Patient Age, Imaging Features and Fellow Eye Status Affect Visual Acuity in iAMD

When researchers classified intermediate AMD into four groups based on presence of iRORA and SDD on multimodal imaging, eyes with both subretinal drusenoid deposits and iRORA had worse visual acuity compared to those with neither high-risk feature. Photo: Anna Bedwell, OD. Click image to enlarge. Baseline visual acuity (VA) is a reliable indicator of final visual outcome in patients with age-related macular degeneration (AMD). Since intermediate AMD (iAMD) has a high risk of progression to advanced disease, these patients are typically chosen for AMD clinical trials; however, the correlation between VA and various phenotypes of this AMD stage—such as those with high-risk features on OCT—remains ambiguous. A new study in the journal Eye aimed to clarify this relationship to enhance the design and accuracy of future trials on AMD treatment.The study analyzed baseline VA data of 983 eyes from 805 patients diagnosed with iAMD in at least one eye. The average patient age was 75.8 years, and 35% of the cohort was male. After analyzing patients’ OCT and fundus autofluorescence images, the researchers classified the cohort into four groups:(i) iAMD with no evidence of incomplete retinal pigment epithelial and outer retinal atrophy (iRORA) or subretinal drusenoid deposits (SDD)(ii) iAMD with SDD but without iRORA(iii) iAMD with iRORA but without SDD(iv) iAMD with both iRORA and SDDThe data showed that eyes exhibiting iRORA combined with SDD demonstrated lower VA compared to those with neither imaging feature (odds ratio: 0.98). Increased age (sex-adjusted odds ratio: 1.07) as well as female gender (age-adjusted odds ratio: 0.75) were associated with SDD.The status of the fellow eye also had implications for VA. The better-seeing eye had a significantly higher VA than the worse-seeing eye. When iAMD eyes were classified based on the condition of the fellow eye (iAMD/iAMD; iAMD/neovascular AMD and iAMD/geographic atrophy), the researchers observed “a significant difference in mean VA comparing better and worse-seeing eyes in bilateral iAMD in these categories.” Specifically, eyes with neovascular AMD in the fellow eye had reduced odds of iRORA in the study eye with iAMD (adjusted odds ratio: 0.60). Conversely, eyes with geographic atrophy in the fellow eye were more likely to exhibit iRORA in the study eye (adjusted odds ratio: 3.30).These findings present several important implications for the future design of clinical trials investigating interventions for iAMD. In the discussion portion of their paper, the researchers underscore the importance of considering the baseline characteristics of patients—particularly age, the presence of SDD and iRORA and the fellow eye status. They also caution that, since older patients were more likely to present with SDD (but not iRORA), “if trial cohorts are skewed to the older age groups (75 years or above), a high proportion are likely to have SDD.”Since only 7.2% of the cohort with iAMD had a VA of <70 letters, the researchers also argue that “trial designs need to consider whether the aim is to assess 15 letter gain or loss.” They elaborated, “The baseline VA in most iAMD eyes is high, and so, an outcome of preventing 15 letter loss is more appropriate.”In summary, the authors propose that future trials for iAMD treatment and prevention should ensure that cohorts are stratified based on patient age, multimodal imaging features and fellow eye status to improve the likelihood of detecting significant treatment effects.Click here for the journal source. Gurudas S, Marques I, Girmens JF, et al. Visual acuity in various phenotypes of intermediate age-related macular degeneration (AMD) in a multicentre cohort study in Europe- INTERCEPT-AMD report 1. Eye. [Epub ahead of print]. This article was developed by the editorial staff in conjunction with experts in the field. In the process, AI may have been among the editorial tools used to meet the goals of human editors, who approved all content.