Abstract
Purpose:
Pure type 2 neovascularization (NV) is common in some maculopathies including myopic degeneration and angioid streaks, but is relatively rare in AMD. Reticular pseudodrusen (RSD) are located above the RPE, where they have a branching or reticular distribution. They are best seen with spectral domain optical coherence tomography (SD-OCT) and near-infrared reflectance (nIR). Here we describe the occurrence of a pure form of type 2 NV that appears to occur almost exclusively in patients with RSD, lacking other drusen subtypes.
Methods:
A retrospective chart review evaluated all eyes receiving anti-VEGF therapy for AMD by a single practitioner from 2009 to 2014. Patients with pure type 2 NV were included where either pre-neovascular imaging of the involved eye or imaging of the non-neovascular fellow eye was available to determine drusen characteristics. Pure type 2 lesions were defined as those localized entirely to the subretinal space by both fluorescein angiography (FA) and SD-OCT. Drusen type and choroidal thickness (<120um or ≥120um) were determined through a review of multi-modal imaging including nIR, SD-OCT, and color photos.
Results:
Out of 694 patients treated for NV AMD, only 8 patients met the inclusion criteria. Five were female, 3 were male. The mean age was 81 years. Of the 8 patients, 7 (88%) had exclusively RSD (5 in the dry fellow eye and 2 in the study eye prior to developing NV). 6 of the 8 (75%) patients had choroidal thickness <120um in the affected eye; 6 of 8 (75%) had choroidal thickness <120um in the fellow eye. Mean follow up after diagnosis of type 2 NV was 46 months. Eyes with type 2 NV had mean presenting visual acuity (Va) of 20/90. Mean Va at final follow up for these eyes was 20/60. Out of 5 fellow eyes that were initially dry, 2 eyes (40%) subsequently developed NV, both of which were type 2 lesions.
Conclusions:
Pure type 2 NV appears to be rare in AMD, occurring almost exclusively in patients with RSD and thin choroids. We hypothesize that outer retinal ischemia in the presence of drusenoid material in the subretinal space, without sub-RPE material, may predispose to this lesion subtype. In this small series, long-term Va results with anti-VEGF therapy appeared favorable.