APR 16, 2010
In this prospective, cross-sectional study, pattern electroretinography (PERG) from standard (12°×16°) and larger (24°×32°) stimulus fields and spectral-domain optical coherence tomography were used to evaluate macular function in 18 patients with genetically confirmed Stargardt disease and 18 control subjects.
Eighty-six percent of eyes showed a PERG P50 (ganglion cells plus significant contributions from retinal neurons distal to ganglion cells) response to the larger stimulus field, with a mean amplitude of 2.3 μV, compared to 22 percent and 1.0 μV for the standard stimulus field. However, the specificity and sensitivity of PERG to the standard stimulus field were greater than for the larger field. For both PERG P50 and N95 (retinal ganglion cell function only), the differences in their amplitudes between the standard and larger stimulus fields correlated significantly with visual acuity and tomography parameters.
The authors concluded that the higher sensitivity and specificity of PERG for the standard stimulus field allows detection of early maculopathy in patients with Stargardt, whereas PERG with the larger stimulus field provides a better evaluation of the degree of retinal involvement and quantification of progression of photoreceptor damage in patients with Stargardt.