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Abstract Background To assess repeatability and reproducibility of corneal epithelium thickness (ET) measured by a spectral-domain optical coherence tomographer (SD-OCT)/Placido topographer (MS-39, CSO, Florence, Italy) in keratoconus (KC) population at different stages, as well as to determine the progression limits for evaluating KC progression. Methods A total of 149 eyes were enrolled in this study, with 29 eyes in the forme fruste keratoconus (FFKC) group, 34 eyes in the mild KC group, 40 eyes in the moderate KC group, and 46 eyes in the severe KC group. Employing the within-subject standard deviation (Sw), test-retest variability (TRT), coefficient of variation (CoV), and intraclass correlation coefficient (ICC) to evaluate intraoperator repeatability and interoperator reproducibility. Results The repeatability and reproducibility of MS-39 in patients with KC were acceptable, according to ICC values ranging from 0.732 to 0.954. However, patients with more severe KC and progressive peripheralization of the measurement points had higher TRTs but a thinning trend. The current study tended to set the cut-off values of mild KC, moderate KC, and severe KC to 4.9 µm, 5.2 µm, and 7.4 µm for thinnest epithelium thickness (TET). When differences between follow-ups are higher than those values, progression of the disease is possible. As for center epithelium thickness (CET), cut-off values for mild KC, moderate KC, and severe KC should be 2.8 µm, 4.4 µm, and 5.3 µm. This might be useful in the follow-up and diagnosis of keratoconus. Conclusions This study demonstrated that the precision of MS-39 was reduced in measuring more severe KC patients and more peripheral corneal points. In determining disease progression, values should be differentiated between disease-related real changes and measurement inaccuracies. Due to the large difference in ET measured by MS-39 between various stages of disease progression, it is necessary to accurately grade KC patients to avoid errors in KC clinical decision-making.

AIM: To explore the value of corneal epithelial thickness parameters in the diagnosis of early keratoconus by Fourier domain optical coherence tomography(FD-OCT).METHODS: Retrospective control study. Patients with early keratoconus who were admitted to the Department of Ophthalmology of the First Affiliated Hospital of Soochow University from January 2015 to October 2020 and patients who received laser refractive surgery for myopia during the same period were included in this study. Using FD-OCT to measure the cornea in circle centralized by the pupil and with diameter of 9mm in the early-keratoconus group and the control group. This was to obtain the thickness parameter of corneal epithelium with diameter of 7mm, the respective averaged thickness value of corneal epithelium and the respective averaged thickness value of the full corneal layer on each of the 25 divisions. The parameter value differences between the early-keratoconus group and the control group were compared, and the diagnosis value of parameters that hold difference was analyzed. RESULTS: The Min-e value in early-keratoconus group was significantly lower than that of the control group. On contrary, the value of Std.Dev, Max-Min-e, and Max-e were significantly higher in early-keratoconus group than that in latter one(all P

Purpose: To compare agreement of corneal epithelium thickness (ET) between AS-OCT system (RTVue, Optovue) and AS-OCT/Placido topographer (MS-39, CSO) in eyes with different stages of keratoconus (KC), and to assess the repeatability of RTVue AS-OCT., Design: Prospective reliability analysis., Methods: KC eyes were classified into forme fruste KC (FFKC), mild, moderate, and severe KC. Agreement was evaluated with Bland-Altman plots and 95% limits of agreement (LoA). The repeatability of RTVue was assessed via within-subject standard deviation (S w ), test-retest variability (TRT), coefficient of variation (CoV), and intraclass correlation coefficient (ICC)., Results: A total of 119 KC eyes were enrolled, with 21 being FFKC, 26 mild, 39 moderate, and 34 severe. The 95% LoA ranged between -5.9 and 4.8 µm for center epithelium thickness (CET), between -5.7 and 8.2 µm for thinnest epithelium thickness (TET). At 1-mm measuring points, the 95% LoA of superior, inferior, nasal, and temporal were -4.2 to 4.7 µm, -5.2 to 6.0 µm, -7.9 to 10.2 µm, and -11.2 to 6.0 µm. At 3-mm measuring points, the corresponding values were -2.8 to 9.3 µm, -2.0 to 13.0 µm, -4.6 to 9.6 µm, and -6.3 to 9.7 µm, indicating that the 2 instruments were not interchangeable without adjustment. Despite that the repeatability of RTVue measurements in KC patients were acceptable, repeatability decreased gradually with the peripheralization of the measurement points., Conclusions: The 2 OCT-based devices, RTVue and MS-39, do not provide interchangeable measurements of epithelium thickness in KC patients. Repeatability decreases in cases of more severe KC, emphasizing the importance of grading before clinical examination to avoid diagnostic errors., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Purpose. To study the dynamics of tear production and morphometric parameters of cornea after phacoemulsification of senile cataract (SC) at different postoperative terms.Material and methods. 123 patients (123 eyes) aged from 62 to 83 years were examined after phacoemulsification of SC. All patients were divided into 2 groups depending upon the level of tear production (TP): 1st group – 61 patients with normal and insufficiently lowered TP, 2nd group consisted of 62 patients with moderate and severe TP suppression. Besides standard examination methods, all patients underwent Schirmer’s – 1 test, tear breakup time (TBUT), cornea OCT, corneal endothelial cell density (CECD) before operation and on the 1st, 10th , 20th and 30th postoperative day.Results. Indices of TBUT, corneal epithelium and stromal thickness (CET and CST), CECD turned out to be lower in the eyes of patients from the second group in comparison with the 1st.Conclusion. The conducted research showed that postoperative changes of CET occur 4 times and CST 1,5 times more often in patients with moderate and severe decrease of TP rather than in eyes with normal TP. The recovery of TP on the final stage of research was found 2.6 times less in eyes of patients from the 2nd group in comparison with the 1st, which can be the evidence of possible neurotrophic corneal disorders in patients with reduced TP.

Purpose: The purpose of this study is to investigate the epithelial thickness in the cornea and limbus in limbal stem cell deficiency (LSCD) using anterior segment optical coherence tomography (AS-OCT). Methods: This was a cross-sectional, comparative study. OCT images of 30 eyes of 19 patients with LSCD collected by AS-OCT were scanned. Corneal epithelial thickness was recorded at the central cornea and the superior, nasal, inferior, and temporal limbus. Measurment of the same region of 30 normal eyes served as control. Epithelial thickness in all locations was measured by 2 independent observers. Results: The mean epithelial layer thickness was 61.3 ± 2.9 μ in the central cornea and 62.7 ± 4.3 μ in the limbus in the control. The epithelial thickness in LSCD patients was found to be 41.33 ± 2.8 μ. An average reduction of 22.2% in the central cornea and 32.15% in the limbus was found in patients with LSCD (P < 0.05). Epithelial thinning correlated with the severity of LSCD in both cornea and limbus. In eyes with sectoral LSCD, a similar degree of epithelial thinning was also detected in the clinically unaffected limbal regions. Conclusion: Both corneal and limbal epithelia become progressively thinner in LSCD. Epithelial thickness assessment using AS-OCT as a noninvasive tool could be used as a diagnostic measure of LSCD.

Purpose: To study the corneal changes in rheumatoid arthritis (RA) patients in vivo, using spectral domain anterior segment optical coherence tomography (AS-OCT).Methods: A case-control study was done on 43 RA patients and 40 controls. The disease activity score (DAS28-ESR) was calculated and all participants had lower tear meniscus, corneal thickness, and epithelial thickness evaluation using AS-OCT.Results: The lower tear meniscus height (LTMH) and the lower tear meniscus area (LTMA) were significantly lower in the RA patients than in controls (p < 0.001). RA patients also had a significantly thinner central corneal thickness (p = 0.02) and their epithelium was found to be thinner in the superotemporal peripheral sector.Conclusions: The LTMH and LTMA are significantly reduced in RA patients, despite the absence of clinical diagnosis of dry eye. RA patients have thinner corneal thickness and epithelial thickness than controls, which did not correlate with either disease duration or activity. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study is to investigate the epithelial thickness in the cornea and limbus in limbal stem cell deficiency (LSCD) using anterior segment optical coherence tomography (AS-OCT).Methods: This was a cross-sectional, comparative study. OCT images of 30 eyes of 19 patients with LSCD collected by AS-OCT were scanned. Corneal epithelial thickness was recorded at the central cornea and the superior, nasal, inferior, and temporal limbus. Measurment of the same region of 30 normal eyes served as control. Epithelial thickness in all locations was measured by 2 independent observers.Results: The mean epithelial layer thickness was 61.3 ± 2.9 μ in the central cornea and 62.7 ± 4.3 μ in the limbus in the control. The epithelial thickness in LSCD patients was found to be 41.33 ± 2.8 μ. An average reduction of 22.2% in the central cornea and 32.15% in the limbus was found in patients with LSCD (P < 0.05). Epithelial thinning correlated with the severity of LSCD in both cornea and limbus. In eyes with sectoral LSCD, a similar degree of epithelial thinning was also detected in the clinically unaffected limbal regions.Conclusion: Both corneal and limbal epithelia become progressively thinner in LSCD. Epithelial thickness assessment using AS-OCT as a noninvasive tool could be used as a diagnostic measure of LSCD. [ABSTRACT FROM AUTHOR]

The corneal epithelium represents one of the main structures that undergo degenerative alterations due to antiglaucomatous therapy. Chronic glaucoma therapy containing benzalkonium chloride induces epithelial cellular changes and inflammatory infiltration that in turn causes ocular surface changes resulting in ocular discomfort. Also, age‐related changes can involve the tear film stability and the corneal epithelium surface with reduction of microvilli. The objective of this study is to gain insights about the changes in corneal epithelium in glaucomatous patients divided according to age, type and duration of therapy using anterior‐segment optical coherence tomography (AS‐OCT). This study evaluated a total of 81 eyes of 42 patients for whom corneal epithelium thickness (CET) was measured in different sectors of the cornea. Our results showed no significant differences in CET among patients divided according to type and duration of treatment, while younger patients showed a thinner CET in comparison with older patients. AS‐OCT results demonstrated that the physiological age‐related alterations contributed to corneal epithelium changes in patients undergo chronic antiglaucoma therapy. [ABSTRACT FROM AUTHOR]

Purpose: To study the relationship between epithelial thickness (ET) and corneal thickness (CT) in healthy fellow eyes of patients with unilateral bullous keratopathy (BKP) and healthy subjects., Methods: Seventeen BKP patients (nine males, eight females, 73.2±10.4 years) and 40 healthy individuals (20 males, 20 females, 69.5±9.8 years) were included. All participants received anterior segment optical coherence tomography and specular microscopy with calculation of endothelial cell density. ET, CT, stromal thickness and ET-to-CT ratio were defined automatically (within 2 mm central area). Central epithelial thickness (CET) and central corneal thickness (CCT) were measured manually at the corneal centre and stromal thickness and CET-to-CCT ratio were calculated., Results: In healthy fellow eyes of BKP patients compared with eyes of healthy individuals ET was statistically significantly lower (p<0.001) while CT was statistically significantly higher (by 28.9 and 30.9 µm in 2 mm zone and corneal centre, respectively). Both 2 mm ET-to-CT ratio (0.091±0.01 and 0.10±0.004, respectively [p<0.001]) and CET-to-CCT ratio (0.083±0.006 and 0.97±0.005, respectively [p<0.0001]) were statistically significantly lower in healthy fellow eyes of BKP patients compared with eyes of healthy individuals. To identify healthy fellow eyes of BKP patients, area under curve for CET-to-CCT ratio and CET was 0.94 and 0.80, respectively (p=0.01), and for 2 mm ET-to-CT ratio and 2 mm ET was 0.91 and 0.80, respectively (p=0.03)., Conclusion: Decreased СET-to-СCT ratio resulting from simultaneous epithelial thinning and stromal thickening without significant corneal thickening indicates subclinical dysfunction of corneal endothelium in healthy fellow eyes in unilateral BKP patients., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2020. No commercial re-use. See rights and permissions. Published by BMJ.)