Low intraocular pressure resulting from ciliary body detachment in patients with myotonic dystrophy

PURPOSE: To investigate why myotonic dystrophy type 1 (DM1) patients have low intraocular pressure (IOP). DESIGN: Prospective, comparative case series. PARTICIPANTS: One hundred two eyes of 51 patients with DM1 (age range, 21-64 years) and 44 eyes of 22 healthy subjects of similar age (21-64 years). METHODS: All participants underwent IOP measurement with Goldmann applanation tonometry and an in vivo examination of the ciliary body with a 35-MHz high-resolution B-scan. The findings were compared between the 2 groups. In both groups, only patients with no history of ocular trauma or surgery were included. The differences were evaluated using the unpaired Student t test. MAIN OUTCOME MEASUREMENTS: Intraocular pressure, central corneal thickness (CCT), and echographic evidence of ciliary body detachment. RESULTS: The mean ± standard deviation (SD) IOP in patients with DM1 was 10.9 ± 3.1 mmHg and that in the control patients was 15.4 ± 2.2 mmHg, a difference that reached significance (P