Abstract

Enhanced S cone syndrome (ESCS) is a retinal degenerative disease associated with nightblindness and hypersensitivity of the short-wavelength-sensitive (S) cone system.^1-3 Patients with ESCS have characteristic electroretinograms (ERG) with a large negative component (a-wave) in the presence of a background field. The a-wave can be as large or larger than the normal dark-adapted rod a-wave.^1-7 Recent studies have demonstrated that these a-wave responses are mediated almost entirely by receptors with S-cone pigment.^1-3,8,9 The syndrome gets its name from these large a-wave responses and psychophysical evidence of hypersensitivity of the S-cone system.²

© 1995 Optical Society of America