Retinal vascular impairment in patients newly diagnosed with obstructive sleep apnea syndrome

Background: To evaluate retinal morphological and vascular parameters in patients recently diagnosed with obstructive sleep apnea syndrome (OSAS) and determine the correlation between retinal vascular density and the severity of OSAS.Methods: We performed a retrospective study on the retinal vasculature of patients with OSAS and age-match healthy controls. OSAS was confirmed by full-night cardiorespiratory polygraphy. Patients were divided into three groups according to disease severity given by apnea-hypopnea index (AHI) i.e., mild, moderate or severe. Retinal thicknesses and vascular density were compared between groups, for both the macula and optic disc. Correlation between vascular density and clinical features were also assessed.Results: The study included 30 eyes of patients with OSAS and 12 controls. No differences were found regarding retinal thickness in both the macula and the optic disc between OSAS patients and controls. In contrast significant differences were found in the peripapillary vessel density between groups versus control patients. The greatest difference being between severe OSAS and controls (49.4% ± 2.1 versus 40.4% ± 4.2 respectively, p=0.01). Peripapillary vessel density was found to significantly and negatively correlate with AHI (p=0.02; r= -0.74) and directly correlate with the lowest percutaneous oxygen saturation (p=0.02; r= 0.58).Conclusions: This study indicates that OSAS is associated with retinal microvasculature impairment, that seems to mainly affect the optic disc. This suggests that microvascular damage increases with the increasing severity of OSAS. As such prospective trials are needed to clarify if this vascular peripapillary damage precedes glaucomatous optic neuropathy in OSAS patients.