Aims: To investigate the importance of a larger stimulus field for pattern electroretinography (PERG) in evaluating macular function in Stargardt disease, and to determine the relationship between PERG and spectral-domain optical coherence tomography (SD-OCT).
Methods: In this prospective cross-sectional study, PERG from standard (12 degrees x 16 degrees ) and larger (24 degrees x 32 degrees ) stimulus fields and SD-OCT were recorded in 18 patients with genetically confirmed Stargardt disease, and in 18 control subjects.
Results: A PERG P50 response to the larger stimulus field was detectable in 86% of eyes, with a mean P50 amplitude of 2.3 microV, compared with 22% and 1.0 muV for the standard stimulus field. The specificity and sensitivity of PERG to the standard stimulus field were greater than for the larger field. For both PERG P50 and N95, the differences in their amplitudes between the standard and larger stimulus fields correlated significantly with visual acuity and SD-OCT parameters.
Conclusion: The higher sensitivity and specificity of PERG to the standard stimulus field provide detection of early maculopathy in Stargardt disease, while PERG with the larger stimulus field allows for longer follow-up. The PERG amplitude for the larger stimulus field correlated with severity of transverse photoreceptor loss in SD-OCT. These methods are complementary for evaluation of progression of photoreceptor damage in patients with Stargardt disease.