Anti-VEGF therapy is broadly effective at reducing fluid accumulation in the retina, but that may not always be the best analog for treatment success, according to a new study.

A total of 917 patients age 50 and older with subfoveal neovascular AMD (nAMD) who were treated with ranibizumab were screened. Approximately one-fifth of eyes with retinal fluid at baseline showed residual subretinal fluid (SRF) at 12 months (19.5%) and 24 months (18.2%). Additionally, a little over one-fourth of eyes with retinal fluid at baseline showed evidence of intraretinal fluid IRF after 12 and 24 months of treatment (27.7% and 27.5%, respectively).

The authors explained that the odds of achieving 20/40 or better vision at months 12 and 24 were similar between eyes with residual and resolved SRF at each time point. However, the odds of achieving 20/40 or better vision at months 12 and 24 were significantly worse in eyes with residual IRF compared with those with resolved IRF at both time points.

“Interestingly, eyes with residual SRF only at months 12 and 24 achieved greater mean vision gains vs. “dry” eyes with completely resolved residual fluid, suggesting from this study that the presence of SRF may not be harmful to vision when anti-VEGF treatment is maintained,” the authors explained in their study. “Presence of SRF has been associated with a lower incidence of macular atrophy, which may in part explain the higher prevalence of eyes with good visual acuity in the presence of SRF.

“These results suggest that as long as patients are receiving regular treatment, residual SRF may not be detrimental to vision. Taken together, these results suggest that a sophisticated approach, including quantitative analyses of the fluid, may be needed in the assessment of retinal fluid during anti-VEGF treatment for nAMD. Future studies would be necessary to elucidate the long-term impact of retinal fluid dynamics on vision in eyes with nAMD and to develop more refined strategies of management.”