RESULTS CCT values were: 563.9±36.1μ ultrasound, 570.9±36.1μ scanning-slit, 552.8±33.8μ Scheimpflug, 550.5±32.7μ (OCT-A), 549.4±32.7μ (OCT-P). Ultrasound and scanning-slit were significantly different from each other (p<0.0001), and both were significantly different from all other devices (p<0.0001), while Scheimpflug was similar to OCT-A and OCT-P (p=0.4). Differences between CCT and thinnest corneal thickness were significantly different from all technologies except scanning-slit and OCT-A. For peripheral values, almost all locations' measurements were significantly different from one another (p<0.0001). Superior-inferior values and ratios were also significantly different from one another for almost all devices with no consistent patterns detectible. CONCLUSIONS There are significant clinically relevant differences between regional and relational thickness measurements obtained with ultrasound, scanning-slit, Scheimpflug and OCT devices. Screening metrics devised for one system do not appear directly applicable to other measurement systems.
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Affiliation(s)
- J Bradley Randleman
- Department of Ophthalmology, Emory University, Atlanta, Georgia, USA Emory Vision, Emory Eye Center, Atlanta, Georgia, USA
| | - Michael J Lynn
- Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA
| | | | | | - Sang Woo Kim
- Department of Ophthalmology, University of Ulsan College of Medicine, Ulsan, South Korea
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22
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Corneal assessment technologies: Current status. Surv Ophthalmol 2014; 59:599-614. [DOI: 10.1016/j.survophthal.2014.05.001] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Revised: 05/15/2014] [Accepted: 05/20/2014] [Indexed: 11/22/2022]
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Comparison and Evaluation of Central Corneal Thickness Using 2 New Noncontact Specular Microscopes and Conventional Pachymetry Devices. Cornea 2014; 33:576-81. [DOI: 10.1097/ico.0000000000000113] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Borrego-Sanz L, Sáenz-Francés F, Bermudez-Vallecilla M, Morales-Fernández L, Martínez-de-la-Casa J, Santos-Bueso E, Jañez L, García-Feijoo J. Agreement between Central Corneal Thickness Measured Using Pentacam, Ultrasound Pachymetry, Specular Microscopy and Optic Biometer Lenstar LS 900 and the Influence of Intraocular Pressure. Ophthalmologica 2014; 231:226-35. [DOI: 10.1159/000356724] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Accepted: 09/20/2013] [Indexed: 11/19/2022]
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Wu W, Wang Y, Xu L. Meta-analysis of Pentacam vs. ultrasound pachymetry in central corneal thickness measurement in normal, post-LASIK or PRK, and keratoconic or keratoconus-suspect eyes. Graefes Arch Clin Exp Ophthalmol 2013; 252:91-9. [PMID: 24218039 DOI: 10.1007/s00417-013-2502-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 10/08/2013] [Accepted: 10/10/2013] [Indexed: 10/26/2022] Open
Abstract
BACKGROUND The aim of this meta-analysis is to evaluate the central corneal thickness (CCT) measurement differences between Pentacam (Oculus Inc., Germany) and Ultrasound Pachymetry (USP) in normal (unoperated eyes , myopic and astigmatic eyes without corneal disease or topographic irregularity), after laser in situ keratomileusis (LASIK) or photorefractive keratectomy (PRK), and keratoconic or keratoconus suspected eyes. We assess whether Pentacam and USP have similar CCT differences in normal, thinner corneas after LASIK or PRK procedures, and kerotoconic or keratoconus suspected eyes. METHODS Data sources, including PubMed, Medline, EMBASE, and Cochrane Central Registry of Controlled Trials on the Cochrane Library, were searched to find the relevant studies. Primary outcome measures were CCT measurement between Pentacam and USP. Three groups of eyes were analyzed: normal; LASIK or PRK eyes; and keratoconus suspected or keratoconic eyes. RESULTS Nineteen studies describing 1,908 eyes were enrolled in the normal group. Pentacam results were 1.47 μm ,95 % confidence interval (CI) -2.32 to 5.27, higher than USP without statistically significant difference (P = 0.45). Nine studies with total 539 eyes were included in the corneas after LASIK or PRK. The mean difference in the CCT measurement with Pentacam and ultrasound pachymetry was 1.03 μm, with the 95 % CI -3.36 to 5.42, there was no statistically difference (P = 0.64). Four studies with a total of 185 eyes were included in the keratoconic eyes or keratoconus-suspect group, however,the mean difference was -6.33 μm (95 % CI -9.17 to-3.49), which was statistically different between Pentacam and ultrasound pachymetry in the CCT measurement (P < 0.0001). CONCLUSIONS Pentacam offers similar CCT results to ultrasound pachymetry in normal eyes, thinner corneas after LASIK or PRK procedures. However, in keratoconic or keratoconus-suspect eyes, Pentacam slightly underestimates the central corneal thickness than does ultrasound pachymetry, which may result from the difficulty in fixation of keratoconic eyes, misalignment of Pentacam and the variation of ultrasonic velocity due to the histological deformation.
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Affiliation(s)
- Wenjing Wu
- Tianjin Eye Hospital& Eye Institute, Tianjin Ophthalmology and Visual Science Key Laboratory, Clinical College of Ophthalmology, Tianjin Medical University, No 4. Gansu Rd, Heping District, Tianjin, 300020, China
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Abstract
PURPOSE The aim of this study was to compare 4 methods of central corneal thickness (CCT) measurements in terms of their agreement, repeatability, and measurement time. METHODS CCT was measured in 184 eyes of 92 healthy subjects by the same examiner. The methods used were as follows: noncontact specular microscopy (SM; Topcon SP-3000P; Topcon Corporation, Tokyo, Japan), Pentacam rotating Scheimpflug photography system (Oculus Inc, Wetzlar, Germany), optical low-coherence reflectometry (OLCR; LenStar LS900; Haag-Streit AG, Koeniz, Switzerland), and ultrasound pachymetry (UP; PachPen; Accutome Inc, Malvern, PA). The duration for each examination was measured by an independent observer. RESULTS The mean age (±SD) of the subjects was 54.3 (± 15.3) years. The mean CCTs (± SD) for SM, Pentacam, OLCR, and UP were 507.8 (± 30.2), 538.4 (± 31.7), 531.8 (± 31.4), and 528.3 (± 32.9) μm, respectively. The Bland-Altman plots showed closest agreement for OLCR-UP, followed by OLCR-Pentacam and Pentacam-UP. SM had the poorest agreement with the other methods. CCTs measured by SM were on average 20 to 30 μm thinner than those of the other methods. The coefficient of repeatability for SM, Pentacam, OLCR, and UP were 3.14%, 4.23%, 1.51%, and 3.46%, respectively. The mean measurement times (± SD) were 13.5 (± 5.7), 45.7 (± 12.3), 18.5 (± 7.1), and 5.6 (± 1.0) seconds, respectively. CONCLUSIONS CCT measurements between OLCR-UP and OLCR-Pentacam are comparable and can be used interchangeably in clinical practice. However, SM underestimates CCT compared with the other methods, whereas Pentacam was found to be the least repeatable and took the longest time.
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Huang J, Lu W, Savini G, Hu L, Pan C, Wang J, Tan W, Chen J, Wang Q. Evaluation of corneal thickness using a Scheimpflug-Placido disk corneal analyzer and comparison with ultrasound pachymetry in eyes after laser in situ keratomileusis. J Cataract Refract Surg 2013; 39:1074-80. [PMID: 23680632 DOI: 10.1016/j.jcrs.2013.01.038] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2012] [Revised: 01/26/2013] [Accepted: 01/31/2013] [Indexed: 11/26/2022]
Abstract
PURPOSE To evaluate the repeatability and reproducibility of corneal thickness measurements in post-laser in situ keratomileusis (LASIK) eyes using a rotating Scheimpflug camera combined with a Placido disk corneal topographer (Sirius) and compare the results with those of ultrasound (US) pachymetry. SETTING Eye Hospital of Wenzhou Medical College, Wenzhou, China. DESIGN Comparative evaluation of a diagnostic test or technology. METHODS Patients were examined 3 times with the Scheimpflug-Placido topographer by 2 examiners. The central pupil corneal thickness (CTpupil), apical corneal thickness (CTapex), and thinnest corneal thickness (CTthinnest) were recorded. After noncontact examinations, US pachymetry was used to obtain the central corneal thickness (CCT). RESULTS The Scheimpflug-Placido topographer showed high intraoperator repeatability as indicated by a test-retest repeatability of less than 8.5 μm for CTpupil, CTapex, and CTthinnest, The coefficients of variation (CoV) were less than 0.7%, and the intraclass correlation coefficient was higher than 0.99. Excellent results were also obtained for interoperator reproducibility. All CoVs were less than 0.5%. The 95% limits of agreement between the Scheimpflug-Placido measurement and the US pachymetry measurements were narrow (-16.62 to 12.44 μm for CTpupil versus US pachymetry CCT; -17.49 to 12.16 μm for CTapex versus US pachymetry CCT; -18.59 to 10.90 μm for CTthinnest versus US pachymetry CCT). CONCLUSIONS The Scheimpflug-Placido topographer showed excellent intraoperator repeatability and interoperator reproducibility of CTpupil, CTapex, and CTthinnest measurements in post-LASIK eyes. The CCT measurements obtained using the device were in high agreement with those obtained by US pachymetry, suggesting that the 2 devices are interchangeable. FINANCIAL DISCLOSURE No author has a financial or proprietary interest in any material or method mentioned.
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Affiliation(s)
- Jinhai Huang
- School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical College, and the Key Laboratory of Vision Science, Ministry of Health PR China, Wenzhou, Zhejiang, China
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Jorge J, Rosado J, Díaz-Rey J, González-Méijome J. Central corneal thickness and anterior chamber depth measurement by Sirius(®) Scheimpflug tomography and ultrasound. Clin Ophthalmol 2013; 7:417-22. [PMID: 23467857 PMCID: PMC3587393 DOI: 10.2147/opth.s35121] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Background The purpose of this study was to compare the accuracy of the new Sirius® Scheimpflug anterior segment examination device for measurement of central corneal thickness (CCT) and anterior chamber depth (ACD) with that of CCT measurements obtained by ultrasound pachymetry and ACD measurements obtained by ultrasound biometry, respectively. Methods CCT and ACD was measured in 50 right eyes from 50 healthy subjects using a Sirius Scheimpflug camera, SP100 ultrasound pachymetry, and US800 ultrasound biometry. Results CCT measured with the Sirius was 546 ± 39 μm and 541 ± 35 μm with SP100 ultrasound pachymetry (P = 0.003). The difference was statistically significant (mean difference 4.68 ± 10.5 μm; limits of agreement −15.8 to 25.20 μm). ACD measured with the Sirius was 2.96 ± 0.3 mm compared with 3.36 ± 0.29 mm using US800 ultrasound biometry (P < 0.001). The difference was statistically significant (mean difference −0.40 ± 0.16 mm; limits of agreement −0.72 to 0.07 mm). When the ACD values obtained using ultrasound biometry were corrected according to the values for CCT measured by ultrasound, the agreement increased significantly between both technologies for ACD measurements (mean difference 0.15 ± 0.16 mm; limits of agreement −0.16 to 0.45 mm). Conclusion CCT and ACD measured by Sirius and ultrasound methods showing good agreement between repeated measurements obtained in the same subjects (repeatability) with either instrument. However, CCT and ACD values, even after correcting ultrasound ACD by subtracting the CCT value obtained with either technology should not be used interchangeably.
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Affiliation(s)
- J Jorge
- Clinical and Experimental Optometry Research Laboratory, Center of Physics (Optometry), School of Sciences, University of Minho, Braga
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Lamina cribrosa thickness is not correlated with central corneal thickness or axial length in healthy eyes. Graefes Arch Clin Exp Ophthalmol 2012; 251:847-54. [DOI: 10.1007/s00417-012-2145-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Revised: 07/04/2012] [Accepted: 08/11/2012] [Indexed: 10/27/2022] Open
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Ogbuehi KC, Osuagwu UL. Repeatability and interobserver reproducibility of Artemis-2 high-frequency ultrasound in determination of human corneal thickness. Clin Ophthalmol 2012; 6:761-9. [PMID: 22693418 PMCID: PMC3367432 DOI: 10.2147/opth.s31690] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Background The purpose of this study was to assess the repeatability and limits of agreement of corneal thickness values measured by a high-frequency ultrasound (Artemis-2), hand-held ultrasound pachymeter (DGH-500) and a specular microscope (SP-3000P). Methods Central corneal thickness (CCT) was analyzed in this prospective randomized study that included 32 patients (18 men and 14 women) aged 21–24 years. Measurements were obtained in two sessions, one week apart, by two examiners with three devices in a randomized order. Nine measurements were taken (three with each device) on one randomly selected eye of each patient in each measurement session. The coefficient of repeatability and interobserver reproducibility for the values of each method were calculated. The limits of agreement between techniques were also evaluated. Results There were no significant differences in CCT values between sessions for each of the three devices (P > 0.05). The repeatability coefficients for the Artemis-2 (±8 μm/±9 μm) were superior to those of the SP-3000P (±9 μm/±11 μm) and DGH 500 (±12 μm/±12 μm) in session 1/session 2 respectively, while the interobserver reproducibility index (differences between session 1 and session 2) was superior for the SP-3000P (±17 μm) with respect to DHG-500 (±29 μm) and the Artemis-2 (±31 μm). In session 1 and session 2, the limits of agreement between the techniques were 35 μm to −31 μm and 34 to −20 μm, respectively, for DGH-500 versus Artemis-2, 73 μm to 3 μm and 60 μm to 9 μm for Artemis-2 versus SP-3000P, and 58 μm to 22 μm and 72 μm to 10 μm for DGH-500 versus SP-3000P comparisons. The DGH-500 and Artemis-2 gave similar values (P > 0.05) in both sessions, but both (Artemis-2 and DGH-500) values were significantly greater than that of the SP-3000P (P < 0.05) in both sessions. Conclusion Repeatability was comparably good for the three techniques. However, interobserver reproducibility was approximately twice as good with the SP-3000P compared with the other two devices. The Artemis-2 CCT values consistently agreed with the DGH-500 and less so with the SP-3000P. The Artemis-2 provided CCT values that were, on average, 38 μm and 34 μm greater than that of the SP-3000P in session 1 and session 2, respectively.
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Affiliation(s)
- Kelechi C Ogbuehi
- Outpatient Clinic, Department of Optometry, King Saud University, Riyadh, Kingdom of Saudi Arabia
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Jansson U, Brautaset R, Cerviño A, Nilsson M. A comparison of the Canon TX-20P™ non-contact tonometer and pachymeter in healthy eyes. ACTA ACUST UNITED AC 2012. [DOI: 10.12968/ijop.2012.3.3.96] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Ulrika Jansson
- Unit of Optometry, Department of Clinical Neuroscience, Karolinska Institutet, Box 8056, 104 20 Stockholm, Sweden,
| | - Rune Brautaset
- Unit of Optometry, Department of Clinical Neuroscience, Karolinska Institutet, Box 8056, 104 20 Stockholm, Sweden,
| | | | - Maria Nilsson
- Unit of Optometry, Department of Clinical Neuroscience, Karolinska Institutet, Box 8056, 104 20 Stockholm, Sweden
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Topographic paracentral corneal thickness with pentacam and orbscan: effect of acoustic factor. Eye Contact Lens 2012; 37:348-53. [PMID: 21983548 DOI: 10.1097/icl.0b013e3182323dcf] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To evaluate the effect of an acoustic factor (AF) on the comparison of central corneal thickness (CCT) and peripheral corneal thickness (PCT) measurements with Orbscan II and Pentacam. METHODS The CCT and PCT at 1, 2, and 3 radial distances from the corneal apex were measured using Orbscan II and Pentacam in 22 right eyes of 22 healthy adults (7 men, 15 women). Three measures were obtained from each 1 of the 25 points measured and then compared to gauge the agreement between both devices at the corneal center and anular areas located at 1-, 2-, and 3-mm distances from the central measurement. Orbscan II readings were considered with and without an AF correction. RESULTS Pentacam provides statistically significant higher values than Orbscan II does at all the 25 locations analyzed (P<0.001). With a few exceptions, the average difference was fairly constant between 20 and 40 μm for all the corneal locations. A high correlation existed between central readings (r(2)=0.927; P<0.001) and average thickness at each one of the annular areas being analyzed (r(2)=0.897 at 1 mm, r(2)=0.876 at 2 mm, and r(2)=0.870 at 3 mm); Pentacam minus Orbscan II value averaged for all the points changed from -28±10 to -22±9 μm after the removal of the AF in Orbscan II. CONCLUSIONS Central and peripheral measurements of the corneal thickness obtained with Orbscan II and Pentacam are significantly different. The removal of the AF in Orbscan II renders lower mean differences but decreases the agreement between both systems and potentially induces an overestimation of CCT and PCT by Orbsan II compared with Pentacam.
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