Multifocal electroretinogram in patients with X-linked juvenile retinoschisis

Purpose. A multifocal electroretinogram (MFERG) based on binary m-sequences provides functional mapping of human retina. We applied the MFERG to evaluate retinal distribution of cone ERG in patients with X-linked juvenile retinoschisis (XLJR) . Methods. We examined 8 male patients with XLJR. The age of the patients ranged from 13 to 34 years (average 20 years). All eyes of 8 patients showed abnormal foveal appearance, and three eyes of three patients showed peripheral retinoschisis involving the testing field of MFERG. Each local response was obtained using multifocal technique (Sutter and Tran, Vision Res, 1992). A Burian-Allen bipolar contact lens electrode was used for signal derivation. Results. MFERG in all patients demonstrated severely attenuated responses at the fovea and various degrees of amplitude reduction outside the fovea. Amplitudes at peripheral schisis were relatively preserved in spite of severe abnormality of psychophysical sensitivity. Implicit time of MFERG was significantly delayed at all locations. Conclusion. Retinal dysfunction in XLRS is more manifest at the fovea. Variety of amplitude reduction outside the fovea in 8 patients suggested either severity or stage of the disorder. Peripheral schisis might not contribute the reduction of cone ERG in its early stage.