Optical coherence tomography angiography in inactive type 2 neovascularization undergoing monthly anti-VEGF treatment

Abstract

Purpose : To characterize the quantitative and qualitative changes of inactive type 2 Choroidal Neovascolarization (CNV) by means of Optical Coherence Tomography Angiography (OCTA), in eyes undergoing monthly ranibizumab injections for neovascular age related macular degeneration (nAMD).

Methods : Fourteen consecutive patients with nAMD treated with monthly ranibizumab injections were prospectively enrolled. At each month, ophthalmologic evaluation included: visual acuity (ETDRS charts) measurement, fundus biomicroscopy, and Spectral Domain-Optical Coherence Tomography (SD-OCT) B-scan. OCTA (3X3 mm and 6x6 mm macular cube images) was also performed after the loading phase (three injections). All nAMD eyes, showing neither intra nor subretinal fluid on B-scan SD-OCT for 3 consecutive monthly visits after the loading phase, were considered as inactive and their CNV area on OCTA images was manually delineated (baseline examination) using ImageJ software (United States of National Institutes of Health).

Results : Twelve eyes of 12 patients (5 Female/ 7 Male; mean age 75.6+/-9.4 years) showing inactive CNV were considered for the analysis. Two out of 12 eyes were excluded because of presence of low-quality images due to instability of fixation. All eyes included were diagnosed with type 2 CNV. Mean duration of symptoms at time of diagnosis was 30.2+/- 27.1 days, and mean size of CNV at FA was 5.65+/-10.35 mm². Mean time from CNV diagnosis to the lesion being inactive was 3.9 months with an average of 3.9 intravitreal injections. Quantitative OCTA analysis revealed a CNV area of 4.99+/-3.99 mm² at baseline examination, which did not change significantly (5.15+/-4.27 mm²; p=0.99) during the follow up. Qualitative OCTA analysis revealed the persistent visualization of the main neovascular complex in 90% of the eyes. However, a subtle shrinkage of vessels at the edge of the lesion and reduction of the fine capillary network within the neovascular lesion was observed in all eyes. (Figure 1)

Conclusions : We demonstrated that type 2 CNVs were still visible on OCTA despite continuous anti-VEGF administration and monthly intravitreal injections of ranibizumab did not affect the size of inactive CNV.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.