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OBJECTIVES: To evaluate scleral thickness measurements of pterygium patients using anterior segment optical coherence tomography (AS-OCT) and to compare them with healthy individuals. MATERIAL AND METHODS: Scleral thickness was measured from 2, 4, 6 mm posterior to the scleral spur with AS-OCT (Swept Source OCT Triton, Topcon, Japan) in 4 quadrants (superior, inferior, nasal and temporal). RESULTS: Eyes with pterygium were determined as Group 1, and contralateral eyes without pterygium were determined as Group 2. Healthy controls were determined as Group 3. In the measurements made from 4 mm posterior, no significant difference was found between Group 1 and Group 2 in any quadrants (p > 0.05). In all measurements made from 4 mm posterior to the scleral spur, scleral thickness was found to be significantly higher in Group 1 compared to Group 3 (p < 0.05). Measurements made from 2 mm posterior to the scleral spur in Group 1 was found to be significantly higher in the superior and temporal quadrants compared to Group 3 (p = 0.05), while no significant difference was found in the nasal and inferior quadrants (p > 0.05). When Group 2 and Group 3 were compared, scleral thickness measurements made from 4 mm posterior to the scleral spur was significantly thicker in all quadrants in Group 2 (p > 0.05). CONCLUSION: Scleral thickness was found to be higher in pterygium patients compared to healthy controls, especially when measured from 4 mm posterior to the scleral spur. It has been predicted that high scleral thickness may be associated with high fibroblast activity in subconjunctival structures, and this may predispose to pterygium.

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Purpose: To evaluate the effects of topical cyclopentolate hydrochloride-induced cycloplegia on anterior segment biomechanics in emmetropic eyes using anterior segment-optical coherence tomography (AS-OCT). Methods: Twenty-five emmetropic eyes of 25 volunteers were included. All underwent central corneal thickness (CCT) and anterior chamber depth (ACD) measurements. Anterior scleral thickness (AST) was measured at the level of the scleral spur (SS)(AST-0), 1,000 µm posterior of the SS (AST-1), and 2,000 µm posterior of the SS (AST-2) in the nasal and temporal quadrants using AS-OCT. All measurements were repeated after cycloplegia. Results: The mean age was 30.6 ± 12.4 (8-45) years. The mean CCT did not significantly change after cycloplegia (P = 0.7). The mean ACD was significantly increased [3.3 ± 0.2 (2.7-3.9) to 3.7 ± 0.3 (3-4.2) µm; P = 0.001]. In the nasal quadrant, the mean AST-1 and AST-2 were 512.3 ± 34.4 (433-570) and 529.6 ± 34.2 (449-599); decreased to 478 ± 26.8 (423-530) and 486.2 ± 28.3 (422-544) µm, respectively, after cycloplegia (P = 0.00; P = 0.00). In the temporal quadrant, the mean AST-1 and AST-2 were 522.5 ± 24.7 (473-578) and 527.2 ± 39.9 (450-604); decreased to 481.1 ± 33.7 (421-550) and 484.6 ± 26.6 (433-528) µm, respectively (P = 0.00; P = 0.00). There was no significant difference in AST-0 after cycloplegia in both quadrants [from 697.5 ± 46 (605-785) to 709.5 ± 64.7 (565-785) for nasal and from 718.4 ± 40.1 (632-796) to 722.9 ± 60.6 (596-838) for temporal; P = 0.2; P = 0.3, respectively]. Conclusion: After cycloplegia, there was a significant thinning of ASTs posterior to SS and a slight increase in AST in the SS level. ACD deepened after cycloplegia, and there was no significant change in CCT. Cycloplegic agents temporarily inhibit ciliary muscle contraction and may affect anterior segment parameters and sclera. Inhibition of forward-inward movement of the ciliary body by cycloplegia affects ASTs and ACD by causing a change in the mechanical force of the ciliary muscle on the sclera.

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PURPOSE: To evaluate scleral thickness using anterior segment-optical coherence tomography (AS-OCT) in Fuchs endothelial dystrophy (FED) and compare the results with healthy individuals. METHODS: Thirty-two eyes of 32 patients with FED and 30 eyes of 30 age, gender, spherical equivalent and axial length matched healthy participants were included. All subjects underwent a detailed ophthalmological examination including endothelial cell density and central corneal thickness (CCT) measurements. Scleral thickness was measured by AS-OCT (Swept Source-OCT, Triton,Topcon,Japan) in 4 quadrants (superior, inferior, nasal, temporal) from 6 mm posterior to the scleral spur. RESULTS: The mean ages were 62.5 ± 13.2 (33-81) for FED group; 64 ± 8.1 (48-81) for control group. CCT was significantly greater in FED group than in the control group (586.8 ± 33.1 (514-635) vs 545.0 ± 20.7 (503-587), respectively)(p = 0.000). In FED group, mean scleral thickness in the superior, inferior, nasal and temporal quadrants were 434.0 ± 30.6 (371-498), 442.8 ± 27.6 (395-502), 447.7 ± 31.4 (382-502), 443.4 ± 30.3 (386-504) µm, respectively. In control group, the mean scleral thickness in the superior, inferior, nasal and temporal quadrants were 381.3 ± 20.0 (341-436), 383.2 ± 16.0 (352-436), 389.2 ± 21.0 (353-440), 383.2 ± 19.2 (349-440) µm, respectively. The mean scleral thickness was significantly higher in all quadrants in FED group than in control group (p = 0.000). CONCLUSION: In patients with FED, scleral thickness was significantly higher. FED is a progressive corneal disease that results in the accumulation of extracellular material in the cornea. These findings suggest that the accumulation of extracellular deposits may not be limited to the cornea. Due to their functional similarity and anatomical proximity, sclera may also be affected in FED.

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PURPOSE: The purpose of this study was to evaluate the correlation between corneal astigmatism and the morphology of pterygium with anterior segment optic coherence tomography (AS-OCT). MATERIAL AND METHODS: The size of pterygium (horizontal length, vertical width) was measured manually; pterygium area and percentage extension of the pterygium onto the cornea were calculated. Anterior and posterior corneal astigmatism, Sim K, K1, K2 were measured using a dual Scheimpflug analyzer. Morphological patterns of the pterygium analyzed with AS-OCT were determined according to the extension of the pterygium apex below the corneal epithelium. Two tomographic patterns were identified: continuous and nodular. Correlation between anterior corneal astigmatism and pterygium size, percentage extension of the pterygium, and morphological pattern of the pterygium was analyzed. RESULTS: The mean ages of the 47 patients were 49.4 ± 16.6 (22-80) years. Mean horizontal pterygium length, vertical width, pterygium area, and percentage extension of the pterygium were 2.8 ± 1.2 mm, 4.8 ± 1.6 mm, 7.42 ± 5.6 mm2 and 24.5 ± 10.4%, respectively. Mean anterior corneal astigmatism was 2.3 ± 2.3 D and simulated keratometry was 43.4 ± 2.02 D. In terms of the morphological pattern of the pterygium, 24 eyes had continuous, 23 eyes had a nodular pattern and the median (interquartile range) anterior corneal astigmatism was 1.87 (1.01-3.80) and 1.22 D (0.58-2.35), respectively (p = 0.102). Other topographic and pterygium size parameters were similar between groups. Analyzing the correlations in groups separately, a positive moderate statistically significant correlation was present between vertical width, percentage extension, pterygium area, and anterior corneal astigmatism in both continuous and nodular groups. CONCLUSIONS: Although not statistically significant, anterior corneal astigmatism was higher in continuous group. Using AS-OCT to standardize the morphology of pterygium could provide additional clinical information.

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PURPOSE: To assess dry eye disease (DED) in thalassemic adolescents by evaluating corneal epithelial thickness (CET) and various dry eye clinical tests and correlate them to tissue iron overload. METHODS: The study included 120 Beta-thalassemia patients (11 to 18 years) and 120 matched controls. CET maps were captured using anterior segment optical coherence tomography. OSDI questionnaire was completed. Dry eye tests included Schirmer test, tear film breakup time (TBUT), and ocular surface staining (OSS) with fluorescein and lissamine green. We recorded serum ferritin level, and liver iron concentration (LIC) measured by magnetic resonance imaging. RESULTS: Superior and inferior CET was thinner, while map standard deviation (MSD) was higher in thalassemics compared to controls (all P <0.001 ). Thalassemic group also showed higher OSDI scores (P <0.001), shorter TBUT (P <0.001 ), and higher OSS grades (P <0.001 ). Both superior and inferior CET was correlated positively with TBUT, and negatively with OSS (all P < 0.001). Serum ferritin and LIC showed negative correlations with CET (superior and inferior, both P< 0.001), positive correlations with MSD, P< 0.001, as well as with TBUT (P< 0.001), OSS (P< 0.001), and OSDI scores (P< 0.001). CONCLUSION: Thalassemic adolescents had thinner CET with higher thickness' variability, shorter TBUT and more marked OSS than controls. Correlation of higher serum ferritin and hepatic iron overload with irregular epithelial thinning and more affected dry eye tests results supports our hypothesis that high tissue iron levels could play a pivotal role in DED pathogenesis in thalassemic patients.

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PURPOSE: To investigate the 5-year changes in static and dynamic anterior segment optical coherence tomography (AS-OCT) parameters and their predictors. METHODS: This was a prospective, population-based cohort study of people aged 50 years and older residing in the Liwan District, Guangzhou, China. Standardised AS-OCT scans were performed in November 2008 and November 2013 under dark and light conditions. Customised software was used to analyse horizontal AS-OCT images. Parameters in dark and measurements of light-to-dark changes were used for analyses. RESULTS: A total of 186 (71.8%) subjects underwent AS-OCT twice, 5 years apart and were included for analyses. The mean age in 2008 was 64.7±7.0 years, and 60.2% were women. The anterior chamber width (ACW) decreased from 11.74±0.44 mm in 2008 to 11.60±0.37 mm in 2013 (p=0.001). There was a trend towards a decrease in dynamic capacity (light-to-dark changes) in the anterior segment, with decreased iris thickness at 750 µm (ΔIT750), ΔACW, Δ anterior chamber area (ACA) and Δ pupil diameter at 5 years (all p<0.05). After adjusting for age and sex, the following baseline parameters were associated with a greater decrease rate in trabecular iris space area at 500 µm (TISA500) at 5 years: TISA500, IT750 and ACA in dark (p<0.001 for all). CONCLUSIONS: Anterior chamber angle width decreased and the amount of light-to-dark changes declined during 5-year follow-up. Subjects with greater height, wider angle width and thicker iris at baseline have greater angle narrowing at follow-up.

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OBJECTIVE: To provide a qualitative analysis of filtering blebs after being surgically repaired due to late blebs leaks. METHODS: Blebs were studied 6 months after surgical reparation using AS-OCT Triton (Topcon®). An analysis was made of the morphological pattern and internal structures of blebs, including the covering, in 10 patients. The images were obtained using OCTs at a wavelength of 1050nm. RESULTS: According to the Hirooka classification, three different patterns were found in the structure of blebs, which made it possible to correlate them with their functionality. A full covering was observed in 70% of the cases, and they showed sub-epithelial cysts (cystoid pattern). Two cases showed a full conjunctival retraction without Tenon's covering. The walls were thin, with a de-structured bleb (diffuse pattern) being visualised. In the third group, the image showed a partial conjunctival retraction with Tenon's covering. There were some sub-epithelial diffuse cysts with walls following a laminar pattern. CONCLUSION: Using AS-OCT, it is possible to study the bleb's characteristics in detail, as well as the cover, in the case of blebs requiring repair due to late leaks, using conjunctival advancement. It allows for the early visualisation of conjunctival retractions that were not visible in a slit lamp, and to predict the functionality of the blebs by their morphology.

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?AIM: To discuss the application of anterior segment optic coherence tomography ( AS-OCT ) in the diagnosis of corneal ulcer.?METHODS: The cross linear scan was used in 88 patients ( 88 eyes ) with corneal lesion by AS-OCT to gather the image data, observe the pathological changed tissue by measuring all layers for patients with initial inspection, providing important visual images and data for treatments. All the patients were followed up for 2mo.?RESULTS:Clear images with structure of all layers were obtained. It can provide the intuitive image data and scan the same position and show the changes during the treatment.?CONCLUSION: AS-OCT can discover the important condition immediately. It also can monitor course of disease dynamically, provide the intuitive image data for clinical treatment.