Evaluation of the effect of intravitreal injections on corneal epithelial, scleral and limbal region changes in diabetic retinopathy by AS-OCT.

PURPOSE: The aim of the study is to evaluate the effects of diabetic retinopathy and intravitreal injections on the corneal, limbal and scleral areas. METHODS: Patients with diabetes mellitus at different diagnosis and treatment levels were compared among themselves and with the control group in terms of corneal, limbal and scleral aspects with the help of anterior segment optical coherence tomography. In addition, clinical tests such as tear break-up time, Schirmer test-I and ocular surface disease index questionnaire were applied to the patients and the difference between the groups was investigated. RESULTS: When the groups were examined in terms of BUT, SCH-I and OSDI, there was a statistically significant difference between control group and diabetic group(p < 0.05). In the limbal region, all measurements are higher than in patients with diabetic eye involvement. Thinning was detected in the scleral area with intravitreal injection (p < 0.05). CONCLUSION: It should be known that DM may cause undesirable changes in the limbal region, and the importance of non-invasive detection with AS-OCT should not be forgotten. Since intravitreal injections for DME cause thinning of the sclera, it can cause various complications, and it may be recommended to change the quadrant in repetitive injection applications.

NATURAL COURSE OF VITREOMACULAR TRACTION IN EYES WITH DIABETIC RETINOPATHY AND FACTORS ASSOCIATED WITH SPONTANEOUS RELEASE.

PURPOSE: The aim of this study was to determine the natural course of vitreomacular traction (VMT) in patients with diabetic retinopathy and to evaluate the factors associated with VMT relief. METHODS: Seventy-four eyes of 65 patients with VMT accompanying diabetic retinopathy were evaluated retrospectively. The presence of intravitreal injection and the presence of panretinal photocoagulation were obtained from the medical records of the patients. Spontaneous release of VMT, the horizontal length of vitreomacular traction, the presence of hyperreflective retinal spots, the presence of the epiretinal membrane, and the grade of VMT were evaluated from the spectral-domain optical coherence tomography images. Factors associated with the spontaneous release of VMT were evaluated by logistic regression analysis. RESULTS: Spontaneous release was observed in 28 eyes (37.8%). The horizontal length of VMT was lower in the release of the VMT group compared with the persistent VMT group (P = 0.03). The persistent VMT group had a higher rate of hyperreflective retinal spots and epiretinal membrane compared with the release of the VMT group (respectively; P = 0.003 and P = 0.031). No statistically significant difference was observed between the release of VMT and persistent VMT groups in terms of intravitreal injection and panretinal photocoagulation treatment (respectively; P = 0.938 and P = 0.36). The absence of hyperreflective retinal spots was the most important prognostic factor for the spontaneous release of VMT (P = 0.029). CONCLUSION: Spontaneous release of VMT observed higher rates of patients without hyperreflective retinal spots, epiretinal membrane, and patients with lower horizontal length of VMT.

Agreement of Anterior Segment Parameters Between Schiempflug Topography and Swept-Source Optic Coherence Based Optic Biometry in Keratoconus and Healthy Subjects.

PURPOSE: The aim of this study is to compare anterior segment parameters, including corneal thickness (CCT), keratometry and anterior chamber depth (ACD), and white to white corneal diameter (WTW), obtained by Pentacam Schiempflug imaging and intraocular lens (IOL) Master 700 swept-source optic coherence tomography biometry in keratoconus patients and healthy subjects. METHODS: This prospective cross-sectional instrument agreement analysis includes 88 eyes of 50 keratoconus patients and 87 eyes of 50 healthy subjects. Biometry was performed using IOL Master 700, and topography was performed using Pentacam. The keratometry values (Kf, Ks, Km, and Kmax), ACD, WTW, CCT, axial length (AL), anterior chamber angle (ACA), and lens thickness (LT) were evaluated. Levels of agreement between devices were evaluated by Bland-Altman plots with 95% limits of agreement. RESULTS: Intraocular lens Master 700 showed higher WTW, ACD, pupil diameter, and CCT values than Pentacam in both the keratoconus and control groups. However, there were no statistically significant differences in flat keratometry (Kf) and steep keratometry (Ks) values between the groups. CONCLUSION: Pentacam and IOL Master 700 may be used interchangeably in normal eyes and keratoconus eyes for the measurement of keratometry values and axis; however, these two devices should not be considered interchangeable for WTW, ACD, pupil diameter, and CCT measurements in both keratoconus patients and healthy subjects.

Corneal epithelium and limbal region alterations due to glaucoma medications evaluated by anterior segment optic coherence tomography: a case-control study.

AIM: To investigate the corneal epithelial and limbal epithelial alterations in patients under topical glaucoma treatment using anterior segment-OCT (AS-OCT) and to determine the changes of the limbal region due to the preservatives and glaucoma drugs, that can progress to limbal stem cell deficiency (LSCD). Limbal thickness was measured by AS-OCT to evaluate limbal cell deficiency. METHODS: Forty-seven patients using topical medication for glaucoma, and 48 control subjects were enrolled in this matched case-control study. The patients were divided into four groups according to the treatment regimens. Group 1: One-drug regimen, Group 2: Two-drug regimen, Group 3: Three-drug regimen, Group 4: Four-drug regimen For the ocular surface evaluation; tear break-up time with standard fluorescein sodium sterile strip application, Schirmer test-I, Ocular Surface Disease Index Questionnaire, and AS-OCT were performed. RESULTS: A total of 95 subjects were included: 47 eyes of 47 patients with glaucoma medication and 48 eyes of 48 healthy subjects. There was a statistically significant difference between patients and controls according to BUT, SCH, and OSDI (p < 0.001). The mean central corneal epithelium thickness was 48.5 ± 5.3 in patients and 54.5 ± 5.9 in controls (p < 0.001). The mean central total corneal thickness was 529.2 ± 41.2 in patients and 536 ± 35.3 in controls (p = 0.335). The mean limbal epithelium thickness was 64.1 ± 9.1 in patients and 76 ± 11.5 in controls (p < 0.001). CONCLUSION: Using at least one glaucoma drug caused limbal area injury, changed ocular surface measurements, and significantly reduced the limbal epithelial thickness where the stem cells reside. The limbal epithelial thickness measurement by AS-OCT seems to be an innovative, non-invasive, and promising technique for detecting and staging corneal damage in topical glaucoma therapy.