Background: Spherophakia is an uncommon diagnosis. This is the first case report of spherophakia evaluated by ultrasound biomicroscopy.

Methods: Ultrasound biomicroscopy is a new diagnostic technique developed by one of the authors and provides images with microscopic resolution of the anterior segment. A patient with spherophakia was evaluated by ultrasound biomicroscopy (Zeiss-Humphrey, 50MHz) before and after YAG laser iridotomy.

Results: Ultrasound biomicroscopic assessment revealed a shallow anterior chamber, a very steep anterior lens curvature, iridolenticular contact, elongated zonules, and an increased distance between the lens equator and the ciliary processes. Angle closure glaucoma was due to a pupil block mechanism. The pupil block was relieved by YAG laser iridotomy.

Conclusions: Ultrasound biomicroscopy is a useful technique to confirm the diagnosis of spherophakia. The pupil block in spherophakia is relieved by YAG laser iridotomy.