Diabetes is expected to accelerate age-related ganglion cell-inner plexiform layer (GC-IPL) loss, but there is limited information on the rate of reduction in GC-IPL thicknesses. We aimed to evaluate the reduction rate of GC-IPL thickness in diabetic patients, and to compare the rates between patients without and with diabetic retinopathy (DR). We included 112 eyes of 112 patients with diabetes [49 eyes without DR (no-DR group) and 63 eyes with mild to moderate non-proliferative DR (NPDR group)] and 63 eyes of 63 normal controls (control group) in this study. Macular GC-IPL thickness in all participants was measured for 3 years at 1-year intervals. The reduction rates of GC-IPL thickness were determined by linear mixed models and compared among the three groups. The estimated reduction rates of the average GC-IPL thickness in the no-DR (−0.627 μm/year) and NPDR (−0.987 μm/year) groups were 2.26-fold (p = 0.010) and 3.56-fold (p = 0.001) faster, respectively, than the control group (−0.277 μm/year). Age, duration of diabetes, and baseline average GC-IPL thickness were associated with longitudinal changes in average GC-IPL thickness. The GC-IPL reduction rate was significantly faster in diabetic patients, with and without DR. Physicians should therefore be aware that GC-IPL damage continues even if there is no DR. Diabetic retinopathy (DR), the most common complication of diabetes, is the leading cause of preventable visual impairment 1,2. In general, DR is clinically defined based on the observation of abnormal fundus vascular lesions, such as microaneurysms, hemorrhages, hard exudates, and cotton wool spots. However, experimental and clinical studies have shown that neurodegenerative changes, including loss of ganglion cells and glial reactivity, are also early events in the pathogenesis of DR 3-5. The loss of ganglion cells affects retinal ganglion cell layer and retinal nerve fiber layer (RNFL) thickness, and reduced thickness of these layers has been detected in clinical and animal studies 3,6-8. Optical coherence tomography (OCT) is a reliable method for quantitative structural evaluation of inner retinal layers, including of the thickness of the peripapillary RNFL (pRNFL) and macular ganglion cell-inner plexiform layer (GC-IPL), where such parameters could be useful for evaluating various conditions, such as retinal neuro-ophthalmic disease and glaucoma 9-11. Progressive changes in GC-IPL thickness can be identified by serial analysis of OCT measurements, and this trend-based analysis could be useful to understand the pathogenesis of certain conditions. Although microvascular abnormalities represent the classic hallmarks of DR, recent studies have reported that diabetic retinal neurodegeneration (DRN) occurs in patients without DR and DRN, which antecedes DR 12-15. The presence of age-related loss of retinal ganglion cells has been demonstrated histologically, and a progressive reduction in GC-IPL thickness, as measured by OCT, has also been reported 16. Abnormal systemic and eye conditions may accelerate th...

To determine the repeatability of superficial vessel density measurements using Spectral domain Ocular coherence tomography angiography(SD-OCTA) in patients diagnosed with retinal vein occlusion(RVO). Design Prospective observational study. Subjects Patients who visited our retinal clinic from August 2017 to August 2018, diagnosed with RVO were recruited for the study. Methods Two consecutive 3×3 mm pattern scans were performed using the Cirrus HD-OCT 5000 along with AngioPlex software (Carl Zeiss Meditec) in each eye by single skilled examiner. All scans were analyzed using en face OCTA images to measure vessel density (VD) automatically. For further analysis of the effect of central macular thickness(CMT), eyes were divided into two groups according to CMT of 400μm (Group 1: CMT > 400μm, Group 2: CMT < 400μm). To identify factors affecting the repeatability of VD measurements, linear regression analyses were conducted for the coefficient of variation (CV) of VD by investigating demographics and ocular variables. Main outcome measures The intraclass correlation coefficient (ICC), coefficient of variation (CV) of VD measurements.

Purpose: To determine the long-term repeatability of optical coherence tomography angiography (OCTA) parameters in normal eyes. Methods: We prospectively enrolled 104 normal eyes. Participants were divided into three groups based on differences in the signal strength (SS) of OCTA scans obtained at two visits at least 6 months apart: group 1, SS difference = 2; group 2, 1; group 3, 0. We measured a foveal centred scan area of 3 3 3 mm pattern. All measurements were performed twice at 5-min intervals at the initial visit. The second measurements were performed at least 6 months later. Results: In short-term vessel density (VD) repeatability, the coefficient of variation (CV) ranged from 3.89% to 8.10% and the intraclass correlation coefficient (ICC) ranged from 0.785 to 0.941. In terms of long-term repeatability, the CV was 5.39-12.62% and the ICC was 0.598-0.867. In group 1, the ICCs of the inner and full VDs were 0.194 and 0.221, respectively. In groups 2 and 3, the ICCs of the inner and full VDs were 0.611 and 0.603, and 0.763 and 0.765, respectively. The central VDs of all groups had high CV besides high ICC.Conclusions: Optical coherence tomography angiography parameters showed good short-term and reasonable long-term repeatability in normal individuals. The differences in SSs between measurements affected such repeatability, so physicians should query the reliability of OCTA parameters when the differences in SS are 2 or more even when the SS is high.

Purpose To identify the impacts of hypertension (HTN), high myopia, and the combination thereof on peripapillary retinal nerve fiber layer (pRNFL) thickness. Methods All subjects were divided into four groups: control (group 1); patients with HTN without high myopia (group 2); patients with high myopia without HTN (group 3); and patients with both HTN and high myopia (group 4). The pRNFL thicknesses were compared using a one-way analysis of variance. Univariate and multivariate linear regression analyses were used to identify factors affecting pRNFL thickness in subjects with and without HTN. Results The mean pRNFL thicknesses were 93.9±8.8, 88.7±6.8, 86.4±8.1, and 82.5±9.6 μm in group 1, 2, 3, and 4, respectively, and differed significantly (P<0.001). On multivariate linear regression analyses, age (β = -0.181, P = 0.044), axial length (β = -1.491, P<0.001), and HTN (β = -4.876, P = 0.044) significantly affected pRNFL thickness. Additionally, age and axial length affected the pRNFL thickness in subjects with HTN (age, β = -0.254, P = 0.020; axial length, β = -1.608, P<0.001) much more than in subjects without HTN (age, β = -0.028, P = 0.712; axial length, β = -1.324, P<0.001). Conclusions High myopia and HTN affected pRNFL reduction and a combination of the 2 diseases exacerbated pRNFL damage. This could be a confounding factor in interpreting pRNFL thickness in patients with ophthalmic diseases affecting the pRNFL thickness when combined with the 2 diseases.

To analyze longitudinal changes in peripapillary retinal nerve fiber layer (pRNFL) thicknesses over time in the fellow eyes of patients with unilateral retinal vein occlusion (RVO). A total of 47 patients with unilateral RVO and 47 healthy controls were enrolled. The mean and sectoral pRNFL thicknesses were measured using spectral domain-optical coherence tomography at 1 year intervals, and followed for 3 years. Linear mixed models were performed to calculate and compare the reduction rates of pRNFL thicknesses over time. The mean pRNFL thickness decreased significantly during the 3-year follow-up, with a significant decrease over time in both groups. The reduction rate in mean pRNFL thicknesses was −0.41 μm/year in the control group and −0.68 μm/year in the fellow eyes of RVO group, and the decrease was significantly higher in the fellow eyes of RVO group than in the control group (p < 0.001). Using a multivariate linear mixed model, age (estimate: −0.41, p = 0.011) and hypertension (HTN) (estimate: −6.51, p = 0.014) were significantly associated with the reduction in mean pRNFL thicknesses in fellow eyes of RVO group. The fellow eyes of RVO patients showed a greater reduction in pRNFL thickness over time than normal controls. Age and HTN should be considered as factors to decrease the pRNFL thickness over time in fellow eyes of RVO group.