Choroidal microvascular dropout as a biomarker of glaucoma progression in patients with diabetes mellitus
Purpose. To study the occurrence, features of the development of choroidal microvascular dropout (CMvD) as a possible marker of the severity of the glaucoma process and to assess the impact of diabetes mellitus (DM) on the progression of these changes. Material and methods. The study included 258 eyes (258 patients), which were divided into groups: 1st - 58 patients (58 eyes) with stage I POAG and DM; 2nd - 50 patients (50 eyes) with stage I POAG; 3rd - 50 patients (50 eyes) with stage III POAG and DM; 4th - 50 patients (50 eyes) with stage III POAG; 5th - 50 patients (50 eyes) with DM. The observation period lasted 24 months. The occurrence and dynamics of the development of CMvD, their relationship with structural and functional indicators of the optic disc in the course of observation were evaluated in patients with POAG and DM. Results. CMvD was detected in stage I POAG in 17 eyes (34%), in patients with DM - in 27 eyes (54%), in the combined course of stage I POAG and DM - in 46 eyes (79.31%), in patients with stage III glaucoma - in 100% of cases. In patients with stage III glaucoma, the CMvD area indicators exceeded the values in other groups and practically did not differ regardless the presence of DM (0.59±0.13 mm2, p=0.005) and its absence (0.57±0.14 mm2, p=0.005). In the first year of follow-up, the increase in the area size of microvascular disorders in patients with POAG I was 5.88%, in comorbid patients - 3.84%, but by the end of the follow-up it increased by 19.23%, and in the group of patients with a high rate of progression - by 31.25%. Strong reliable correlations of CMvD with mean deviation (r=0.89) were revealed, as well as moderate correlations - with structural indicators of the optic disc (r=0.59) and with hemodynamic indicators (r=0.54 and r=0.52). Conclusion. Development of CMvD is both a result of glaucomatous damage to the optic nerve and a consequence of a disruption of its hemodynamics at the level of the deep capillary plexus. The results of the study demonstrate the adverse effect of DM on the course of glaucoma, which determines the initiation of microvascular disorders that aggravate the severity of the glaucoma process and the rate of its progression.