Abstract
Purpose:
To determine the prevalence of outer retinal tubulation (ORT) seen on spectral domain optical coherence tomography (SD-OCT) in eyes with neovascular age-related macular degeneration (ARMD) following anti-VEGF therapy, and to correlate ORTs with intra-retinal fluid (IRF), subretinal fluid (SRF), and retinal, subretinal fluid, and subretinal tissue complex (SRTC) thickness.
Methods:
Participants in CATT were randomly assigned to ranibizumab (0.5mg) or bevacizumab (1.25mg) treatment and to a monthly or PRN injection dosing regimen. A subset, 81 eyes had SD-OCT scans beginning at Week 56. The original CATT grading protocol did not distinguish ORTs from cysts in eyes with IRF, or ORTs from small SRF pockets in eyes with SRF. Accordingly the subset of 58 eyes at Week 56 with IRF and SRF was selected for ORT analysis. Horizontal SD-OCT B-scan images as determined by the CATT OCT Reading Center, were evaluated. Cirrus 512x128 or Spectralis 20°x20° volume cube scan protocols were used to acquire SD-OCT images. 2 independent readers graded scans, and a senior reader arbitrated discrepant grades. The prevalence of ORTs, identified as a tubular structure seen on at least 3 consecutive Cirrus B scans or 2 consecutive Spectralis B scans was determined. Retinal, SRF, and SRTC foveal center thicknesses were compared in eyes with and without ORTs.
Results:
Of the 81 eyes, 7 (8.4%) had ORTs. Among the 38 eyes with IRF, 7 (18.4%) also had ORTs and among 20 eyes with only SRF none had ORTs. Among eyes with IRF and ORT, the mean foveal center retinal, SRF, and SRTC thicknesses were 116.1±40.6, 4.7±12.5 µm, and 96.4±68.3, respectively. The corresponding mean thicknesses in eyes without ORTs were 180.6±92.5µm, 4.8±18.6µm, and 146.9±126.8µm respectively. The difference in mean retinal thickness (64.5 µm) in eyes with and without ORTs was statistically significantly (p=0.009).
Conclusions:
ORTs were seen relatively commonly in eyes with neovascular AMD and residual IRF following anti-VEGF therapy. Eyes with ORTs had thinner retinas than those without ORTs. These findings suggest that ORTs are related to degenerative changes in neural tissue in eyes with residual IRF.
Keywords: 412 age-related macular degeneration •
550 imaging/image analysis: clinical