Electrophysiological Insights into Neurovisual Dysfunctions in Myopia: A Systematic Review

Myopia is characterized by the unusual convergence of light rays entering the eye, causing them to focus in front of the retina. Electrophysiological tests, largely non-invasive, offer valuable insights into the functionality of retinal and/or visual pathway cells. This systematic review aims to assess whether electrophysiological tests could support the hypothesis that myopia is associated with a significant impairment in neurovisual function. We included observational or interventional studies involving myopic subjects alongside an age-matched control group. Searches were performed in PubMed, Scopus, and Web of Science, utilising keywords, MeSH terms and expressions. The primary outcomes analysed were the amplitude and latency of the electrophysiological tests considered. A total of 11 studies were included, comprising 340 myopic subjects. The tests evaluated were multifocal electroretinography (mfERG), pattern electroretinography (PERG), flash electroretinography (flash ERG), and visual evoked potentials (VEP). A total of 1271 articles were identified. Of these, 11 met the eligibility criteria and were included in this review. Among the 11 studies, 7 using mfERG, PERG, and flash ERG reported an amplitude reduction in myopic eyes compared to controls. In terms of latency, four studies employing mfERG and PERG reported a delay in myopic eyes. The single included VEP study found both reduced amplitude and delayed latency in myopic eyes. The evidence gathered indicates that myopia is associated with functional neurovisual impairment, detectable through ERG and VEP. These findings reinforce the value of such tests as complementary tools for assessing retinal and visual pathway function in myopic individuals.