Heterochromia after pediatric cataract surgery

Purpose: Changes in iris color have been noted anecdotally after cataract s urgery in inf ants, but they have not been studied systematically. The mech anism for these iris color changes has not previously been reported in the biomedical literature. Methods: Photographs were taken of both eyes of 15 c hildren and 11 rhesus monkeys who had undergone unilateral cataract surgery . Masked examiners reviewed the photographs and compared the iris color of the eyes that were operated on with the eyes that were not operated on. Bet ween 4 and 6 weeks postoperatively, the level of prostaglandin F-2 alpha in the aqueous humor (n = 4) and vitreous humor (n = 2) was measured in both the operated and nonoperated eyes of 4 monkeys that had undergone a neonata l lensectomy during the first 5 days of life. Results: Thirteen of 15 child ren had a darker iris color in the operated eye in relation to the nonopera ted (control) eye. Four of 11 monkeys had a uniformly darker iris in the op erated eye; the other 7 monkeys had regional darkening or patches of darker iris in the eye that was operated on. The prostaglandin F-2 alpha levels i n neonatal monkeys were higher in the aqueous humor and in the vitreous hum or of the operated eye in relation to the nonoperated eye. Conclusion: In s ome children, cataract surgery is associated with a darkening of the iris c olor in the operated eye. We speculate that this darkening results from an exuberant prostaglandin release stimulated by the cataract surgery and may occur through the same or a similar mechanism by which latanoprost causes t he darkening of iris color.