Iris microhemangiomas.

Iris microhemangiomas (IM) are benign proliferations of small, twisted blood vessels along the pupillary margin. They are usually bilateral and appear to be developmental in nature. IMs most commonly occur in patients with myotonic dystrophy and adult-onset diabetes mellitus, but have also been associated with respiratory disease, congential heart disease, and central retinal vein occlusion. Additionally, they may be found in individuals without obvious ocular or systemic abnormality. The etiology remains obscure. In this report, illustrative cases are followed by a brief discussion outlining typical clinical manifestations, etiological considerations, and possible implications.