Anemia is the most common hematological disorder noted in the people of the Indian subcontinent. Hemodynamic changes following anemia on the retina and choroid are not frequently studied. The aim of the study was to analyse the subfoveal retinal (CRT) and choroidal (SFCT) thickness changes in patients with anemia. In this retrospective, comparative study, patients who were diagnosed with primary anemia and had a fundus examination by a retinal specialist were included. Patients were divided into 3 groups: Group 1: Patients with anemic retinopathy; Group 2: Patients with anemia without retinopathy; Group 3: Normal healthy controls. One hundred and ninety-seven eyes of 197 subjects (group 1 - 38 eyes, group 2 - 90 eyes; group 3 - 69 eyes) met the inclusion criteria. Mean CRT was 269 ± 117µm, 258 ± 99.7µm and 201 ± 19.2µm and SFCT was 303 ± 68.4µm, 303 ± 50.1µm and 275 ± 38.9µm in groups 1, 2 and 3 respectively. Low haemoglobin corelated negatively with retinal (r = -0.362; p = <0.001) and choroidal (r = -0.294; p = <0.001) thickening and reduced visual acuity (r = -0.157; p = 0.03). In conclusion, patients with anemia have a thicker retina and choroid compared to normal healthy controls.

The neuroretina is a functional unit of the central nervous system that converts a light signal into a nerve impulse. Of neuroectodermal origin, derived from the diencephalon, the neuroretina is a layered tissue composed of six types of neuronal cells (two types of photoreceptors: cones and rods, horizontal, bipolar, amacrine and ganglion cells) and three types of glial cells (Müller glial cells, astrocytes and microglial cells). The neuroretina lays on the retinal pigmentary epithelium, that together form the retina. The existence of the internal and external blood-retinal barriers and intra-retinal junctions reflects the fineness of regulation of the retinal exchanges with the circulation and within the retina itself. The central zone of the human retina, which is highly specialized for visual acuity, has anatomical specificities. Recent imaging methods make it possible now to enrich our knowledge of the anatomical and functional characteristics of the retina, which are still imperfectly described.

PURPOSE:This study aimed to compare the choroidal vascularity index (CVI) of eyes having Fuchs' uveitis syndrome (FUS) with healthy fellow eyes (N). METHODS:This prospective, cross-sectional study included unilateral FUS cases and an age- and gender-matched healthy control group. Thirty-nine participants were included in the FUS group, and 24 age- and gender-matched individuals were randomly selected for the control group. Endothelial cell density (ECD) was measured using Tomey specular microscopy. Spectral-domain optical coherence tomography was used to acquire the choroidal images, and binarization was applied to the images. Two blinded investigators analyzed the CVI in both eyes of the FUS cases and the right eyes of the healthy control group. RESULTS:CVI was found to be significantly decreased in FUS (p < 0.001). Additionally, ECD had a strong positive correlation with CVI (r = 0.383, p = 0.008). CONCLUSION:CVI may provide information about the chronicity of the disease.

Remarkable improvements in optical coherence tomography (OCT) technology have resulted in highly sophisticated, noninvasive machines allowing detailed and advanced morphological evaluation of all retinal and choroidal layers. Postproduction semiautomated imaging analysis with dedicated public-domain software allows precise quantitative analysis of binarized OCT images. In this regard, the choroidal vascularity index (CVI) is emerging as a new imaging tool for the measurement and analysis of the choroidal vascular system by quantifying both luminal and stromal choroidal components. Numerous reports have been published so far regarding CVI and its potential applications in healthy eyes as well as in the evaluation and management of several chorioretinal diseases. Current literature suggests that CVI has a lesser variability and is influenced by fewer physiologic factors as compared to choroidal thickness. It can be considered a relatively stable parameter for evaluating the changes in the choroidal vasculature. In this review, the principles and the applications of this advanced imaging modality for studying and understanding the contributing role of choroid in retinal and optic nerve diseases are discussed. Potential advances that may allow the widespread adoption of this tool in the routine clinical practice are also presented.

PURPOSE:To compute choroidal vascularity index (CVI) using an image binarization tool on enhanced depth imaging (EDI)-optical coherence tomography (OCT) scans as a non-invasive optical tool to monitor progression in panuveitis and to investigate the utility of volumetric data from EDI-OCT scans using custom image analysis software. MATERIALS AND METHODS:In this retrospective cohort study, segmented EDI-OCT scans of both eyes in 19 patients with panuveitis were taken at baseline and at 3-month follow-up and were compared with EDI-OCT scans of normal eyes. Subfoveal choroidal area was segmented into luminal (LA) and stromal interstitial area (SA). Choroidal vascularity index (CVI) was defined as the proportion of LA to the total circumscribed subfoveal choroidal area (TCA). RESULTS:The mean choroidal thickness was 265.5±100.1μm at baseline and 278.4±102.6μm at 3 months follow up (p = 0.06). There was no statistically significant difference in TCA between study and control eyes (p = 0.08). CVI in the control group was 66.9±1.5% at baseline and 66.4±1.5% at follow up. CVI was 74.1±4.7% at baseline and 69.4±4.8% at 3 months follow up for uveitic eyes (p<0.001). The % change in CVI was 6.2 ±3.8 (4.3 to 8.0) for uveitic eyes, which was significantly higher from % change in CVI for control eyes (0.7±1.1, 0.2 to 1.3, p<0.001). CONCLUSION:The study reports composite OCT-derived parameters and CVI as a possible novel tool in monitoring progression in panuveitis. CVI may be further validated in larger studies as a novel optical tool to quantify choroidal vascular status.

Purpose:To investigate the longitudinal changes in choroidal vascularity index (CVI) in eyes with active and quiescent intermediate uveitis using enhanced depth imaging optical coherence tomography (EDI-OCT). Methods:EDI-OCT images of eyes with active and quiescent intermediate uveitis were retrospectively reviewed and binarized using ImageJ software. Choroidal parameters including CVI, total choroidal area (TCA), luminal area (LA), stromal area (SA), and subfoveal choroidal thickness (SCT) were measured and compared between baseline and follow-up visits among eyes with active and quiescent intermediate uveitis. Results:Thirty-eight eyes from 21 patients with active intermediate uveitis and 30 eyes from 17 patients with quiescent intermediate uveitis were included. CVI in eyes with active intermediate uveitis significantly increased from baseline (66.50% ± 3.40%) with resolution of inflammation on follow-up (68.82% ± 3.90%; P < 0.001). In eyes with quiescent intermediate uveitis at baseline eyes, CVI did not significantly change after follow-up (66.34% ± 3.19% to 66.25% ± 3.13%; P = 0.850). Conclusions:CVI significantly increased when active inflammation in intermediate uveitis resolved while CVI remained unchanged at follow-up in quiescent intermediate uveitis. Translational Relevance:CVI may be a useful noninvasive tool to monitor treatment response in intermediate uveitis. Our findings also highlight the involvement of choroidal vasculature in uveitic eyes without any clinical evidence of choroiditis.