Quantifying macular fluid fluctuation in anti-VEGF treated neovascular AMD and its impact on visual acuity - a real world study

Abstract

Purpose : To describe quantitatively the fluctuation of macular fluid characteristics of eyes undergoing anti-vascular endothelial growth factor (VEGF) therapy for neovascular age-related macular degeneration (nAMD), and to relate these to visual acuity (VA) outcomes.

Methods : This is a retrospective analysis of subretinal fluid (SRF) and intraretinal fluid (IRF) in 431 nAMD eyes treated in an Australian retina clinic from 2007 to 2023. We defined several measures of fluctuation in fluid volume, including absolute and relative change of fluid between visits, and standard deviation of volumes. The relationships between these and both initial VA and the change in VA at one, two and three years were analyzed using linear regression.

Results : IRF had the strongest association with initial VA. The coefficient of IRF was -0.07 with an R²=0.18, i.e., for every additional 100nL of IRF, the expected initial VA decreased by 7 logMAR letters. Higher IRF values were associated with a clear decrease in initial VA. There was a statistically significant relationship (p < 0.0001) between SRF, and the sum of SRF and IRF with initial VA. However, there was minimal effect of SRF volume on initial VA (Figure 1).

A regression analysis was conducted to examine the effect of fluctuation metrics for varying combinations of input years (years over the average metrics for each patient) and target years (the year at which the change in VA from baseline was measured). SRF was statistically significant across all analyses, with an estimated coefficient of -0.04, i.e., every additional 100nL of mean SRF across the input years resulted in a decrease of 4 logMAR letters in visual change at the end of the target year. SRF fluctuation was also significant with the mean absolute changes in SRF coefficients ranging from 0.04 to 0.08. The standard deviation of IRF across a patient’s visits was negatively associated with positive visual change, with coefficients ranging from -0.02 to -0.07 (Figure 2).

Conclusions : IRF volume had the strongest negative correlation with initial VA with higher IRF volumes correlating to decreases in vision. In regard to VA change at one, two and three years, fluctuations in SRF levels were associated with increases in VA, whereas IRF fluctuation was associated with decreases in VA.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.

 

Figure 1.

 

Figure 2.