Early neurovascular changes in the retina in preclinical diabetic retinopathy and its relation with blood glucose.

BACKGROUND: To investigate the changes in retinal nerve fiber layer thickness and macular blood flow density during the preclinical stage of diabetic retinopathy and their relationship with blood glucose. METHODS: In this cross-sectional study, 97 diabetic patients (total of 188 eyes; 144 eyes in no diabetic retinopathy group, 44 eyes in mild diabetic non-proliferative retinopathy group) and 35 healthy people (70 eyes) were enrolled, All the subjects were divided into different groups based on their HbA1c levels, and they underwent optical coherence tomography angiography. We compared the optical coherence tomography angiography parameters and retinal nerve fiber layer thickness among the different glucose groups. RESULTS: The parafoveal vessel density and the temporal retinal nerve fiber layer thickness were lower (p < 0.05) in the diabetic group than in the normal group. The diabetic group showed a higher acircularity index than the normal group. The normal group had the highest vessel density and the lowest acircularity index, followed by the no-diabetic retinopathy group and the mild non-proliferative retinopathy group, (p < 0.001). Foveal vascular density and parafoveal vessel density decreased with an increase in HbA1c. There was a negative correlation between parafoveal vessel density in the deep retinal vascular layer and fasting blood glucose (p < 0.01). The temporal retinal nerve fiber layer thickness decreased across the HbA1c level groups, and was positively correlated with the parafoveal vessel density in the superficial retinal vascular layer (p < 0.05). CONCLUSIONS: This study shows that retinal microvasculopathy and neuropathy can be present in the absence of retinopathy. The vessel density of the deep retinal vascular layer was negatively correlated with fasting blood glucose, and the temporal retinal nerve fiber layer thickness was positively correlated with the vessel density of the superficial retinal vascular layer. These indicators are helpful for endocrinologists and ophthalmologists in detecting early diabetic retinal pathological lesions.

Retinal Structure Abnormalities in Parkinson's Disease and Atypical Parkinsonism.

We investigated retinal structure changes in patients with Parkinson's disease (PD), multiple system atrophy (MSA), progressive supranuclear palsy (PSP), and controls, and explored the value of this method in differential diagnosis. Spectral domain optical coherence tomography (SD-OCT) was used to measure peripapillary retinal nerve fiber layer (pRNFL) thickness, and macular thickness and volume. PSP patients showed higher temporal pRNFL thickness than PD and MSA patients. Peripapillary RNFL thickness could be used for discriminating PSP from MSA and PD. PD and MSA patients showed retinal thinning in the foveal center circle and nasal inner sectors compared to controls. Macular thickness and volume could be used for discriminating MSA from PD. There were negative correlations between disease duration and OCT parameters in PD, MSA, and PSP, independent of age, sex ratio, and the side of the eye. PD and atypical parkinsonism correlate with specific patterns of retina alterations. OCT could be a biomarker for differential diagnosis and progression evaluation of parkinsonian syndrome.

Treatment and longitudinal follow-up of CNV associated with pattern dystrophy with novel PRPH2 variant.

BACKGROUND: Peripherin-2 (PRPH2) is a transmembrane glycoprotein crucial for the morphogenesis and stabilization of the photoreceptor outer segments. Variations in PRPH2 gene are associated with vision-threatening diseases. METHODS: Clinical manifestations and multimodal imaging were presented, as well as treatment history and six-year follow-up. In addition, genetic testing was performed to confirm the diagnosis. RESULTS: In this report, we present an extremely rare case of choroidal neovascularization (CNV) secondary to pattern dystrophy simulating fundus flavimaculatus (PDSFF). Multimodal imaging showed typical symmetric yellow flecks in posterior pole and choroidal neovascularization requiring timely treatment. A novel nonsense variant of c.552 C > G; p.Y184X in PRPH2 gene was detected. The patient received intravitreal anti-vascular endothelial growth factor (anti-VEGF) treatment and maintained a good vision after six years. CONCLUSION: We described a novel PRPH2 variant (Y184X) associated with PDSFF, its multimodal imaging, and long-term prognosis. Intravitreal anti-VEGF treatment can offer excellent visual prognosis in patients with PDSFF-associated CNV.

Correlation between the Nonperfusion Area on Ultra-Widefield Fluorescein Angiography and Nonflow Area on Optical Coherence Tomographic Angiography in Retinal Vein Occlusion.

AIMS: To compare the relationship between the nonperfusion area (NPA) on ultra-widefield fluorescein angiography (UWFFA) and the nonflow area (NFA) on optical coherence tomographic angiography (OCTA) in retinal vein occlusion (RVO). METHODS: Cross-sectional study. 46 eyes of 46 RVO patients who underwent UWFFA and OCTA. NPA and ischemic index (ISI) were quantified on UWWFA. NFA, vessel density (VD) of the superficial capillary plexus (SCP), the deep capillary plexus (DCP), and the size foveal avascular zone (FAZ) on 3 ∗ 3 mm OCTA were measured. The association of the NPA and ISI on UWWFA and the parameters on OCTA were analyzed. Spearman correlation was used for statistical testing. RESULTS: The NPA and ISI on UWFFA were significantly correlated with the NFA on OCTA in RVO, and r values were 0.688 (p < 0.01) and 0.680 (p < 0.01), respectively. VD in the SCP of the temporal quadrant was negatively correlated with NPA and ISI, and r values were -0.346 (p < 0.05) and -0.337 (p < 0.05), respectively. VD in the DCP of the temporal quadrant was negatively correlated with the NPA, and the r value was -0.246 (p < 0.05). No significant correlation was found between the NPA and ISI on UWFFA and VD of other quadrants in the SCP or DCP and the FAZ area on OCTA. CONCLUSION: NPA in the peripheral retina was correlated with NFA in macula. NFA detected by OCTA could be an indicator of the ischemic status in RVO.

Quantification of Microvascular Density of the Optic Nerve Head in Diabetic Retinopathy Using Optical Coherence Tomographic Angiography.

AIMS: To quantify the capillary density of the optic nerve head in healthy control eyes and different stages of diabetic retinopathy (DR) eyes and identify the parameters to detect eyes with or without DR using optical coherence tomographic angiography (OCTA). METHODS: In this cross-sectional study, 211 eyes of 121 participants with type 2 diabetes with different stages of DR or without DR and 73 eyes of 38 healthy age-matched controls were imaged by OCTA. Radial peripapillary capillary (RPC) plexus density and retinal nerve fiber layer (RNFL) thickness were examined. The mixed model binary logistic regression model was used to identify the parameters to detect eyes with or without DR. The area under the receiver operating characteristic (ROC) curve was calculated. RESULTS: RPC density decreased significantly in diabetic patients without DR compared with the healthy controls, and it was negatively correlated with the severity of DR (P < 0.01). RPC density was a significant parameter to distinguish diabetic eyes with or without DR (P < 0.01). The area under the ROC curve was 0.743. CONCLUSIONS: Quantification of RPC density by OCTA provides evidence of microvascular changes in the optic nerve in diabetic patients. RPC density can serve as a possible biomarker in detecting eyes with DR. Larger cohort studies need to support this statement.