OCT Biomarkers Foretell Treatment Need in Retinal Vein Occlusion Macular Edema

Patients with macular edema due to retinal vein occlusion (RVO) who have greater baseline disorganization of the retinal inner layers (DRIL) and higher central subfield thickness (CST) 3 months after initiating treatment with ranibizumab may require more frequent injections after 7 monthly doses, according to findings published in the American Journal of Ophthalmology. Researchers suggest the spectral-domain optical coherence tomography (SD-OCT) biomarkers can predict the total burden and frequency of ranibizumab injections required to treat RVO-associated macular edema.

The researchers performed a post-hoc analysis of 95 patients who received 7 monthly doses of ranibizumab followed by either as-needed or nonrandomized monthly injections from months 7 to 15 in eyes with macular edema secondary to RVO. The study assessed CST, epiretinal membrane presence, intraretinal and subretinal fluid, hyperreflexive foci, DRIL, and the disruption of the external limiting membrane, ellipsoid zone, or interdigitation zone. They evaluated the association between these SD-OCT biomarkers and ranibizumab injection frequency using univariate and multivariable regression analysis. 

Eyes with branch retinal vein occlusion or hemiretinal retinal vein occlusion (BRVO/HRVO) made up 57.9%, while 42.1% of eyes had central retinal vein occlusion (CRVO). The study found that mean BCVA improved (+17.5 ETDRS letters [SD, 1.2]) during the 7-month fixed dosing period, remaining stable from baseline (+20.1 [SD, 1.5] ETDRS letters) during the PRN phase from months 7 to 15. The mean number of PRN injections was 4.32 (SD, 2.35). Greater baseline DRIL (0.021, P =.0275) and higher CST at month 3 (0.01, P <.001) were associated with higher total number of PRN injections on multivariate regression analysis.

Baseline SD-OCT features and initial anatomical response to ranibizumab therapy may be associated with ranibizumab treatment burden when given PRN for RVO-related macular edema, noting that this information may be clinically useful.

“These image biomarkers may help guide risk stratification, disease prognosis, follow-up intervals, and patient counseling in the management of patients with RVO,” according to the researchers.

Study limitations include small sample size, post-hoc exploratory analysis approach, and the fact that OCT biomarkers were analyzed only at baseline.