First Author: Y.C.Yang UK
Co Author(s): E.H. Souied N. Narendran P. Margaron R. Hashmonay J. Warburton 0 0 0 0 0 0 0 0 0
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To investigate the impact of reducing central retinal thickness (CRT) on best corrected visual acuity (VA) and the relationship between CRT and VA gain in ranibizumab (RBZ) recipients with wet age-related macular degeneration who completed the 12-month EXCITE study.
The EXCITE study was a prospective, multicenter clinical trial that investigated different treatment regimens of RBZ in patients with wet AMD.
Data from completers of the 12-month study were analyzed. CRT and VA data from all patients (n=275) or a subgroup with baseline CRT ≥275μm (n=179) treated monthly with 0.3 mg or quarterly with 0.3 or 0.5 mg RBZ were used. A linear regression model was used to describe the relationship between CRT and VA at month 12 (M12), or VA gain between baseline and M12, or between CRT and VA changes between baseline and M12. Patients were divided into five 50-μm strata of CRT at M12. Within each stratum, CRT change was determined and examined against VA gain.
No relationship between CRT and VA or VA gain at M12, or change in CRT and VA between baseline and M12 (R2<0.05) was observed. Further stratified analysis showed that CRT at M12 an inversely proportional response between CRT at M12 and improvement in CRT between baseline and M12 (from a median reduction of 127μm for CRT ≤150μm to a 32μm increase for CRT >300μm). In contrast VA gain was the highest (median=8 ETDRS letters) for the intermediate stratum 200-250μm, compared with a median VA gain of 6 letters for the thinnest retina (CRT ≤150μm) and 3 letters for the thickest retina (CRT >300μm) at M12. This effect was also seen when the analysis was restricted to the subgroup with a high baseline CRT ≥275μm. Reduction in CRT at M12 was more pronounced in all strata for this subgroup, especially for the thinnest retina, and also inversely correlated with CRT at M12 (median reduction of 214, 172, 125, 76, and 2μm for CRT ≤150μm, 150μm
No linear correlation was found between VA gain and CRT at M12. Further stratified analysis indicated that CRT reduction with ranibizumab up to a threshold was associated with improved VA gain; further retinal thinning did not translate into additional VA gain.