Breakthrough Insights from SEEDS-2: Epiretinal Membrane Trends in Singapore

The Singapore Epidemiology of Eye Diseases Study-2 (SEEDS-2), a landmark investigation leveraging advanced optical coherence tomography (OCT), has illuminated critical patterns in epiretinal membrane (ERM) prevalence among Singapore's multi-ethnic population. Conducted by researchers from premier institutions like the Singapore Eye Research Institute (SERI) and the National University of Singapore (NUS), this study builds on the foundational SEED series, offering fresh data on how ERM—a condition where scar-like tissue forms on the retina's surface—affects vision in adults over 40. With Singapore's aging society, these revelations carry profound weight for public health strategies and clinical practice.

ERM, often dubbed macular pucker, can subtly distort central vision, progressing from mild blurring to significant impairment if severe. Unlike more dramatic retinal issues, its insidious onset demands proactive screening, especially as populations age. SEEDS-2's comprehensive OCT scans of 6,762 participants reveal nuanced ethnic variations and modifiable risks, positioning Singapore's academic hubs at the forefront of ophthalmic epidemiology.

What is Epiretinal Membrane? A Step-by-Step Explanation

Epiretinal membrane starts with cells migrating onto the retina's internal limiting membrane post-vitreous detachment—a common age-related event where the gel-like vitreous shrinks and pulls away. These cells proliferate, forming a translucent wrinkle-inducing layer over the macula, the retina's sharp-vision center.

• Stage 1 (mild): Thin membrane with minimal distortion.
• Stage 2 (moderate): Noticeable retinal folding.
• Stage 3 (severe): Thick membrane causing cystoid spaces and vision loss.

Primary ERM arises idiopathically, while secondary links to prior retinal vein occlusion, diabetic retinopathy, or trauma. Symptoms evolve gradually: metamorphopsia (wavy vision), reduced acuity, or contrast sensitivity loss. In Singapore's context, where diabetes rates hover at 11.6% among adults, secondary forms pose escalating threats. Untreated severe cases may necessitate vitrectomy surgery, peeling the membrane—a procedure refined at SNEC, affiliated with NUS.

SEEDS-2 Methodology: Rigorous Population-Based Design

SEEDS-2 draws from the SEED cohort, tracking over 10,000 multi-ethnic Singaporeans since 2004. This phase examined 6,762 eyes using spectral-domain OCT, grading ERM by stages and primary/secondary status. Participants, aged 40+, represented Chinese (43%), Malays (33%), and Indians (24%), mirroring national demographics.

Multivariable logistic regression pinpointed risks, adjusting for confounders like age, gender, and comorbidities. OCT's high-resolution cross-sections enabled precise membrane detection, surpassing fundus photography's limitations. Led by SERI under Duke-NUS and NUS Yong Loo Lin School of Medicine, the study exemplifies Singapore's integrated academic-clinical research ecosystem.

Prevalence Breakdown: Ethnic Disparities Emerge

Age-standardized prevalence of any ERM stood at 16.3% among Chinese, 14.5% in Malays, and 13.6% in Indians—higher overall than earlier SEED-1 figures (12.1%). Primary ERM dominated (11.2%), with secondary at 3.3%. Bilateral involvement affected 2.8%.

Prevalence escalated with age: <1% under 50, surging to 30%+ over 70. Chinese showed elevated rates across severities, underscoring genetic or lifestyle influences. These stats, from NUS-led analysis, highlight screening needs in Singapore's Chinese-majority (74%) populace.

Key Risk Factors for Primary ERM Identified

Primary ERM linked to older age (OR 1.05 per year), female gender (OR 1.34), Chinese ethnicity (OR 1.23 vs Malays, 1.71 vs Indians), and longer axial length (OR 1.19 per mm)—a proxy for myopia prevalence in Singapore (35-40% adults).

Myopia's role ties to posterior vitreous detachment acceleration. No ties to diabetes or hypertension emerged for primary forms, differentiating from Western cohorts. Duke-NUS researchers emphasize axial length screening for high-risk groups.

Photo by Mohamed Marey on Unsplash

Factors Driving ERM Severity: CVD and Glycemic Control

For primary ERM severity, older age (OR 1.04) and cardiovascular disease (OR 2.17) stood out. Secondary severe cases associated with Chinese ethnicity (OR 2.07-2.49) and elevated HbA1c (OR 1.39 per 1% rise), signaling diabetic retinopathy synergy.

CVD's impact likely stems from vascular leakage fueling fibrosis. HbA1c elevation underscores glycemic management's role. SERI's OCT grading refined severity assessment, aiding prognostic models.

Singapore Universities Spearheading the Research

NUS Yong Loo Lin School of Medicine and Duke-NUS Medical School anchor SEEDS-2, with SERI providing epidemiological muscle. Lead author Yanyan Chen and seniors like Ning Cheung (NUS) exemplify interdisciplinary prowess.

This collaboration integrates clinical OCT data with big analytics, training next-gen ophthalmologists. NUS's Centre for Innovation and Precision Eye Health pioneers AI-OCT for ERM detection, potentially slashing screening costs. Duke-NUS's population health focus translates findings to policy, bolstering Singapore's 'Smart Nation' health tech.

Explore SERI's ongoing trials via their program page.

Clinical and Public Health Implications for Singapore

With 16% ERM prevalence, especially in Chinese elders, routine OCT screening gains urgency. Singapore's polyclinics could integrate AI-assisted scans, targeting CVD patients and myopes. Glycemic control campaigns for diabetics may curb secondary progression.

Economic toll: vision impairment costs SGD 1.5B yearly; early ERM intervention averts this. MOH's Vision 2030 aligns, funding SERI expansions. For frail elderly, gaps persist—SEEDS-2 advocates tailored outreach in heartland clinics.

Comparing SEEDS-2 to Global and Prior Local Data

SEEDS-2's 15% any-ERM exceeds Beijing Eye Study (7%) but aligns with prior SEED (12%). Chinese higher rates mirror Tohoku Megabank (Japan), suggesting East Asian predisposition. Western rates (5-10%) lag, possibly detection variances.

Consistent risks: age, gender, myopia. Novel: CVD for severity, HbA1c for secondary. Full study details here.

Future Outlook: From SEEDS to Precision Ophthalmology

SEEDS-3 eyes 12-year longitudinals, probing ERM progression genetics via genomics. NUS AI models predict severity from OCT, trialing tele-ophthalmology for HDB heartlands. Vitrectomy refinements at SNEC target early severe cases.

Stakeholders: MOH for subsidies, community groups for awareness. Researchers urge myopia control to blunt axial length risks.

Photo by kub liz on Unsplash

Actionable Insights for Singaporeans and Clinicians

• Annual eye checks post-50, prioritizing CVD/diabetes patients.
• Lifestyle: BP control, HbA1c monitoring, myopia management.
• Clinicians: OCT over fundus for ERM, ethnic-tailored counseling.

Singapore's academic excellence positions it to lead Asia in ERM mitigation, enhancing quality of life amid longevity gains.