Poor night vision and pigmentary retinopathy are hallmarks of retinitis pigmentosa, but variations in the type of pigmentation and in the characteristics of the electroretinogram (ERG) can point to other diagnoses. The case below (enhanced S cone syndrome) is a good example of this, and demonstrates the diagnostic importance of clinical electrophysiology.
Keywords ERG - Night blindness - Enhanced S cone syndrome - Retinitis pigmentosa - Goldmann-Favre syndrome