Iridoschisis: High frequency ultrasound imaging. Evidence for a genetic defect?

Aims - To elucidate changes in the anatomy of the anterior chamber associated with iridoschisis, a rare form of iris atrophy, and their potential contribution to angle closure glaucoma. Methods - Both eyes of a 71-year-old woman with bilateral iridoschisis and fibrous dysplasia and her asymptomatic 50-year-old daughter were scanned with a very high frequency (50 MHz) ultrasound system. Results - The symptomatic patient exhibited diffuse changes in the iris stoma with an intact posterior iris pigmented layer in both eyes. These changes were clinically compatible with the lack of iris transillumination defects. Additionally, iris bowing with a resultant narrowing of the angle occurred. The asymptomatic daughter showed discrete, but less severe iris stromal changes. Conclusion - This is the first detailed study of high frequency ultrasonic imaging of the iris in iridoschisis. The observed structural changes suggest angle narrowing by forward bowing of the anterior iris stroma may be a mechanism of IOP elevation in this condition. The ultrasonic detection ofiris changes in the asymptomatic daughter of the symptomatic patient and the association of iridoschisis with fibrous dysplasia suggest a possible genetic component in the pathogenesis of this condition.