Table 2a. Study Outcomes for Macula-wide Analysis.
| Outcome | Source Modality† | Definition | Variable Type‡ | |
|---|---|---|---|---|
| Drusen Load | RPE drusen complex volume (RPEDC, mm3) | SD OCT | Drusen-RPE combined volume; volume between the inner border of the RPE and outer border of Bruch's membrane14 | Continuous |
| OCT drusen volume (mm3) | SD OCT | Volume of RPEDC abnormal thickening ≥3 SD from the mean of a normative dataset for each pixel location in non-AMD eyes14,18 | Continuous | |
| Drusen area (DA) | Color photo | Total drusen area in the macula | Continuous | |
| GA and Preatrophy | RPEDC abnormal thinning volume (RAT, ×10−3, mm3) | SD OCT | Volume of RPEDC abnormal thinning ≤2 SD from the mean of a normative dataset for each pixel location in non-AMD eyes14,18 | Continuous |
| GA area (DA) | Color photo | Total GA area in the macula | Continuous | |
| GA* | Color photo | Circular area >433 μm in diameter of partial or complete depigmentation of the RPE in any part of the macula,19 equivalent to circle I-1 in Wisconsin Age-Related Maculopathy Grading System17 | Binary | |
| Central GA* | Color photo | GA involving the center of the macula16 | Binary | |
| PRL thinning | SD OCT | Loss of volume of region between inner aspect of the outer plexiform layer and inner border of RPEDC compared with adjacent tissue | Binary | |
| RPE disruption | SD OCT | A clear degradation of the reflectivity and thickness of the RPE layer, with persisting outer retinal layers | Binary | |
| RPE atrophy | SD OCT | A complete absence of RPE or contour break with PRL loss | Binary | |
| RPE atrophy, foveal | SD OCT | RPE atrophy in the location 660 μm around the fovea | Binary | |
| Neovascular | IRF | SD OCT | Round or oval hyporeflective areas within the retinal layers usually located within the nuclear layers | Binary |
| SRF | SD OCT | Area of low reflectivity (less than or comparable to the vitreous gel) between the outer surface of the retina and the RPE | Binary | |
| CNV* | Color photo | CNV determined as present by ≥2 of the following criteria: (1) serous detachment of the sensory retina, (2) hemorrhage, (3) RPE detachment, (4) fibrous tissue, or (5) hard exudate; or disciform scarring or history of treatment for neovascular AMD also was sufficient to label CNV | Binary | |
| Other | Subretinal lesions | SD OCT | Pathology occurring beneath the layers of neurosensory retina and anterior to the RPE, including reticular pseudodrusen, subretinal hyperreflective material, presumed vitelliform lesion, scar, and hemorrhage20,21 | Binary |
| Hyperreflective foci | SD OCT | Focal, well-circumscribed hyperreflective lesions within the neurosensory retina overlying drusen not associated with intraretinal vessels15 | Binary | |
| Visual acuity | ETDRS | Visual acuity scored by letters using ETDRS chart | Continuous | |
| Neurosensory retina volume (mm3) | SD OCT | Volume between internal limiting membrane and outer border of PRL | Continuous |
AMD = age-related macular degeneration; CNV = choroidal neovascularization; DA = disc area; ETDRS = Early Treatment Diabetic Retinopathy Study; GA = geographic atrophy; IRF = intraretinal fluid; RAT = retinal pigment epithelium drusen complex abnormal thinning; RPE = retinal pigment epithelium; RPEDC = retinal pigment epithelium drusen complex; SD = standard deviation; SD OCT = spectral domain optical coherence tomography; SRF = subretinal fluid.
*
Primary study outcomes.
†
Derived from SD OCT imaging; color photo = derived from color fundus photo using Wisconsin Age-Related Maculopathy Grading System.1