The effect of acute zonular occult outer retinopathy on retinal vessel oxygen saturation

Purpose: To measure the retinal vessel oxygen saturation alteration with retinal oximetry (RO) in patients with acute zonular occult outer retinopathy (AZOOR) and compare these findings with retinitis pigmentosa (RP) and controls. Methods : Prospective observational study examining 189 eyes of 98 patients: 12 eyes of 6 AZOOR patients (1♂5♀; 48.5 ± 19.2 years (mean ± SD) were compared to 77 eyes from 39 patients with RP (15♀ 24♂; 45.6 ± 14.7 years) and 100 eyes from 53 controls (31♀ 22♂; 40.2 ± 13.4 years). Main outcome measures were the mean arterial (A-SO ₂ ; %), venular (V-SO ₂ ; %) oxygen saturation, as well as their difference (A-V SO ₂ ; %) measured with the oxygen saturation tool of the Retinal Vessel Analyzer (IMEDOS Systems UG, Germany). Statistical analysis was performed and included in the linear mixed-effects models analysis calculated with SPSS®. Results : Eyes affected by AZOOR differed significantly from both RP and control eyes in terms of retinal oxygen metabolic parameters. Compared to controls, AZOOR eyes showed significantly higher A-SO₂ and V-SO₂ values (p = 0.031 and p = 0.044, respectively), while V-SO₂ was significantly lower in AZOOR compared to RP eyes (p = 0.035). A–V SO₂, which reflects retinal oxygen consumption, was significantly reduced only in RP eyes, but not in AZOOR eyes, when compared to controls. Conclusion : Assessments of retinal oxygen metabolism might contribute to a correct diagnosis and a better understanding of the pathogenesis of AZOOR and RP.