Online Photo Diagnosis

Online Photo Diagnosis

June 2012 Online Photo Diagnosis

By William Townsend, OD, FAAO

The individual in this image presented with iris atrophy, a relatively uncommon disorder that can result from a variety of conditions. Iris atrophy may affect the anterior surface, stroma, or pigment endothelium of the iris, or some combination of the three. Atrophy of the iris pigment epithelium results from pigmentary glaucoma, from epithelium rubbing on the anterior surface of the crystalline lens or from a posterior chamber intraocular lens. This is often visualized as iris transillumination defects.

Stromal atrophy results in thinning of the iris and loss of the crypts. As shown in this image, there is often loss of anterior layer with depigmentation.

Iris atrophy may result from genetic errors such as congenital dominant iris atrophy, Axenfeld-Reiger anomaly/syndrome, and age-related iris atrophy. Inflammatory conditions associated with uveitis (chronic iridocyclitis, Herpes zoster, Herpes simplex, tuberculosis, and syphilis) are potential causes for iris atrophy. Iridocorneoendothelial syndromes, i.e. Chandler syndrome, essential iris atrophy, and iris-nevus syndrome, are also uncommon causes for iris atrophy.

Conditions that lead to ischemia of the anterior segment may cause iris atrophy. Examples include angle closure glaucoma, cavernous sinus fistula, anterior segment ischemia syndrome, and carotid artery occlusion. All forms of glaucoma have the potential to cause some degree of iris atrophy. Age-related iris atrophy is considered a normal part of the aging process and varies widely in severity.

The diagnosis of iris atrophy is based on case history and clinical examination. External examination frequently reveals generalized thinning of the iris stroma, compressing of iris architecture and loss of crypts. The sphincter muscle is more easily visualized, and the red reflex may be seen through irregular areas of iris atrophy.

In this individual's case, the iris atrophy occurred secondary to laser treatment for retinal disease. The laser beam inadvertently struck the iris near the pupil margin and triggered the development of areas of atrophy. The patient's history provided the vital information that allowed us to identify the causative factors in the development of iris changes.

There is no specific treatment for iris atrophy. Because it may be associated with glaucoma or corneal changes, especially edema, therapy is focused on managing these co-morbidities.