OCT angiography of the posterior pole of the eye in conditions of hypotony after glaucoma surgery

Relevance Postoperative hypotension is a condition in which the intraocular pressure level is below the average normal values ​​(below 8 mm Hg), achieved through surgical treatment of glaucoma [1, 2]. Low pressure does not always lead to complications in the form of choroidal detachment and decreased visual acuity. The glaucoma process in such eyes is most likely almost stopped, and changes in blood flow can create conditions for more intensive blood supply to the retinal ganglion cells [3]. Objective To study the effect of postoperative hypotension on blood flow parameters in the posterior pole of the eye. Material and methods The study included 10 patients (10 eyes) with operated primary open-angle glaucoma, who had hypotension without concomitant complications for more than 6 months after surgery. During the six-month dynamic observation (with an interval of 3 months) after the operation, the patients underwent a standard ophthalmological examination, as well as special instrumental studies, including ultrasound of the operated eye and optical coherence tomography in angio mode (OCTA) of the optic nerve head and macular zone of the retina. Results According to OCTA, with prolonged hypotension, the overall blood flow indicator in percent (Total) changed as follows: in the optic nerve head area, the median was 4 (3; 6), in the superficial plexus of the macular zone 2 (2; 6), in the deep plexus 3 (2; 4). A small spread of values ​​is probably associated with a small sample and a short observation period. Conclusion Postoperative hypotension affects the blood flow indicators of the posterior pole of the eye. Key words: glaucoma; intraocular pressure; hypotension; OCT angiography