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G. R. Jackson, M. G. Brigell, I. U. Scott, L. E. Walter; Comparison of Visual Function Biomarkers in Patients With Early or Intermediate AMD Versus Controls. Invest. Ophthalmol. Vis. Sci. 2010;51(13):2799.
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© ARVO (1962-2015); The Authors (2016-present)
More sensitive endpoints than visual acuity to early age-related macular degeneration (AMD) will increase the feasibility of preventative AMD clinical trials. We report baseline data of an ongoing 1-year natural history study of visual function in patients with early to intermediate AMD and age-matched controls. The primary goal is to identify visual function endpoints that are more sensitive than visual acuity to early AMD progression.
Six aspects of visual function were measured: acuity (E-EDTRS), low-luminance visual acuity (1.7 cd/m2 ETDRS chart), SKILL card acuity, contrast sensitivity (Pelli-Robson), rod-mediated dark adaptation (AdaptRx), and photostress (slit lamp and 1.7 cd/m2 ETDRS chart). Three-field stereoscopic fundus photographs were taken for future grading.
The sample includes 33 participants with early to intermediate AMD and 14 healthy controls. At baseline, the AMD group exhibited similar visual acuity (80 letters) to the control group (83 letters) (p=0.14). Compared to the control group, the AMD group demonstrated a mean reduction in low luminance acuity of 5.5 letters (p = 0.0022), mean reduction in SKILL card acuity score of 9 letters (p = 0.0015), mean reduction in contrast sensitivity of 2.7 letters (p = 0.0008), mean increase of 14 minutes to reach the rod intercept for rod-mediated dark adaptation (p < 0.0001), and a mean increase of 4.2 minutes to recover to baseline for photostress (p < 0.0001).
The AMD group exhibited greater visual dysfunction on 5 of the 6 vision tests; only visual acuity was similar between the two groups. Dark adaptation and photostress, which measure retinal adaptation, were more sensitive to early to intermediate AMD than steady state tests such as low luminance visual acuity, SKILL card acuity, or contrast sensitivity. Dark adaptation exhibited the highest sensitivity to early AMD (91%) followed by photostress (75%). Static visual function measurements ranged in sensitivity from 24% for visual acuity to 47% for SKILL card acuity. Participants’ vision will be assessed at 6 and 12 months to evaluate progression of visual dysfunction and its relationship to funduscopic evidence of AMD progression.
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