Ocular findings in myotonic dystrophy

Thirty-three patients (20 female and 13 male patients aged 13 to 52 years) with myotonic dystrophy (MyD) were studied. Ophthalmologic examination included tonography, electroretinography (ERG), and fluorescein angiography. Thirty patients had bilateral cataracts of the subcapsular type, two patients had aphakia in both eyes, and one patient had clear lenses. Hypotonia (intraocular pressure, less than or equal to 10 mm Hg) was a common finding in 19 of 66 eyes. The mean IOP was 11.8 mm Hg for the whole series and the mean outflow facility was c = 0.34 cu mm/min. Focal signs of retinouveal affection were present in nine patients. Clinically, they appeared as acquired lesions affecting the retina, pigment epithelium, and choroid. One patient was found to have an outburnt panuveitis. The ERG was normal in 11 patients, subnormal in five patients, and isoelectric in four patients. An extinguished ERG did not correlate to clinical findings of known hereditary retinal or choroidal dystrophies. The ophthalmologic findings may be explained by a primary defect related to the cell membrane.