Kong M, Hwang S, Ko H, et al. - In this investigation involving 361 Korean adults from 89 families with normal healthy eyes, researchers sought to assess the genetic influence on macular ganglion cell inner plexiform layer (GCIPL) thickness. Macular GCIPL thickness has been measured with optical coherence tomography in nine macular subfields defined by the E TDRS. The authors discovered that GCIPL thickness in inner subfields was highest and in fovea was lowest. Monozygotic twin pairs displayed significantly higher intraclass correlation coefficients of GCIPL thickness in all subfields vs those in parent-offspring pairs and sibling pairs. Macular GCIPL thickness is influenced significantly by genetic factors. It differs according to subfields with moderate to high heritability in all subfields.