Purpose: To study the spontaneous progression from iris neovasculariza
tion to neovascular glaucoma, factors that determine how long it takes
and the efficacy of therapy, we studied 81 eyes belonging to 67 diabe
tic patients. Methods: The eyes mere divided into three groups: contro
l group (29 eyes, 26 patients), photocoagulation group (37 eyes, 30 pa
tients) and cryotherapy group (15 eyes, 11 patients). The controls wer
e observed for at least 12 months, and the treated group over at least
the following 3 months. Results: At the end of the follow-up period 1
2 of the 29 control group eyes (41.4%) had developed neovascular glauc
oma and 6 (20.5%) increased neovascularization. Seven eyes (58%) that
developed glaucoma did so within 3 months. There was no significant di
fference between the laser therapy (improvement: 84%) and cryotherapy
group (80.5%). Conclusions: At the end of the 12-month follow-up perio
d progression from iris neovascularization to neovascular glaucoma is
very frequent. There was no difference between laser therapy and cryot
herapy.