Retinal tests

Summary Visual symptoms are often non‐specific and fundus signs such as disc pallor can result from retinopathy or optic neuropathy. Retinal and macular pathologies may not be evident on clinical examination and visual electrophysiology provides an objective method of localising dysfunction along the visual pathway. This presentation will focus on the assessment of macular function using pattern and multifocal electroretinography (PERG; MfERG) and on the characterisation of retinal function using full‐field electroretinography (ERG). The comparison of PERG or MfERG with ERG allows differentiation between macular and generalised retinal dysfunction. Pattern ERG may also be used to assess retinal ganglion cell function and complements cortical visual evoked potential (VEP) assessment of optic nerve and post‐retinal function. Objective assessment of macular function (PERG/MfERG) is usually essential to exclude a macular cause of VEP abnormality and normal retinal electrophysiology may prompt the need for additional VEP testing or neuroradiology. The use of these techniques will be highlighted using illustrative cases.