Macular and retinal nerve fiber layer analysis in main Bumiputera adults in Sarawak

• Main Author: Ying Jiun, Chong
• Format: Thesis
• Language: English
• Published: 2015
• Subjects: RE Ophthalmology
• Online Access: http://eprints.usm.my/40139/1/Dr._Chong_Ying_Jiun_%28_Ophthalmology_%29-24_pages.pdf; http://eprints.usm.my/40139/

Introduction Optical coherence tomography (OCT) is widely used in the measurement of macula thickness and retinal nerve fiber layer (RNFL) thickness. The normal variation of macular thickness and the normative database of RNFL thickness are known to vary according to ethnicity. However, the ethnic influence has not been thoroughly evaluated. To date, there are no published studies on macular and RNFL data for the main Bumiputera ethnic groups from Sarawak, Malaysia. Objective The aim of this study is to determine and compare the macular and RNFL thickness among the main Bumiputera ethnic groups in the state of Sarawak, Malaysia. Methods This is a cross-sectional population-based study conducted in Hospital Umum Sarawak from March 2012 to November 2013. A total of 338 healthy subjects from three main Bumiputera ethnic groups in Sarawak (129 Malay, 112 Iban, and 97 Bidayuh) aged from 21 to 70 years old were recruited. The macular and RNFL thickness were measured using Spectralis OCT. The mean retinal thickness was obtained according to the nine areas of the Early Treatment Diabetic Retinopathy Study map. The mean RNFL thickness was acquired according to overall area, two quadrants (nasal and temporal), and four sub-quadrants (superior and inferior). Results The mean central macular thickness was 272.64 ± 26.29 μm, 276.87 ± 27.48 μm, and 275.80 ± 23.13 μm for Malay, Iban and Bidayuh subjects respectively. There was significant difference of mean macular thickness between the Malays subjects and Iban subjects in the superior inner (p = 0.014), inferior outer (p = 0.007), and temporal outer (p = 0.014) region. The overall mean RNFL thickness was 102.73 ± 11.92 μm, 104.73 ± 10.40 μm, and 103.28 ± 11.34 μm for Malay, Iban, and Bidayuh subjects respectively. There was significant difference of mean RNFL thickness in the temporal quadrant between the Malays subjects and Iban subjects (p = 0.016). Conclusion The mean macular thickness was significantly thinner in the Malay ethnic group compared to the Iban ethnic group in the superior inner, inferior inner, and temporal outer areas. The mean RNFL thickness in the temporal quadrant was significantly thinner in the Malay ethnic group compared to the Iban ethnic group.