Purpose
To analyze oxygen saturation in retinal vessels of patients with geographic atrophy (GA) due to age-related macular degeneration (AMD).
Methods
Retinal oximetry was performed in retinal vessels with Oxymap T1 oximeter (Oxymap ehf., Reykjavik, Iceland), which is based on a fundus camera using spectrophotometric oxygen measurement. Two images with a wavelength of 600 nm (oxygen saturation sensitivity value) and 570 nm (oxygen-insensitive value) of the same fundus area were taken. 14 eyes of 10 patients with GA due to AMD were compared to 20 age-matched eyes of 10 patients with incipient AMD (Drusen only) or 20 eyes of 10 patients with no retinal diseases present (healthy controls). For each study participant the retinal arterial oxygen saturation, venous oxygen saturation and the arteriovenous (A-V) difference combined with the measurement of each vessel diameter were analyzed within a ring area concentric to the optic disc. Data are presented as mean ± standard deviation and significance calculated based on a paired t-test (p<0.05 considered statistically significant).
Results
The age of study participants ranged between 70 and 79 years, with no statistical significance observed between study cohorts. Mean oxygen saturation values of retinal venous vessels in patients with GA were significantly higher compared to healthy subjects or patients with incipient AMD (p=0.012; p=0.019). No statistical significance could be observed in the oxygen saturation of arterial vessels between the 3 study groups. Similarly, A-V difference showed no statistical significance between the study cohorts. The mean retinal vessel diameter of both venules and arterioles were not significantly different in patients with GA compared to eyes with incipient AMD or healthy controls.
Conclusions
Our results show that the oxygen saturation in retinal vessels was increased in venules of eyes with GA compared to healthy controls or eyes with early AMD. These data suggest that the oxygen delivery/consumption from the retinal circulation to the inner retina may be impaired in patients with GA.
Keywords: 412 age-related macular degeneration •
635 oxygen