Myopic Maculopathy and Optic Disc Changes in Highly Myopic Young Asian Eyes and Impact on Visual Acuity VICTOR KOH, COLIN TAN, PEI TING TAN, MARCUS TAN, VINAY BALLA, GERARD NAH, CHING-YU CHENG, KYOKO OHNO-MATSUI, MELLISA M.H. TAN, ADELINE YANG, PAUL ZHAO, TIEN YIN WONG, AND SEANG-MEI SAW PURPOSE: To determine the prevalence and risk factors and was associated with older age (odds ratio of myopic maculopathy and specific optic disc and macu- [OR] 1.66; 95% CI: 1.22, 2.26), reduced choroidal lar changes in highly myopic eyes of young Asian adults thickness (OR 0.99; 95% CI: 0.98, 0.99), and increased and their impact on visual acuity. axial length (AL) (OR 1.52; 95% CI: 1.06, 2.19). DESIGN: Prospective cross-sectional study. The presence of disc tilt, posterior staphyloma, and METHODS: In total, 593 highly myopic (spherical chorioretinal atrophy were associated with reduced visual equivalent refraction [SER] less than L6.00 diopters acuity. [D]) and 156 emmetropic (SER between L1.00 CONCLUSIONS: Our study showed that myopia-related and D1.00 D) male participants from a population- changes of the optic disc and macula were common in based survey were included. All participants underwent highly myopic eyes even at a young age. The risk factors standardized medical interviews, ophthalmic examina- for myopic maculopathy include increased age, longer tion, and color fundus photographs. These photographs AL, and reduced choroidal thickness. Some of these were graded systematically to determine the presence of changes were associated with reduced central visual optic disc and macular lesions. Myopic maculopathy was function. (Am J Ophthalmol 2016;164:69–79. classified based on the International Classification of Ó 2016 by Elsevier Inc. All rights reserved.) Myopic Maculopathy. RESULTS: The mean age was 21.1 ± 1.2 years. The mean SER for the highly myopic and emmetropic group YOPIA IS A MAJOR CAUSE OF VISUAL IMPAIRMENT was L8.87 ± 2.11 D and 0.40 ± 0.39 D, respectively in the world1,2 and the prevalence is especially (P < .001). Compared to emmetropic eyes, highly M high in East Asia.3 In Asia, the prevalence of myopic eyes were significantly more likely to have optic myopia (spherical equivalent refraction [SER] less disc tilt, peripapillary atrophy (PPA), posterior staphy- than À0.50 diopters [D]) and high myopia (SER less loma, chorioretinal atrophy, and myopic maculopathy than À6.00 D) in young adults (age range 18–24 years) (all P < .001). The main findings included PPA are 81.6%–96.5% and 6.8%–21.6%, respectively.4–7 In (98.3%), disc tilt (22.0%), posterior staphyloma addition, a study in Singapore comparing similar cohorts (32.0%), and chorioretinal atrophy (8.3%). Myopic of young Asian men (aged 16–25 years) between 1996– maculopathy was present in 8.3% of highly myopic eyes 97 and 2009–10 showed that the prevalence of myopia and high myopia remained high in the latter group— 81.6% and 14.7%, respectively.4 This group of young myopic adults could pose a significant public health prob- Supplemental Material available at AJO.com. lem in the future. Accepted for publication Jan 23, 2016. Complications associated with pathologic myopia can From the Vision Performance Centre, Military Medicine Institute, be irreversible and result in significant ocular morbidity. Singapore (V.K., M.T., G.N., P.Z.); Department of Ophthalmology, National University Health System, Singapore (V.K., M.T., V.B., This includes myopic choroidal neovascularization, C.C.-Y.); Department of Ophthalmology, Tan Tock Seng Hospital, chorioretinal atrophy, and foveoschisis. These sight- Singapore (C.T.); Biostatistics Unit (P.T.T.) and Department of threatening conditions result in reduced quality of life Ophthalmology (T.Y.W., S.S.-M.), Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Singapore Eye Research and increased socioeconomic burden, especially if they 8 Institute, Singapore National Eye Centre, Singapore (C.C.-Y., T.Y.W., occur early in life. In the Singapore Cohort Study of S.S.-M.); Department of Ophthalmology and Visual Science, Tokyo Risk Factors for Myopia (SCORM) study (age range Medical and Dental University Graduate School of Medicine, Tokyo, Japan (K.O.-M.); and Defence Medical & Environmental Research 12–16 years), the prevalence of optic disc tilt and peripa- Institute, DSO National Laboratories, Singapore (M.M.H.T., A.Y.). pillary atrophy for children with SER less than À6.00 D Inquiries to Prof Seang-Mei Saw, Department of Epidemiology and (n ¼ 89) was 67.5% and 92.2%, respectively. Interest- Public Health, Yong Loo Lin School of Medicine, National University of Singapore, MD 3, Level 16 Medical Dr, Singapore 117597; e-mail: ingly, compared to older myopic adults (aged more [email protected] than 40 years), the prevalence of these myopic 0002-9394/$36.00 Ó 2016 BY ELSEVIER INC.ALL RIGHTS RESERVED. 69 http://dx.doi.org/10.1016/j.ajo.2016.01.005 maculopathies was much lower in these highly myopic ocular surgery that may alter the refractive status of the children (only 1 case each of posterior staphyloma and eye; and those who were unwilling or unable to take lacquer cracks).9–12 Electrophysiology studies have also part in the study or unable to return for scheduled visits. shown that the myopic retinas of adolescents and Written informed consent were taken from the subjects young adults have diminished amplitudes and delayed and their parents/guardians (if they were below 21 years latency despite a normal-looking retina.13 This evidence of age). The study was conducted in accordance with suggested that myopia-related structural changes in the the tenets of the World Medical Association’s Declara- retina could be age- and time-dependent. On the other tion of Helsinki and had ethics approval from the Sing- hand, in population-based studies, among adults older health Centralized Institutional Review Board. than 40 years with high myopia (SER less than À5.00 D), only a relatively small proportion (0.9%–3.29%) INTERVIEW, VISUAL ACUITY MEASUREMENT, AND develop structural changes.10,14,15 It is possible that REFRACTION: All the participants who fulfill the inclu- apart from axial length (AL) and SER, there are other sion criteria and consented to the study underwent a contributing risk factors leading to pathologic myopic standardized interview regarding their refraction status, changes. To date, there is little literature on the visual including the age at which they started wearing glasses impact of pathologic myopia and when these myopia- and the age at which their spherical refractive error first related changes affect highly myopic young adults. This reached À6.00 D. Best-corrected visual acuity (BCVA) is important in the assessment of visual potential because measurement and subjective cycloplegic refraction were visual impairment at this young age group has significant conducted on the same day by a trained optometrist. impact on long-term visual prognosis and rehabilita- The subjects’ monocular VA was measured using the log- tion.14 arithm of the minimal angle of resolution (logMAR) We aim to describe the prevalence of myopic maculop- chart (Lighthouse International, New York, New York, athy and related structural abnormalities, including specific USA) at 4 meters. If the largest number could not be myopia-related optic disc and macular changes in a group identified at 4 meters, the chart was brought closer to of highly myopic (SER less than À6.00 D) young Asian the subject, then counting fingers, hand motion, or light men and compare them with emmetropic eyes of the perception vision was assessed. Cycloplegia was induced same age group. We will also examine the risk factors for with 3 drops of cyclopentolate 1% 5 minutes apart. At these myopia-related changes and their impact on visual least 30 minutes after the last drop, subjective cyclople- acuity. gic refraction tests were performed by the same optome- trist for all the participants. SER was calculated as the sum of the spherical power and half of the cylindrical power. METHODS OCULAR EXAMINATION AND IMAGING: Ocular biom- STUDY POPULATION: The current study was conducted etry was performed using the IOL Master (Carl Zeiss between January 1, and December 31, 2012 and the meth- Meditec AG, Jena, Germany), which included AL odology for subject recruitment was detailed elsewhere.16 measurements. The mean of 3 AL measurements was taken Briefly, a total of 28 908 young male subjects aged 19–25 as the final AL. All the subjects underwent a standardized years underwent noncycloplegic autorefraction (Huvitz and detailed examination of the anterior segment at the MRK-3100P, Republic of Korea) as part of a compulsory Singapore Eye Research Institute by a trained ophthalmol- ophthalmic examination for pre-employment screening ogist. Slit-lamp examination included assessment of cornea in Singapore. Out of 2584 persons identified to have and lenticular pathology and anterior chamber depth. high myopia (SER less than À6.00 D) based on noncyclo- Goldmann applanation tonometry was used to measure plegic autorefraction, 719 subjects were selected based on the intraocular pressure in mm Hg. Retinal photography refractive error–stratified random sampling strategy. They was performed by a trained ophthalmic technician using were invited to participate in the current study and under- the Canon CR-DGI (Canon Inc, Tokyo, Japan) nonmydri- went further examination and investigations at the atic retinal camera after pupil dilation. Seven retinal pho- Singapore Eye Research Institute as described below. tographs were taken to obtain the view of the optic disc For the control group, 168 emmetropic male subjects (disc-centered and rotated at 30 degrees to the right and (SER between À1.00 and þ1.00 D) were recruited and 30 degrees to the left), macular view, and right and left up- underwent the same standardized examination and inves- per and lower arcade peripheral views from both eyes.