Pigmentary retinopathy associated with neuromuscular pathology is present in a variety of disorders (see Table 14-1). ERG abnormalities found in these neurologic disorders confirm the presence of retinopathy but are not diagnostic for any one disorder.
Although Duchenne muscular dystrophy does not cause a pigmentary retinopathy, it deserves mention because the ERG signal shows a negative waveform similar to that found in patients with congenital stationary night blindness (CSNB)—specifically, a normal a-wave but a reduced b-wave (see Chapters 3 and 12). This ERG response suggests a defective “on-response” pathway, but patients with this disorder do not have night blindness. Interestingly, Duchenne muscular dystrophy is caused by mutations in the gene for dystrophin, a protein that is abundant in muscle but also found in neural synaptic regions and in the retina.
Barboni MT, Nagy BV, de Araújo Moura AL, et al. ON and OFF electroretinography and contrast sensitivity in Duchenne muscular dystrophy. Invest Ophthalmol Vis Sci. 2013;54(5):3195–3204.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.