Changes in retinal oxygen saturation, choroidal thickness, and retinal nerve fibre layer

Objective To investigate the changes of retinal oxygen saturation (Sat O 2 ) concentrations, choroidal thickness (CT), and retinal nerve fibre layer (RNFL) in eyes with trabeculectomy-required acute primary angle closure (APAC). Design Prospective, longitudinal study. Participants Twenty-three eyes with trabeculectomy-required APAC were recruited. Methods Retinal oximetry was performed at postoperative day one and again at approximately 1 month. CT and the RNFL were tested on the same day. A paired t test and Pearson correlation were used for analysis. Results Mean Sat O 2 increased in retinal arterioles from 88.74% ± 14.36% at postoperative day 1 to 96.61% ± 18.42% at 1 month ( p = 0.049). The mean diameter of the arterioles was statistically different between postoperative day 1 and 1 month ( p = 0.044), as was the mean diameter of the venules ( p = 0.027). APAC eyes at postoperative 1 month had a thinner mean CT, compared with day 1 ( p = 0.002). No significant difference was found in the RNFL between postoperative day 1 and 1 month ( p > 0.05). The Sat O 2 in retinal arterioles correlated with the mean diameter of the arterioles at postoperative day 1 ( r = –0.482, p = 0.020) and at 1 month ( r = –0.463, p = 0.026). No significant correlation was found between retinal Sat O 2 and other parameters. Conclusions Increased Sat O 2 in retinal arterioles, changed vessel diameter, and thinner CT from postoperative day 1 to 1 month suggest gradual recovery from APAC. However, the different pathophysiologies for APAC still need further study to prove.