PURPOSE. The purpose of this study was to determine retinal hemoglobin oxygen saturation (SO 2 ) in patients with diabetic retinopathy (DR) using retinal oximetry (RO) and to correlate the degree of retinal ischemia using intravenous fluorescein angiography (IVFA).METHODS. This is a single-center cross-sectional cohort study. Twenty-seven controls and 60 adult patients with diabetes mellitus (16 without DR and 44 with DR) were enrolled. Patients were stratified according to DR severity. Using RO, SO 2 was measured in major retinal arterioles (SaO 2 ) and venules (SvO 2 ). Using IVFA, the percentage of retinal ischemia in 31 patients with DR was calculated and correlated with RO. RESULTS.Pairwise one-way analysis of variance (ANOVA) showed a significant increase in SaO 2 and SvO 2 in patients with proliferative DR (PDR) compared with controls (SaO 2 : PDR, 100 6 7% vs. controls, 91 6 4% [P ¼ 0.003]; SvO 2 : PDR, 66 6 11% vs. controls, 53 6 6% [P < 0.00001]). The percentage of retinal ischemia also increased with DR severity: ANOVA showed a significant difference in retinal ischemia between all categories of nonproliferative DR vs. PDR: 2.31 6 2% vs. 7.92 6 9% (P ¼ 0.017), respectively. Pearson two-tailed correlation showed significant correlation between SaO 2 and ischemia (R ¼ 0.467, P ¼ 0.011).CONCLUSIONS. Hemoglobin oxygen saturation of retinal arterioles and venules increases with DR severity; SaO 2 correlates with increasing ischemia measured by IVFA. Retinal oximetry may complement current imaging strategies to noninvasively augment the diagnosis and risk stratification of patients with diabetes.Keywords: retinal oximetry, diabetic retinopathy, fluorescein angiography I schemia plays a central role in the pathophysiology of diabetic retinopathy (DR). As ischemia increases, untreated DR generally progresses through four stages in an orderly fashion: mild nonproliferative DR (NPDR), moderate NPDR, severe NPDR, and proliferative DR (PDR). Intravenous fluorescein angiography (IVFA) is the gold standard to assess retinal ischemia and perfusion and is also helpful when determining treatment for DR. However, IVFA is relatively invasive as it requires the intravenous injection of contrast dye. Furthermore, IVFA provides only the anatomic state of retinal vessels and does not give any metabolic information, such as oxygenation.Recently, quantitative measurement of oxygen saturation (SO 2 ) has been possible using retinal oximetry (RO), a noninvasive imaging modality used to estimate hemoglobin oxygen saturation in retinal arterioles and venules. The technical aspects of RO have been previously described in the literature.1-3 Briefly, RO is based on similar principles as standard pulse oximetry, utilizing the light absorbance of oxyhemoglobin and deoxyhemoglobin at the carefully selected wavelengths of 570 and 600 nm. Studies have shown that the retinal oximeter produces repeatable and reliable measurements when detecting differences in SO 2 levels in controls, as well as in patients with retinal pathology. [3][4][5]...

OCTA reveals that eyes with Best disease have abnormal FAZ, patchy vascularity loss in the superficial and deep layers of the retina and capillary dropout with a hyporeflective centre in CC layer. Further, OCTA is superior to FA in measuring CNV.

RPE damage on FAF appears to be significantly larger than CC layer vessel loss on OCTA, which suggests that RPE damage might precede that of CC.

Central serous chorioretinopathy (CSCR) is a common chorioretinal disease characterized by serous retinal detachment that most commonly involves the macular region. Although the natural history of the acute form shows a self-limiting course, a significant number of patients suffer from recurrent episodes leading to chronic disease, often leaving patients with residual visual impairment. Visual morbidity is often worsened by a delay in the diagnosis due to the incorrect understanding of the particular biomarkers of the disease. The aim of this review is to provide clinical understanding of the biomarkers of CSCR with an emphasis on the most recent findings in patient demographics, risk factors, clinical imaging findings, and management options. Patients with these biomarkers, age 30–44 years, male gender, increased stress levels, hypercortisolism (endogenous and exogenous exposures), sleep disturbance, pregnancy, and genetic predisposition have increased susceptibility to CSCR. Also, biomarkers on optical coherence tomography (OCT) such as choroidal thickness (CT) and choroidal vascularity index (CVI) showed good diagnostic and prognostic significance in the management of CSCR. There are nonspecific features of CSCR on OCT and OCT angiography such as choroidal neovascularization, photoreceptor alteration/cone density loss, and flat irregular pigment epithelium detachment. We described rare complications of CSCR such as cystoid macular edema (CME) and cystoid macular degeneration (CMD). Patients with CME recovered some vision when treated with anti-vascular endothelial growth factors (anti-VEGFs). Patients with CMD had irreversible macular damage even after treatment with anti-VEGFs.

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