To monitor the influence of glaucoma on the changes caused by diabetes in the anterior ocular segment. Material and methods: Prospective, comparative clinical study, which included the patients with glaucoma and diabetes assessed at the Iasi "Sf. Spiridon" Hospital, "Euro Medi Center" Clinic and "Oftaprof" Clinic. The study included a number of 142 patients, divided into two groups: 67 patients with glaucoma and diabetes (study group) and 75 patients with diabetes mellitus (control group). Upon enrollment the patients were subjected to a complete assessment of their ophthalmologic and metabolic status. Monitored aspects: prevalence of lens changes, extent of ocular surface disease and identification of the changes in corneal biomechanical parameters in the patients with glaucoma and diabetes. Results: In both monitored groups, the cortical lens changes prevailed, both at the beginning and at the end of the study, with no statistically significant differences between groups (p>0.05). The risk of developing lens changes reaches 50% in the patients who have had diabetes for 20 years. In the patients in the study group, tear secretion was significantly lower at the end of the study (Schirmer's test values 11.61 vs. 10.67 mm, p=0.045). Tear film instability was present in 37.3% of the patients. Corneal hysteresis (CH) and corneal resistance fact or were significantly reduced in the group with glaucoma and diabetes, as compared to the group with diabetes (p=0.001). Conclusions: There is significant ocular surface disease in the patients with glaucoma and diabetes, as compared to those with diabetes alone. Glaucoma and the number of antiglaucoma drugs are associated with a significant reduction in tear secretion. The association of glaucoma resulted in the reduction in CH and corneal resistance factor in the patients with glaucoma and diabetes as compared to the healthy ones.