Predicting the effectiveness of anti-glaucoma surgery based on an estimate of the volume of the filtering bleb

Relevance Glaucoma is one of the main causes of irreversible low vision and blindness. The goal of glaucoma treatment is to reduce and maintain a safe level of intraocular pressure (IOP). The most effective in terms of achieving a safe level of IOP is a surgical approach [1, 2]. Evaluation of the filtration pad (FP) condition is one of the most important evaluation criteria that allows indirectly judging the degree of compensation of the process and determines the tactics of further patient management. Currently available classifications of filtration pads do not allow predicting the effectiveness of surgical treatment of glaucoma [3-5]. Objective To study the possibility of optical coherence tomography (OCT) as a tool for predicting the hypotensive effectiveness of antiglaucoma surgery based on the parameters of the filtration pad. Material and methods The study included 15 patients (15 eyes) with uncompensated primary open-angle glaucoma, who underwent sinus trabeculectomy with basal iridectomy. A three-dimensional model of the formed AF was assessed and its volume was calculated using OCT on the 2nd and 7th days after surgery, after 1 and 3 months. Results By the end of the observation period, the AF volume in 3 patients was less than 5.7 mm3, which was associated with an unsuccessful outcome of the surgery and an increase in intraocular pressure (IOP) to 22.1 ± 3.2 mm Hg. To achieve target IOP values, these patients were prescribed a hypotensive regimen. In the remaining patients (12 people), the IOP level was up to 14 mm Hg throughout the entire observation period (on average 11.7 ± 2.3 mm Hg). The AF was diffuse, and its volume was more than 5.7 mm3. The obtained result of surgical treatment of glaucoma allowed leaving patients under dynamic observation without prescribing a hypotensive regimen. Conclusion The threshold value of the FP volume, determining the long-term effectiveness of antiglaucoma surgery, is 5.7 mm3. Keywords: glaucoma; antiglaucoma surgery; filtration cushion; excessive scarring