Abstract
Abstract: :
Purpose: To examine the presence of heterochromia iridus (difference in iris color) in patients with glaucoma in Sturge-Weber Syndrome (SWS) and evaluate whether it may signal a significant risk for glaucoma. Methods: Retrospective review of all patients with SWS presenting to the Massachusetts Eye and Ear Infirmary between January 1974 and January 1999. Glaucoma was defined by the presence of glaucomatous optic neuropathy, visual field defects and elevated intraocular pressure. Heterochromia was defined clinically by observation of difference in iris color (ie., one blue eye and one brown eye) or in degree of color (one eye darker than the other) at the time of initial presentation. Results: Sixty-two consecutive patients were identified (mean follow-up 60 6.5 months). 22 patients (36%) had glaucoma and 9 (14.5%) had evidence of heterochromia as documented at initial presentation. Eight (13%) of patients with glaucoma also had heterochromia and in all of these patients (100%) the iris was darker on the affected (glaucomatous) eye. There was a statistically significant difference in the presence of heterochromia between those who had glaucoma and those who did not (p= 0.002, Fisher exact test). The estimated odds ratio for the development of glaucoma given the presence of heterochromia was 14.6 (95% confidence interval = 1.77-120.2) Conclusion: The presence of heterochromia (with darker iris on the affected side) may be a positive predictor of glaucoma in patients with SWS and should indicate close follow-up for development of glaucoma in these patients. The embryological origin of iris melanocytes from neural crest cells and their role in iris pigmentation may support the theory that abnormal induction or migration of neural crest cells may contribute to the pathogenesis of glaucoma in SWS.