The effect of autoimmune retinopathy on retinal vessel oxygen saturation

To study the retinal vessel oxygen saturation alterations in patients with autoimmune retinopathy (AIR) and patients with autoimmune retinopathy associated with retinitis pigmentosa (AIR-RP) in comparison with healthy controls and patients with isolated retinitis pigmentosa (RP).

Prospective, cross-sectional, and non-interventional study.

Retinal vessel oximetry (RO) was performed on a total of 139 eyes: six eyes suffering from AIR and four eyes with AIR-RP were compared to 59 healthy control eyes and to 70 eyes with RP.

A computer-based program of the retinal vessel analyser unit (IMEDOS Systems UG, Jena, Germany) was used to evaluate retinal vessel oxygen saturation. The mean oxygen saturation in the first and second branch retinal arterioles (A-SO₂) and venules (V-SO₂) were measured and their difference (A-V SO₂) was calculated. In addition, we measured the diameter of the retinal arterioles (D-A) and venules (D-V).

Oxygen metabolism is altered in patients with isolated AIR and AIR-RP.

Both, AIR and AIR-RP groups, differed from healthy controls showing significantly higher V-SO₂ values and significantly lower A-V SO₂ values (p < 0.025). In addition, the AIR-RP group could be differentiated from eyes suffering from isolated RP by means of significantly higher V-SO₂ values. Comparing retinal vessel diameters, both, the AIR and AIR-RP groups, presented with significant arterial (p = 0.05) and venular (p < 0.03) vessel attenuation than the healthy control group.

Based on our results, in analogy to patients suffering from RP, oxygen metabolism seems to be altered in AIR patients.