Evaluation of Central Corneal Epithelial Thickness With Anterior Segment OCT in Patients With Type 2 Diabetes Mellitus

Aim: The aim of this study was to evaluate the central corneal thickness (CCT) and central corneal epithelial thickness (CCET) in patients with Type 2 diabetes mellitus (DM), and the effect of the duration of diabetes, the degree of diabetic retinopathy (DR), and HbA1c level. Method: CCT and CCET values ​​of 72 patients diagnosed with type 2 DM and 72 healthy individuals were measured by anterior segment optical coherence tomography (AS-OCT). The eye tear function was evaluated with the Tear Break-up Time test (TBUT) and the Schirmer test. From the results of fundus examination, the diabetic patients were grouped as those without DR, with non-proliferative DR, and with proliferative DR. The disease duration and the HbA1c levels were recorded. Results: In the diabetic patients, the mean CCT was determined to be thicker (p=0.025), the CCET was thinner (p=0.003), and the TBUT and Schirmer values were lower (p<0.001, p<0.001, respectively). The duration of diabetes and the HbA1c level were not found to have any statistically significant effect on these parameters (p>0.05). The presence of retinopathy had no significant effect on CCT, TBUT and Schirmer values. The CCET was determined to be thinner in patients with retinopathy (p<0.001). Conclusion: As the corneal epithelial thickness is reduced in patients with advanced diabetic retinopathy, corneal epithelial pathologies can be seen more often. Therefore, early and effective treatment can be started taking into consideration the complications which may develop associated with the corneal epithelium following surgical procedures, especially those applied to the cornea.

Long-Term Follow-Up of Accelerated Transepithelial Corneal Crosslinking for Post-LASIK Ectasia: A Pilot Prospective Observational Study

Background: Keratectasia after corneal refractive surgery is a rare but serious postoperative complication, and reports on accelerated transepithelial corneal crosslinking (ATE-CXL)-based treatment of patients with post-laser-assisted in situ keratomileusis (LASIK) ectasia are limited. Therefore, this study evaluated the long-term efficacy and safety of ATE-CXL for progressive post-LASIK ectasia.Methods: This prospective observational study was conducted at the Eye and ENT Hospital, Fudan University, Shanghai, China, and 25 eyes from 25 patients with post-LASIK ectasia undergoing ATE-CXL were examined. Clinical examinations were conducted preoperatively and postoperatively to assess parameters such as manifest refraction, corrected distance visual acuity (CDVA), endothelial cell density; keratometry, corneal thickness, posterior elevation and topometric indices were measured using Pentacam; sectoral pachymetry and epithelial thickness were evaluated using optical coherence tomography. A paired t-test, Wilcoxon rank-sum test, Kruskal-Wallis test, and repeated measures analysis of variance were used for statistical analysis.Results: Participants were examined for an average of 46 months. No severe complications occurred during or after ATE-CXL. CDVA improved from 0.25 ± 0.31 preoperatively to 0.15 ± 0.17 postoperatively (p = 0.011). Maximum keratometry decreased from 55.20 ± 8.33 D to 54.40 ± 7.98 D, with no statistical significance (p = 0.074), and the central corneal thickness increased from 414.92 ± 40.96 μm to 420.28 ± 44.78 μm (p = 0.047) at the final follow-up. Posterior elevation, pachymetry, and epithelial thickness remained stable (p &gt; 0.05) throughout the follow-up. No significant differences were noted in topometric indices, except the central keratoconus index, which decreased significantly (p &lt; 0.001) at the final follow-up.Conclusion: Improvements in CDVA and stabilization in corneal keratometry and posterior elevation after ATE-CXL were noted at the 46-months follow-up, demonstrating that ATE-CXL is a safe and effective treatment for progressive post-LASIK ectasia.

Corneal and Epithelial Thickness Mapping: Comparison of Swept-Source- and Spectral-Domain-Optical Coherence Tomography

Objective. To compare the results and repeatability of the corneal thickness (CT) and epithelial thickness (ET) maps provided by Swept-Source-Optical Coherence Tomography with those of Spectral-Domain-OCT in normal eyes. Methods. 30 normal eyes of 30 patients were assessed by 3 trained operators with SS-OCT and SD-OCT. Results. The central and minimum ET obtained with both devices were correlated: central ET, r = 0.86, p < 0.05 ; minimum ET, r = 0.72, p < 0.05 . Compared with SD-OCT, SS-OCT tended to underestimate these figures by 1.4 and 1.9 μm on average. The central and minimum CT obtained with both devices were strongly correlated: central CT, r = 0.994, p < 0.05 ; minimum CT, r = 0.995, p < 0.05 . SS-OCT tended to overestimate these figures by 11 and 14 μm on average. Repeatability was good for both devices with a mean coefficient of variation of measurements <6% for ET and <2% for CT. Interoperator variability (standard deviation and COV) was significantly higher for SS-OCT than for SD-OCT for all local epithelial thicknesses and significantly lower for the central CT and several local corneal thicknesses, whereas no significant differences between both technologies were found for the central and minimum ET and the minimum CT. Conclusion. SS-OCT and SD-OCT provide reproducible measurements of CT and ET in normal corneas with a strong correlation between both technologies. However, both technologies are not interchangeable when the main thickness parameters (i.e., central and minimum CT and minimum ET) are used for diagnosing early keratoconus or calculating the expected residual stromal bed thickness before corneal refractive surgery or anterior lamellar keratoplasty.

Corneal epithelial mapping in different corneal conditions

Background Cataract surgery is traumatic to the corneal epithelium,scarring and opacity is the commonest cause of blindness. Objective To study the corneal epithelial thickness in different corneal conditions using anterior segment optical coherence tomography (AS-OCT). Patients and Methods A case-control study including 80 eyes divided equally into 4 groups; group 1:controls,group 2:corneal scarring ,group 3:cataract patients and group 4:pterygium. using AS-OCT epithelial mapping to document changes in epithelial thickness in controls, cataract patients pre and 1 month after phacoemulsification, patients with corneal scarring and patients with pterygium. Results In phacoemulsification group; we found that epithelial thickness became thinner in area (0_2) and thicker in area (7_9) mm in the map with no significant change in areas (2_5),(5_7) mm in the map. In corneal scarring group; we found that epithelial thickness became thicker compared to control group in all zones. In pterygium group; we found that epithelial thickness became thicker compared to control group in, areas (2_5), (5_7) & (7_9) mm in the map with no significant change in area (0_2) mm in the map. Conclusion The corneal epithelium thickness becomes thinner or thicker to compensate for changes in stromal thickness.

The role of epithelial thickness mapping in corneal refractive surgery

Refractive surgery has stimulated significant progress in anterior segment imaging. Knowledge of epithelial thickness profile considerably increases the efficacy and safety of refractive procedures. This review aims to present new technologies evaluating corneal epithelial thickness and the most important clinical applications in the field of corneal refractive surgery.

Innovative Treatment Using Salmon Skin Extract as Topical Application for Traumatic Oral Ulcer Healing: Animal Models

Salmon skin extract contains high proline and hydroxyproline, and has been suggested as a potential topical agent for traumatic oral ulcer healing. The aim of this study was to evaluate the effect of salmon skin extract as traumatic oral ulcer healing. A total of 32 Wistar rats (200 g to 250 g) were distributed into four groups. Group 1 served as the control group (no treatment), Group 2 was topically treated with salmon skin extract agent 4%, Group 3 was topically treated with salmon skin extract agent 5%, and Group 4 was topically treated with salmon skin extract agent 6%. Traumatic ulcers at lip mucosa were performed in all rats and 0.1 ml salmon skin extract was applied on the ulcer twice daily for seven days. The animals were euthanised on the last day of treatment. Biopsy specimens were taken from the lip mucosa in all rats for epithelial thickness evaluation and the study for number of fibroblasts by histological analysis. Significant increase in epithelial thickness and the number of fibroblasts (p > 0.05) was observed in salmon skin extract treatment groups as compared to the control group. Salmon skin extract 6% treatment group had the highest epithelial thickness and the number of fibroblasts amongst the study groups. Salmon skin extract promises an innovative topical application treatment for traumatic oral ulcer healing. Salmon skin extract 6% was the most effective concentration for traumatic oral ulcer healing.