Sign Up for a Free Account

This is an image preview.
Start a Free Account
to view the full image.

  • Nearly 3,000 illustrations, including video clips of neurologic disorders.

  • Every article is reviewed by our esteemed Editorial Board for accuracy and currency.

  • Full spectrum of neurology in 1,200 comprehensive articles.

  • Listen to MedLink on the go with Audio versions of each article.

Retinitis pigmentosa (ERG)

The EGR is usually affected profoundly and early in the retinitis pigmentosa disease process, with both scotopic (rod) and photopic (cone) function being affected. Here, a normal ERG is contrasted to a retinitis pigmentosa patient ERG. The top 3 records are from a normal patient and represent from the top down: (1) scotopic and photopic function; (2) isolated photopic function; and (3) isolated scotopic function. The bottom record is from a retinitis pigmentosa patient and reflects an absence of scotopic function. (Contributed by Dr. James Walters.)

Associated Disorders

  • Bassen-Kornzweig disease
  • Cushing syndrome
  • Kearns-Sayre syndrome
  • Lawrence-Moon-Biedl syndrome
  • Mitochondrial encephalopathy with lactic acidosis and stroke-like episodes (MELAS)
  • Ocular paraneoplastic syndromes
  • Refsum disease
  • Usher syndrome
  • gastroesophageal reflux disease
  • posterior vitreous detachment
  • retinal detachment
  • systemic arterial hypertension
  • systemic lupus erythematosus