Maguire, Maureen G.

Purpose: To evaluate agreement between eye banks (EBs) and a reading center on endothelial cell density (ECD) determinations in the Cornea Preservation Time Study. Methods: The Cornea Image Analysis Reading Center (CIARC) performed variable frame image analysis on EB-obtained–preoperative central endothelial images (after lamellar dissection for Descemet stripping automated endothelial keratoplasty by the EBs or before shipping, if surgeon prepared) to determine ECD. The EBs performed their usual method of ECD determination. The CIARC and EBs also provided ECD determinations from screening central endothelial images taken by the EBs during donor evaluation. Two independent masked CIARC readers determined ECD with measurements averaged. Results: The mean preoperative ECD was 15 cells/mm2 greater by the EBs than by CIARC (N = 1286, P < 0.001) with 95% limits of agreement of (−644, 675 cells/mm2). The limits of agreement in preoperative ECD were wider in the After-Lamellar-Dissection Group (−687, 683 cells/mm2) than in the Before Shipping Group [(−505, 633 cells/mm2); P = 0.03]. The EBs-determined preoperative ECD was within 10% of the CIARC-determined ECD for 886 (69%) image sets, with 236 (18%) higher by >10% and 164 (13%) lower by >10%. Excellent agreement appeared between the EBs and CIARC when 100–300 cells could be analyzed in contrast to <100 cells (SD = 308 cells/mm2 vs. SD = 603 cells/mm2; P < 0.001). Conclusions: The mean ECD by the EBs and CIARC were similar, but there was considerable variability between determinations for individual corneas. Agreement improved between the 2 measurements when more than 100 cells were able to be analyzed.

We executed a genome-wide association scan for age-related macular degeneration (AMD) in 2,157 cases and 1,150 controls. Our results validate AMD susceptibility loci near CFH ( P < 10 −75 ), ARMS2 ( P < 10 −59 ), C2/CFB ( P < 10 −20 ), C3 ( P < 10 −9 ), and CFI ( P < 10 −6 ). We compared our top findings with the Tufts/Massachusetts General Hospital genome-wide association study of advanced AMD (821 cases, 1,709 controls) and genotyped 30 promising markers in additional individuals (up to 7,749 cases and 4,625 controls). With these data, we identified a susceptibility locus near TIMP3 (overall P = 1.1 × 10 −11 ), a metalloproteinase involved in degradation of the extracellular matrix and previously implicated in early-onset maculopathy. In addition, our data revealed strong association signals with alleles at two loci ( LIPC , P = 1.3 × 10 −7 ; CETP , P = 7.4 × 10 −7 ) that were previously associated with high-density lipoprotein cholesterol (HDL-c) levels in blood. Consistent with the hypothesis that HDL metabolism is associated with AMD pathogenesis, we also observed association with AMD of HDL-c—associated alleles near LPL ( P = 3.0 × 10 −3 ) and ABCA1 ( P = 5.6 × 10 −4 ). Multilocus analysis including all susceptibility loci showed that 329 of 331 individuals (99%) with the highest-risk genotypes were cases, and 85% of these had advanced AMD. Our studies extend the catalog of AMD associated loci, help identify individuals at high risk of disease, and provide clues about underlying cellular pathways that should eventually lead to new therapies.