Duchenne muscular dystrophy: negative scotopic bright-flash electroretinogram but not congenital stationary night blindness

Patients with Duchenne muscular dystrophy (DMD) have recently been reported to have an abnormal scotopic electroretinogram (ERG) showing weak rod-related responses along with a negative configuration of the bright-flash response, which has been described as being similar to the one in congenital stationary night blindness (CSNB). We compared qualitatively and quantitatively the ERGs of 6 subjects with DMD, 10 subjects with the complete form of CSNB (cCSNB), 13 subjects with the incomplete form of CSNB (iCSNB) and 1 subject with complex glycerol kinase deficiency (CGKD). The rod-related activity and the bright-flash responses were abnormal and similar in all four groups. The cone-related activity, however, was within normal limits only in the DMD group; the b-wave was subnormal in CGKD, truncated in cCSNB and nearly absent in iCSNB. The electrophysiologic signature in DMD clearly distinguishes the retinal function of these patients from any other retinal condition so far described.