Sadda et al Wet AMD: Lesion Changes with Ranibizumab Table 1 (available online only). Glossary of Reading Center Definitions Term Definition Classic CNV Characterized by well-demarcated areas of hyperfluorescence discerned in the early phase of the fluorescein angiogram. In the late phase of the angiogram, progressive pooling of dye appears in the overlying subsensory retinal space and usually obscures the boundaries of the CNV. Occult CNV Appearance varies. Fibrovascular PED is a type of occult CNV in which areas of usually irregular elevation of the staining/leaking RPE are detectable on stereoscopic angiography within 1 to 2 min after fluorescein injection. Persistence of fluorescein staining or leakage within this area occurs within 10 min after fluorescein injection. These areas are not as bright as areas of classic CNV or serous detachments of RPE in the early phase of the angiogram. Late leakage of undetermined source is a rare type of occult CNV in which poorly demarcated areas of leakage appear at the RPE level in the late phase of the angiogram without well-demarcated areas of hyperfluorescence discernible in the early phase of the angiogram that account for the leakage. CNV lesion An entire complex of components (e.g., CNV, elevated blocked fluorescence, thick blood) is considered to constitute the neovascular lesion. Lesion components may include CNV (classic or occult), thick blood, blocked fluorescence (due to pigment or a scar that obscures the neovascular border), and serous detachments of the RPE. Lesion components also include contiguous flat blocked fluorescence, fibrous tissue, and thin flat scars. For digital angiograms, lesion components are measured in millimeters squared using the available planimetry tools. For film angiograms and color photographs, lesion components are measured in disc areas using an acetate grid overlying the image. All areas are converted to disc areas for analysis. CNV leakage An area of hyperfluorescence that increases over time and often displays illdefined or fuzzy borders. Total area of leakage includes intense progressive RPE staining to capture fibrovascular PEDs (or parts of them) that show intense staining in late frames while excluding fibrovascular PEDs that do not leak and in which staining fades in late frames. Thin flat scars and serous PEDs that do not leak but in which hyperfluorescence does not fade are also excluded. An obvious white or yellow mound of fibrous tissue that is well defined in shape, appears solid, and obscures the RPE and choroid. A disciform scar (or other Disciform scar fibrous tissue) may demonstrate blocked fluorescence and/or staining on angiography. If accompanied by CNV, scars also may demonstrate leakage on angiography. Subretinal fibrous tissue (or fibrin) In color photographs, fibrous tissue is visible as sheets or mounds of white material under the retina in eyes with age-related macular degeneration, usually representing fibrous or fibrovascular tissue that has proliferated in areas previously occupied by serous or hemorrhage subretinal fluid. Early in the development of such scars, the white material may be fibrin. No attempt is made to distinguish between fibrin and fibrous tissue in the classification. SSRD Caused by accumulation of fluid under the sensory retina and visible in stereoscopic photographs as a separation between the retina and underlying RPE. Retinal blood vessels provide the best landmark for determining its position. Presence and extent are determined from an examination of color or red-free photographs as well as an angiogram. When fluorescein leakage from Sadda et al Term Wet AMD: Lesion Changes with Ranibizumab Definition CNV is intense, this hyperfluorescence helps to demonstrate presence and extent of SSRD. Table 1 (available online only). Glossary of Reading Center Definitions (cont’d) CNV = choroidal neovascularization; PED = pigment epithelial detachment; RPE = retinal pigment epithelium; SSRD = serous sensory retinal detachment.