The goal of the study was to assess the role of concomitant somatic pathology and calculate the total comorbidity index of primary open-angle glaucoma (POAG) in different age groups. Material and Methods — The study included 624 patients (1199 eyes) with POAG aged 45 to 93 years. The control group included 161 people without glaucoma. Patients underwent a comprehensive ophthalmological examination. The Charlson comorbidity index (CI) was calculated, taking into account the concomitant somatic diseases and the age of the patients. Statistical processing of the obtained material was carried out using the IBM SPSS Statistics v.21 program with standard methods of descriptive statistics. Results — with an increase in the age of POAG patients, significant growth in the number of patients with hypertension, coronary heart disease, cerebrovascular accident, atherosclerosis, degenerative diseases of the nervous system, diabetes mellitus, respiratory diseases, musculoskeletal system, and other pathologies were observed. CI was increased in POAG patients with age: 3.02 times for the old age patients, 4.2 times for very old age subjects, compared with middle-aged patients (p<0.001), as well as 1.42 and 1.97 times, respectively, compared with the control group (p<0.001). Conclusion —In patients with POAG, the number of patients with hypertension, ischemic heart disease, cerebrovascular disorders, atherosclerosis, degenerative diseases of the nervous system, diabetes mellitus, respiratory diseases, musculoskeletal system disorders, and other pathologies increased significantly with age. The comorbidity index in POAG patients exhibited growth with age: 3.02 times in the old age group and 4.2 times in the group of very old age people vs. the group of middle-aged patients (p<0.001); and 1.42 and 1.97 times, respectively, vs. the control group (p<0.001).