ObjectiveTo observe the incidence of diabetic iridopathy and optic disc neovascularization in the contralateral eyes of proliferative diabetic retinopathy (PDR) with proliferative diabetic iridopathy (PDI). MethodsA retrospective case-control study. From February 2014 to May 2020, 72 eyes of 36 patients with PDR and PDI who underwent iris fluorescein angiography (IFA) combined with fluorescein fundus angiography (FFA) at the Henan Eye Institute were enrolled in the study. Among them, there were 34 eyes in 17 males and 38 eyes in 19 females; the average age was 62.3±4.7 years. All patients underwent best corrected visual acuity (BCVA), intraocular pressure, IFA combined with FFA examination. The BCVA examination was performed using the international standard visual acuity chart, which was converted into logarithm of the minimum angle of resolution BCVA for statistic analysis. According to PDI staging, patients were divided into early rubeosis iridis (RI) group and neovascular glaucoma (NVG) group, with 28 and 8 cases respectively. Compared with NVG group, RI group had better BCVA and intraocular pressure, and the difference was statistically significant (t=6.433, 10.619; P=0.000, 0.011). The incidence of PDI and the incidence of binocular optic disc neovascularization in the two groups were compared, and Fisher's exact probability method was used for comparison. ResultsThe results of the IFA examination showed that in the RI group, the pupil border and the iris surface of the iris of the affected eyes had strong neovascular bud-like or patchy fluorescence; the pupil border and the middle of the iris of the patients in the NVG stage had strong neovascular cluster-like fluorescence. Among the contralateral eyes in the RI group, 6 eyes (21.4%, 6/28) were with PDI (stage RI), 21 eyes (75.0%, 21/28) were with non-PDI (NPDI), and 1 eye (1/ 28, 3.6%) were absence of diabetic iris disease. Among the contralateral eyes in the NVG group, there were 5 eyes with PDI (62.5%, 5/8), including 4 eyes with RI stage, 1 eye with NVG stage (12.5%, 1/8); 3 eyes with NPDI. The image of IFA in patients with NPDI early showed as punctate fluorescence in the local small blood vessels of the iris itself. The incidence of PDI in the contralateral eye of the RI group was lower than that of the NVG group, and the difference was statistically significant (P=0.040). The results of FFA examination showed that 9 (32.1%, 9/28) and 8 (28.6%, 8/28) eyes of the affected eye and the contralateral eye in the RI group were combined with optic disc neovascularization. In NVG group, there were seperately 6 eyes (75.0%, 6/8) in the affected eyes and the contralateral eyes with optic disc neovascularization. The differences in the incidence of optic disc neovascularization between the two groups of the affected eyes and the contralateral eye were statistically significant (P=0.046, 0.040). ConclusionThe incidence of PDI and optic disc neovascularization in the contralateral eye of PDR and PDI, RI is lower than that of NVG.