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OphthalmologyDecember 20180 citations

Retinal Nerve Fiber Layer Thickness in a Multiethnic Normal Asian Population: The Singapore Epidemiology of Eye Diseases Study.

Ho Henrietta, Tham Yih-Chung, Chee Miao Li, Shi Yuan, Tan Nicholas Y Q, Wong Kah-Hie, Majithia Shivani, Cheung Carol Y, Aung Tin, Wong Tien Yin


AI Summary

This study found Indian eyes have significantly thinner RNFL than Chinese/Malay eyes, even after adjusting for factors, highlighting the need for ethnicity-specific normative data to improve glaucoma detection.

Abstract

Purpose

To describe variations in retinal nerve fiber layer (RNFL) thickness based on spectral-domain (SD) OCT in a multiethnic Asian population.

Design

Population-based, cross-sectional study.

Participants

Ethnic Chinese, Malay, and Indian adults older than 48 years without glaucoma who were recruited from the Singapore Epidemiology of Eye Diseases Study.

Methods

All participants underwent standardized systemic and ocular examinations. Retinal nerve fiber layer thickness was measured using SD OCT. Participants with poor-quality scans were excluded. Linear regression models were used to investigate the associations of ocular and systemic factors with average RNFL thickness. Generalized estimating equation models were used to account for correlation between both eyes.

Main outcome measure: Average RNFL thickness.

Results

Four thousand four hundred seventy-five participants (8178 eyes) consisting of 1371 Chinese, 1303 Malay, and 1801 Indian adults contributed to this analysis. Average RNFL thickness measured was 95.7±9.6 μm in Chinese participants, 94.9±10.6 μm in Malay participants, and 87.3±10.6 μm in Indian participants (P < 0.001). Multivariate analysis adjusted for age, gender, and ethnicity revealed a reduction in RNFL thickness with increased intraocular pressure and axial length (P < 0.001 for both), as well as a diagnosis of diabetes (P = 0.04); greater RNFL thickness was associated with increased disc area (P < 0.001), signal strength (P < 0.001), and low-density lipoprotein cholesterol (P = 0.02). When these significant variables were taken into account, the average RNFL thickness of Indian participants was significantly thinner compared with Chinese participants (7.45 μm thinner on average [95% confidence interval, 6.75-8.15 μm; P < 0.001]), whereas there was no significant difference in average RNFL thickness between Malay and Chinese participants (P = 0.15).

Conclusions

Average and regional RNFL thicknesses were significantly thinner in Indian eyes compared with Chinese and Malay eyes. Results of the study highlight the need to acquire more refined normative data for the comparison of individual patients with others of similar ethnic background while accounting for ocular factors that could influence RNFL thickness. This in turn may improve the sensitivity and specificity of glaucoma detection.


MeSH Terms

AdultAgedAged, 80 and overCross-Sectional StudiesFemaleGlaucomaHumansMaleMiddle AgedNerve FibersPrevalenceReference ValuesRetinal Ganglion CellsSingaporeTomography, Optical Coherence

Key Concepts5

The average retinal nerve fiber layer (RNFL) thickness measured in a multiethnic normal Asian population (4475 participants, 8178 eyes) was 95.7±9.6 μm in Chinese participants, 94.9±10.6 μm in Malay participants, and 87.3±10.6 μm in Indian participants (P < 0.001).

EpidemiologyCross-sectionalPopulation-based, cross-sectional studyn=4475 participants (8178 eyes) consist…Ch5Ch10

Multivariate analysis, adjusted for age, gender, and ethnicity, in a multiethnic normal Asian population (4475 participants, 8178 eyes) revealed a reduction in RNFL thickness with increased intraocular pressure and axial length (P < 0.001 for both), as well as a diagnosis of diabetes (P = 0.04).

PrognosisCross-sectionalPopulation-based, cross-sectional studyn=4475 participants (8178 eyes)Ch5Ch10

Multivariate analysis, adjusted for age, gender, and ethnicity, in a multiethnic normal Asian population (4475 participants, 8178 eyes) showed greater RNFL thickness was associated with increased disc area (P < 0.001), signal strength (P < 0.001), and low-density lipoprotein cholesterol (P = 0.02).

PrognosisCross-sectionalPopulation-based, cross-sectional studyn=4475 participants (8178 eyes)Ch5Ch10

In a multiethnic normal Asian population (4475 participants, 8178 eyes), after accounting for significant variables, the average RNFL thickness of Indian participants was significantly thinner compared with Chinese participants (7.45 μm thinner on average [95% confidence interval, 6.75-8.15 μm; P < 0.001]).

Comparative EffectivenessCross-sectionalPopulation-based, cross-sectional studyn=4475 participants (8178 eyes)Ch5Ch10

In a multiethnic normal Asian population (4475 participants, 8178 eyes), after accounting for significant variables, there was no significant difference in average RNFL thickness between Malay and Chinese participants (P = 0.15).

Comparative EffectivenessCross-sectionalPopulation-based, cross-sectional studyn=4475 participants (8178 eyes)Ch5Ch10

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