Correlation of structural and electrophysiological changes in the retina of young high myopes Victor Koh 1,2 , Clement Tan 2 , Gerard Nah 1 , Paul Zhao 1,3 , Adeline Yang 4 , Sheng Tong Lin 4 , Tien Yin Wong 2,5,6 , Seang Mei Saw 7 and Audrey Chia 5,8 1 Singapore Armed Forces Vision Performance Centre, Military Medicine Institute, Singapore, 2 Department of Ophthalmology, National University Hospital, National University Health System, Singapore, 3 Republic of Singapore Air Force Medical Service, Singapore, 4 DSO National Laboratories, Singapore, 5 Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, 6 Department of Ophthalmology, NUS, Singapore, 7 Department of Epidemiology and Public Health, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, and 8 Singapore National Eye Centre, Singapore, Singapore Citation information: Koh V, Tan C, Nah G, Zhao P, Yang A, Lin ST, Wong TY, Saw SM & Chia A. Correlation of structural and electrophysiological changes in the retina of young high myopes. Ophthalmic Physiol Opt 2014; 34: 658–666. doi: 10.1111/opo.12159 Keywords: Asian eyes, electroretinography, myopia, optical coherence tomography Correspondence: Adeline Yang E-mail address: yhuixian@dso.org.sg Received: 26 February 2014; Accepted: 4 September 2014 Abstract Purpose: Despite a high prevalence of myopia among young East Asian adults, there is a lack of data on the myopic retina structure-function relationship in this group. We examined the association between optical coherence tomography (OCT) and electroretinogram (ERG) measurements in highly myopic young Asian adults to provide this information and also determined if OCT can be used as an alternative screening tool to assess retinal function in young myopic adults. Methods: This was a prospective study comprising young adults aged between 18 and 25 years with spherical equivalent refraction of worse than À6.00 D. A com- prehensive ophthalmic examination comprising fundus examination and grading, ocular biometry, time-domain OCT (fovea, macular and retinal nerve fibre layer thickness) and ERG (full field and multifocal) were performed for all the eyes. Results: A total of 32 eyes (mean spherical equivalent Æ standard deviation À10.17 Æ 1.51 D, mean age 23.8 Æ 1.3 years) were included. None of the eyes showed visible myopic retinopathy and the central retina thickness of all eyes was classified as within the normal range. Full-field ERG amplitude and multifocal ERG P1 amplitudes in the outer rings (R3-R5) were, however, inversely associated with axial length. The multifocal ERG P1 amplitudes were also positively corre- lated with mean retinal nerve fibre layer thickness in R2, 4, 5 rings and outer mac- ular thickness in R 2–5 rings. Conclusion: These findings suggest that full field ERG changes may precede fun- dus and OCT changes in highly myopic young adults. Although there was some correlation between multifocal ERG amplitudes with OCT outer macular and ret- inal nerve fibre layer thickness, the OCT may not be useful as a retinal function screening tool, being within normal limits in all eyes. Further longitudinal studies are required to determine how the relationship between ERG and OCT will evolve over time. Introduction Myopia and its associated complications (e.g. myopic macular degeneration, retinal detachment) are a major cause of visual impairment, especially in East Asia. 1–3 In Singapore, nearly 80% of young adult males (aged 16– 25 years) have been reported to have myopia with 13% having high myopia (worse than À6.00 D) 4 and this is consistent with other similar studies in Asia. 5,6 Unlike older adults with myopia, there are less myopia-related structural changes of the macula in the younger age group such as posterior staphyloma, choroidal neovascularisation and lacquer cracks. Studies showed that the prevalence of myopic complications (such as myopic maculopathy) © 2014 The Authors Ophthalmic & Physiological Optics © 2014 The College of Optometrists Ophthalmic & Physiological Optics 34 (2014) 658–666 658 Ophthalmic & Physiological Optics ISSN 0275-5408