[A new clinical entity: ascending solar iris degeneration. Report of 284 cases].

The observation in a certain number of subjects of an atypical iris depigmentation led us to study this phenomenon. Therefore, the authors engaged in a prospective study of 398 subjects (100 cases in the city of Marrakesh, and 298 in the city of Dakhla). The geography, clinical signs and environmental factors were studied. Depigmentation was observed in 55% of the population of Marrakesh and 77% of the population of Dakhla. It is bilateral, symmetric, very progressive, always begins in the inferior one-third of the iris, and always spares the superior iris covered by the eyelid. By the time the depigmentation reaches the middle one-third, the inferior one-third also begins to demonstrate stromal atrophy: (26 cases). Of the 45 subjects with normal iris pigmentation, 31 cases spend more than 8 hours per day in the shade, and 26 cases constantly use some means of solar protection (sunglasses, caps, "Taraza", "Feroual"). Thus, this acquired iris depigmentation of an ascending nature, accompanied by an advanced stage involving primarily inferior iris atrophy, appears to be closely associated with exposure to the sun. Ascending solar iris degeneration, if we may refer to it as such, is a clinical entity never before reported in the literature. Now that we are faced with this new condition, numerous questions arise, to which future research must respond. Are there other factors in addition to sun exposure, which may lead to the depigmentation? Does this condition lead to further ocular pathology (due to the depigmentation and stromal atrophy)? Must solar protection be prescribed systematically for anyone at risk?