Ancestry Differences in Longitudinal Visual Field Data in Healthy Eyes in the African Descent and Glaucoma Evaluation Study (ADAGES)

Abstract

Purpose: : We previously reported slightly worse visual function in people of African descent (AD) compared those of European descent (ED). These ancestry differences were spatially distributed along an arcuate pattern, suggesting they may be signs of early disease. The purpose of the present study is to determine whether people of AD with healthy eyes are more likely to develop visual field (VF) defects over time compared to people of ED.

Methods: : Visual function was assessed longitudinally in 41 AD and 41 ED healthy eyes from 32 AD and 27 ED participants enrolled in the ADAGES or Diagnostic Innovations in Glaucoma Study. At baseline, participants had normal appearance of the optic disc on stereophotographs, normal standard automated perimetry (SAP) results (defined as normal GHT and PSD on at least one of the two baseline tests), normal fundus on ocular examination, intra-ocular pressure (IOP) ≤22 mm Hg and no history of elevated IOP, of taking medication to reduce IOP, or of glaucoma surgery. Each participant had two reliable baseline SAP-SITA tests and at least three years of follow-up (FU) data. We determined the percentage of AD and ED eyes with normal SAP results at baseline and confirmed abnormal SAP results (GHT outside normal limits or PSD triggered at 5% or worse) at any point during FU. The Guided Progression Analysis (GPA) was also performed for all FU tests.

Results: : At the participant level, no significant differences were observed for age (AD: 50.7 ± 13.0, ED: 47.2 ± 11.8; p=0.20), high blood pressure (AD: 46.3%, ED: 26.8%; p=0.07), heart disease (AD: 2.4%, ED: 12.2%; p=0.08) and family history of glaucoma (AD: 53.7%, ED: 39.0%, p=0.18). More AD (14.6%) than ED (2.4%) participants had diabetes (p=0.04). Compared to ED eyes (9.8%), a significantly larger percentage of AD eyes (31.7%) had normal SAP results at baseline and confirmed abnormal SAP results during FU (p=0.01). Likely progression (LP) on GPA was observed in 8.1% of AD eyes and in 0% of ED eyes (p=0.08). All AD eyes with LP had abnormal SAP results during FU.

Conclusions: : The larger percentage of AD eyes with abnormal SAP results during FU lends further support to the idea that the ancestry differences in visual function that we previously reported for healthy eyes may have been signs of early disease.

Clinical Trial: : www.clinicaltrials.gov NCT00221923; NCT00221897

Keywords: visual fields • perimetry • clinical (human) or epidemiologic studies: natural history