Abstract
Background The common variant most strongly associated with myopia is near the GJD2 gene, which encodes retinal gap junctions. Recently, allelic identity at this locus has been associated with cone-driven electroretinograms (ERGs), particularly OFF pathway signals. The i-wave is a late photopic ERG component, thought to originate in retinal OFF pathways. We explored whether this associated with the myopia risk locus.
Methods ERGs were recorded in TwinsUK participants. The i-wave amplitude was measured relative to the preceding trough in the LA3 response by 2 investigators independently. We investigated association between i-wave amplitude and allelic identity, adjusting for age, sex and familial relatedness.
Results Recordings and genotypes were available in 184 people (95% female; mean (SD) age, 64.1 (9.7) years). Mean (SD) i-wave amplitude was 14.5 (6.5) microvolts. Allelic dosage was significantly associated with i-wave amplitude (p=0.027).
Conclusions I-wave amplitude associated significantly with the myopia risk locus, supporting the importance of cone-driven signals in myopia development and adding evidence that this risk locus specifically affects OFF pathway signals.
