Myotonic dystrophy may be associated with ciliary body detachment

Ophthalmology. 2011;118(2):260-264.

Ciliary body detachment and low IOP in patients who have not undergone recent ocular surgery or trauma suggest a diagnosis of myotonic dystrophy, a study showed.

"In a previously published study, we found this hypotony to be real and unrelated to different corneal biomechanical properties or endothelium abnormalities," the study authors said. "Although it has been suggested that the hypotony in [myotonic dystrophy type 1] could be related to increased outflow facility or decreased aqueous secretion, the pathophysiologic mechanism responsible for low IOP remains unclear."

Myotonic dystrophy type 1 is a muscular disorder characterized by myotonia and weakness. Ocular abnormalities associated with myotonic dystrophy include cataract, ptosis, exposure keratitis, pigmentary abnormalities and abnormal dark adaptation. Incidents of low IOP have also been reported.

The prospective study included 102 eyes of 51 patients with myotonic dystrophy type 1. Mean patient age was 37.1 years. A comparator group comprised 44 eyes of 22 healthy subjects. Mean patient age was 40.6 years.

Patients underwent IOP measurement, central corneal thickness measurement and ultrasound biomicroscopy to detect ciliary body detachment.

Mean IOP was 10.9 mm Hg in patients with myotonic dystrophy and 15.4 mm Hg in the control group. The difference was statistically significant (P < .01).

Mean central corneal thickness was 574.4 µm in eyes with myotonic dystrophy and 557.8 µm in control eyes. The difference was also statistically significant (P = .02).

All patients with myotonic dystrophy and no control subjects had ciliary body detachment, the authors reported.