Clinical implications of retinal oximetry in retinal vein occlusion: a review

Abstract

To review retinal vein occlusion (RVO) and its relationship with retinal oxygen saturation via automated retinal oximetry in eyes with RVO. Methods.A literature review was performed in PubMed and Medline until October 2021 utilizing specific keywords and cross-matched reference lists. Results.This review found RVO to be associated with risk factors including age, hypertension, cardiovascular and metabolic conditions, male gender, and glaucoma. These may be attributed to a breakdown of regulatory processes in the retina. Retinal venous oxygen saturation (SvO 2 ) and arteriovenous difference in eyes with central RVO have been found to be reduced and elevated, respectively. The literature indicates variable and contradictory findings in regard to branch RVO and retinal oxygenation. Additionally, ischaemic eyes have been found to have elevated retinal arterial oxygen saturation; however, the literature reports variable results regarding SvO 2 levels. Medications have been suggested to increase SvO 2 in RVO eyes, which may represent an important mechanism for disease management. Ranibizumab is currently the most studied drug for retinal oxygenation in RVO and has been suggested to increase SvO 2 in RVO eyes. In comparison, dexamethasone was found to decrease SvO 2 . Conclusion.The current literature on retinal oxygenation in ischaemic subtypes of RVO and in drug therapies is minimal, and further work is required to expand upon our understanding of how ischaemia and drugs influence retinal oxygenation and clinical outcomes.

Pretreatment ocular blood flow and retinal oxygen metabolism in the acute uveitic phase is associated with final outcome in Vogt‐Koyanagi‐Harada disease

“…This is an indication of a clear correlation between metabolic and structural changes induced by inflammation. Our findings suggest that the retina is more hypoxic in the late presentation group and in the eyes that subsequently developed SGF (Belamkar et al., 2022; Eliasdottir et al., 2015; Jeppesen & Bek, 2017; Krejberg Jeppesen et al., 2021; Sinova et al., 2018; Stefansson et al., 2019) to result in increased extraction of oxygen as a consequence of prolonged inflammation‐related blood flow impairment in the acute uveitic phase of VKH disease. We hypothesise that inflammation‐induced blood flow impairment and exudative retinal detachment result in a retinal hypoxic condition, particularly in the late presentation group and among eyes that subsequently developed SGF.…”

“…A consequent decrease in blood flow to the retina can lead to hypoxia. These studies reported lower oxygen saturation in retinal venules and a higher arteriovenous saturation difference in eyes with central retinal vein occlusion compared to their fellow eyes (Belamkar et al., 2022; Eliasdottir et al., 2015; Jeppesen & Bek, 2017; Krejberg Jeppesen et al., 2021; Sinova et al., 2018; Stefansson et al., 2019). In patients with central retinal vein occlusion, a significant negative correlation was found between the ischaemic index and vein saturation and a significant positive correlation between the ischaemic index and the arteriovenous saturation difference (Sinova et al., 2018).…”

m6A modifications of circular RNAs in ischemia-induced retinal neovascularization

“…As the shared pathogenesis of proliferative diabetic retinopathy (PDR), retinopathy of prematurity (ROP), and other retinal vasculopathies, ischemiainduced pathological retinal neovascularization is a common cause of irreversible blindness globally in various age groups [1][2][3]. Therefore, effective intervention has become crucial to reducing the severe vision loss caused by retinal neovascularization.…”