A total of 52 patients were included in the investigation, 12 patients (23.08%) were diagnosed with iris neovascularization and 4 patients (7.69%) developed neovascular glaucoma. The patients without iris neovascularization were defined as Group I, those with iris neovascularization as Group II, and those with neovascular glaucoma as Group III. The diabetes mellitus period was significantly longer in Group II (10.88 ± 7.14 years) and in Group III (11.75 ± 8.61 years) than Group I (8.30 ± 5.25 years) (p-value 0.41, 0.032, respectively). The HbA1c level was 9.59 ± 2.23 in Group II and 9.27 ± 2.54 in Group I. There was no significant difference between the two groups (p = 0.721). However, HbA1c was significantly higher in Group III (11.55 ± 0.21) than Group I (p-value 0.048).