The ‘journey’ matters: OCT fluctuations correlate with vision gains
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Patients who demonstrated larger fluctuations in central foveal thickness, or CFT, experienced numerically smaller vision gains, according to a post hoc analysis of data from the HARBOR trial presented at the Association for Research in Vision and Ophthalmology annual meeting.
“What we wanted to show was that this stuff matters. It’s not just the beginning and the end, and at the end just because your OCT image is better and ultimately the patient is doing better,” Veeral Sheth, MD, MBA, FACS, clinical assistant professor at the University of Illinois at Chicago, told Healio. “No, it’s the journey that they take that actually matters. What we are showing in this study is that fluctuations correlate with vision gains.”
The HARBOR trial evaluated the use of ranibizumab for the treatment of neovascular age-related macular degeneration among treatment-naive patients. For 24 months, investigators randomly assigned trial participants to receive either 0.5 mg of intravitreal ranibizumab monthly or 2 mg as needed.
“There is no set way to look at variability in these patients,” Sheth said. “There is no set way to look at fluctuations. So, we created a framework to try to quantify that.”
For the post hoc analysis, the researchers included patients from HARBOR who had 16 or more evaluable OCT images taken during month 3 and best corrected visual acuity (BCVA) at baseline and month 24.
“We looked for big fluctuations in OCT’s — that could be the OCT got a lot worse and then got a lot better. The theory behind that is there is an accordion effect on the retina,” Sheth explained. “If you start stretching it out, squeezing it back together, stretching it out, squeezing it back together — that’s actually where damage can happen.”
According to the abstract and presentation, the analysis comprised 849 patients, with 427 randomly assigned to receive monthly doses of ranibizumab and 422 randomly assigned to receive treatment as needed. Patients treated as needed demonstrated more bounces in CFT from month 3 to month 24 compared with patients treated monthly (95% CI, 8.5 [8-9] vs. 3.4 [2.9-3.9]).
When divided — the as-needed group was divided into quartiles — the researchers demonstrated that patients with the least amount of OCT fluctuation demonstrated 10.6 letters of vision gain at month 24 vs. 6.5 letters gained by the quartile demonstrating the most OCT fluctuations. The researchers looked at the type of fluid and its impact on vision gains as well. They demonstrated that in the as-needed group, subretinal fluid (SRF) fluctuations did not appear to impact vision gains at 24 months. Intraretinal fluid (IRF) fluctuations, however, did appear to correlate to vision gains with patients who experienced the least amount of fluctuation in IRF, demonstrating 10.1 letters of vision gained vs. the group demonstrating the most amount of IRF fluctuation — gaining only 5.6 letters at 24 months.
The investigators suggested that future research should focus on the impact of early CFT bounces on longer-term treatment responses.
“We took an old data set and we started to dig a little deeper; we found some patterns that we believe are meaningful. A lot of this type of interesting information is out there already,” Sheth said. “We just have to start asking the right questions and figure out how to dig into some of these previous data sets.”
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Sheth V. Fluctuations in Central Foveal Thickness and Vision Outcomes With Anti-VEGF Therapy for Neovascular Age-Related Macular Degeneration. Presented at: Association for Research in Vision and Ophthalmology annual meeting; May 6, 2020 (virtual meeting).
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