Evaluation of Foveal Avascular Zone and Capillary Plexuses in Diabetic Patients by Optical Coherence Tomography Angiography

PURPOSE: To investigate the foveal avascular zone (AVZ), superficial and deep foveal and parafoveal vessel density (VD) changes related to diabetic retinopathy. METHODS: Forty-nine type 2 diabetes mellitus (DM) and 45 healthy control subjects were included in this study. The demographic data (age and sex), disease duration, and level of glycated hemoglobin were collected. Superficial VD (%), superficial AVZ area (mm2), deep VD (%) and deep AVZ area (mm2) were evaluated via optic coherence tomography angiography. RESULTS: Superficial AVZ was 0.438 ± 0.05 mm2 in the DM group, 0.246 ± 0.022 mm2 in the control group (p < 0.001). Deep AVZ was 0.732 ± 0.06 mm2 in the DM group, and 0.342 ± 0.022 mm2 in the control group (p < 0.001). Superficial foveal VD was 29.45 ± 0.76 mm2 in the DM group, and 34.86 ± 0.75 mm2 in the control group (p < 0.001). Deep foveal VD was 24.85 ± 1.08 mm2 in the DM group, and 33.47 ± 0.56 mm2 in the control group (p < 0.001). CONCLUSIONS: In this study, we demonstrated an enlargement in the foveal AVZ along with a reduction in the vascular density of the superficial and deep capillary network in the foveal and parafoveal area using optic coherence tomography angiography in patients with nonproliferative diabetic retinopathy. This technique can be used to monitor the progression of the disease and to evaluate the response to treatment.

Comparing the effects of two different contact lenses on corneal reepithelialization after corneal collagen cross-linking

Objective: To investigate whether keratoconus [KC] patients who applied the corneal collagen cross-linking [CXL] and two different contact lens [CL] showed any differences in complaints and findings following the CXL

Methods: This prospective, comparative, double-blind clinical study involved 60 eyes of 60 patients [38 female and 22 male]. At the end of the CXL procedure, CL [Balafilcon A] was inserted in 29 patients [Group-1] while CL with different material content [Hioxifilcon A] designed for therapeutic/bandage purposes were inserted in 31 patients [Group-2]

Results: On the 1[st] and 3[th] day after the CXL, there were no statistically significant differences between the groups in terms of the postoperative symptoms. On the 3[th] day after the CXL, all cases of both two groups were found to complete the corneal re-epithelialization. There was more PE ratio in the patients who had allergic conjunctivitis

Conclusions: With the use of Balafilcon A and Hioxifilcon A lens materials, KC patients who underwent the CXL were found to have similar symptoms and clinical findings after the CXL. However, epithelial staining and PE were observed more in KC cases accompanied by allergic conjunctivitis

Corneal topography analysis of stromal corneal dystrophies

The aim was to compare the corneal topography and tomography parameters of macular corneal dystrophy [MCD], granular corneal dystrophy [GCD] and lattice corneal dystrophy [LCD] patients obtained by Scheimpflug imaging system. The charts, photographs and topography images of patients were reviewed retrospectively. This study included 73 eyes of 73 patients [28 MCD, 20 GCG and 25 LCD patients]. Topography images were obtained by Pentacam [Oculus Optikgerate, Wetzlar, Germany]. The densitometry readings at the corneal apex were used for the statistics. The female to male ratio was 13/15 in MCD group, 12/8 in GCD group and 13/12 in LCD group. The mean age median age was 32, 45 and 53 years in MCD, GCD and LCD groups respectively. The groups were similar regarding the gender [p=0.861]. The MCD group was significantly younger than the other two groups [p<0.001]. The median [minmum-maximum] corneal densities were 100 [100-100], 68 [17-100] and 97 [34-100] Pentacam densitometry units in MCD, GCD and LCD groups respectively. The corneal density at the corneal apex was significantly higher in MCD group than in the other groups [p<0.001]. The GCD and LCD groups were statistically similar in terms of density of the corneal apex [p=0.079]. In MCD group, corneal thickness at the apex and at the thinnest location was significantly thinner, than in the other groups [p=.002 for thickness at apex between MCD and LCD, and p<.001 for all the remaining comparisons]. In MCD group corneal volume was significantly smaller than in the other groups [p<.001 for all comparisons]. Densitometry on Scheimpflug imaging system gives information on the density of corneal opacities