MACULAR THICKNESS MEASURED BY OPTICAL COHERENCE TOMOGRAPHY IN HEALTHY OLDER ADULTS FROM THE CITY OF PARINTINS, BRAZILIAN AMAZON REGION

Abstract

Purpose: To provide normative values of macular thickness in a subset of participants of a population-based ocular eye survey using SD-OCT.

Methods: The Brazilian Amazon Region Eye Survey (BARES) is an ongoing cross-sectional population-based study to determine prevalence and causes of visual impairment, blindness and ocular diseases in adults aged 45 years and older in urban and rural areas of the city of Parintins. Sixty-four eyes of 64 healthy normal subjects (28 males), aging from 45-65 (mean= 52±5) had a comprehensive ophthalmic exam. All selected participants had best corrected visual acuity ≥ 20/32, normal eye exam and no prior ocular surgery. OCT was performed using standard scanning protocols and retinal full thickness in Early Treatment Diabetic Retinopathy Study (ETDRS) subfields was assessed. Retinal thickness was calculated for 9 subfields from the inner and outer retinal boundaries. The associations between thickness measurements with age, gender, refractive errors and schooling level were investigated. Statistical significance was established at ≤0.05.

Results: The average central foveal thickness was 252.3±19.2µm. Age was negatively correlated with macular thickness in the following areas: inner foveal layer (p=0.020); inner nasal (p=0.004) and inferior (p=0.002) parafovea; outer layer of nasal (p=0.016), superior (p=0.000) and inferior (p=0.045) parafovea; nasal (p=0.001) and superior (p=0.026) perifovea. Macular thickness showed to be larger in males in the following areas: temporal parafoveal total thickness (p=0.0198), temporal inner parafoveal (p=0.0058) and nasal outer parafoveal (p=0.033). There was no relationship between macular thickness and spherical equivalent. The data suggested a negative correlation between schooling educational level and decrease in retina thickness for inner (p=0.020) and outer foveal areas (p=0.000).

Conclusions: The current results provide a normative database of macular thickness in healthy Brazilian Amazon population using SD-OCT. We suggest that age should be considered while interpreting the retina thickness. These parameters will be useful to characterize retinal disorders in future studies in this population.