ABSTRACT
Diffuse retinal pigmentary alteration is a feature in a number of distinct disorders ranging from retinal dystrophies to systemic metabolic disorders. In addition, congenital infections such as rubella and syphilis may also produce pigmentary retinopathy. The clinical applications and findings of electrophysiologic tests in pigmentary retinopathies are covered in this chapter with the following outline:
Retinitis pigmentosa (rod-cone dystrophy) Leber congenital amaurosis Usher syndrome Bardet-Biedl syndrome Refsum syndrome Abetalipoproteinemia
(Bassen-Kornzweig syndrome) Neuronal ceroid lipofuscinosis Kearns-Sayre syndrome-mitochondrial retinopathy Rubella retinopathy Syphilitic retinopathy
Enhanced S cone syndrome Goldmann-Favre syndrome Dominant late-onset retinal degeneration Cone-rod dystrophy Alstro¨m syndrome
RETINITIS PIGMENTOSA (ROD-CONE DYSTROPHY)
Retinitis pigmentosa (RP) refers to a large group of genetically heterogeneous disorders characterized by early rod photoreceptor dysfunction and progressive rod and cone dysfunction. The prominent retinal pigmentary changes, which occurs in most but not all patients with RP led Donders to use the term ‘‘retinita pigmentosa’’ in 1857. Pigmentary retinal degenerations associated with systemic findings such as Refsum syndrome, Bardet-Biedl syndrome, BassenKornsweig syndrome, and neuronal ceroid lipofuscinosis (Batten disease) have occasionally been clumped under the broad category of RP or secondary RP. However, to avoid confusion, ‘‘retinitis pigmentosa’’ is recommended to be reserved only for primary rod-cone photoreceptor dystrophies and not as a synonym for pigmentary retinal degeneration (1).
