• multifocal electroretinogram
• retinal dysfunction
• retinitis pigmentosa

The diagnosis of retinitis pigmentosa (RP) is made on the basis of characteristic retinal pigmentation changes, visual field defects, and reduction in amplitude or loss of rod scotopic standard electroretinography (ERG) responses, with a possible history of night blindness and a positive family history of RP.¹ Multifocal electrophysiology (mfERG), is a new technique that constructs a topographical map reflecting retinal function.² Reports have suggested that the spatial resolution of mfERG is sufficient to detect focal changes in retinal function as RP progresses.^3–5

We describe a case of early RP in which the amplitude and implicit times of the patient's standard ERG rod and maximal responses were normal in the right eye and equivocal in the left eye. However, the peripheral retinal mfERG amplitude and implicit times were reduced and delayed. These abnormalities were obtained using a custom built wide field mfERG,⁶ which facilitates assessment of a 90 degree retinal field.