Quantifying Choroidal Neovascularization Volume

Spectral-domain (SD) OCT was performed using the SD-OCT device (Bioptigen, Inc., Durham. NC, USA) as described previously.^{23 (link)} Images were captured using the following parameters: rectangular scan: 1000 A-scans per B-scan, 100 B-scans per frame. Total retinal thicknesses were measured perpendicular to the surface of the RPE layer and 500 μm away from the center of the optic nerve at 12, 3, 6, and 9 o'clock direction with built-in software. All B-scan sections crossing the CNV were selected for analysis. CNV volume (μm³) was calculated with the following formula: Σ_n(a_n·t_n) (in which a_n is the area and t_n the thickness of the nth B-scan). The area of each B-scan passing through a CNV was calculated using ImageJ software (http://imagej.nih.gov/ij/; provided in the public domain by the National Institutes of Health, Bethesda, MD, USA).