Importance of electrophysiology in ophthalmogenetics.

The only macular heredodegeneration which can be diagnosed by electrophysiological tests is the dominant vitelliform degeneration of the macula, the ERG being normal and the EOG very pathologic. In the pre- or subclinical or polymorphous atrophic stages it is even the only possibility of making the diagnosis. Autosomal dominant pigmentary retinopathy can rather often be differentiated from autosomal or sex-linked recessive pigmentary retinopathy by the fact that there is still an ERG response and more particularly a cone response and that its progressive deterioration is observed, while in autosomal or sex-linked recessive pigmentary retinopathy the ERG is mostly extinguished. The gene carriers of autosomal and sex-linked recessive pigmentary retinopathy as well as of choroideremia cannot be detected by electrophysiological tests. The visual evoked cortical potential cannot predict an optic disorder and is not able to distinguish hereditary from nonhereditary diseases of the optic nerve.