This case study involves a diagnosis of arteriovenous (AV) malformations of the iris. Evaluation warranted dilation of the pupil, thorough retinal examination, and visualization of the posterior side of the iris. Because the abnormal iris vasculature may not be the primary site of the abnormality in question, careful examination of the conjunctival vasculature is also needed.
The patient did not recall being told of any iris abnormalities in the past, and her last eye exam was reportedly about 5 or 6 years prior.
The patient was dilated with 1% tropicamide and 2.5% phenylephrine. While the patient was dilating, I researched this finding by consulting my Atlas of Eye Disease and performing a search of the world’s peer-reviewed literature.
Posterior segment examination showed healthy and dry retinas with healthy and perfused optic nerves. The patient was phakic with a trace amount of nuclear sclerosis in each eye. A three-mirror contact lens was used to better visualize the peripheral retina to the ora serrata in the left eye, and no abnormalities were seen. By this method, the posterior aspect of the iris was unremarkable to the extent to which it was seen.
Spectral domain optical coherence tomography (OCT) studies of the left iris and angle showed no other corresponding abnormalities. As it approached the angle, the iris was flat on each side.
In addition, B-scan ultrasound was unremarkable. Anterior segment photography of the abnormality was saved in the patient’s record, and this will be repeated at a follow-up visit.
Related: Retinal detachment seals itself
Based on the clinical presentation and lack of associated abnormal findings, the patient was diagnosed with an arteriovenous (AV) malformation of the left iris. The exact origin of this malformation was frankly unclear, but the iris was the only tissue with which it was in overt correspondence. AV malformations of the iris appear to be relatively benign findings, with the affected blood vessels exhibiting essentially normal function.1 There are also no apparent systemic associations.1
The patient was advised to call immediately if she experienced a sudden loss of vision and/or eye pain, which could be a sign of a hemorrhage into the anterior chamber—although the risk for such is likely very low. She was invited to return in 4 to 6 months for a follow-up examination and will be examined annually after that if all findings are stable.
Evaluation of such an abnormality of the iris warrants dilation of the pupil, thorough retinal examination, and visualization of the posterior side of the iris to check for related findings to include a malignancy of the iris or adjacent tissue.
A careful examination of the conjunctival vasculature is also warranted, in keeping with the notion that the abnormal iris vasculature may not be the primary site of the abnormality in question.
More by Dr. Casella: Coats’ disease: A case study of a 4-year old boy
1. Shields JA, Streicher TF, Spirkova JH, Stubna M, Shields CL. Arteriovenous malformation of the iris in 14 cases. Arch Ophthalmol. 2006 Mar;124(3):370-5.