Relationship between foveal cone structure and clinical measures of visual function in patients with inherited retinal degenerations. Invest Ophthalmol Vis Sci 2013 Aug 28;54(8):5836-47
Date
08/03/2013Pubmed ID
23908179Pubmed Central ID
PMC3757906DOI
10.1167/iovs.13-12557Scopus ID
2-s2.0-84883233403 (requires institutional sign-in at Scopus site) 100 CitationsAbstract
PURPOSE: To study the relationship between cone spacing and density and clinical measures of visual function near the fovea.
METHODS: High-resolution images of the photoreceptor mosaic were obtained with adaptive optics scanning laser ophthalmoscopy from 26 patients with inherited retinal degenerations. Cone spacing measures were made close to or at the foveal center (mean [SD] eccentricity, 0.02 [0.03] degree; maximum eccentricity, 0.13 degree) and were converted to Z-scores, fraction of cones, and percentage-of-cones-below-average compared with normal values for each location (based on 37 age-similar visually normal eyes). Z-scores and percentage of cones below average were compared with best-corrected visual acuity (VA) and foveal sensitivity.
RESULTS: Visual acuity was significantly correlated with cone spacing (Spearman rank correlation ρ = -0.60, P = 0.003) and was preserved (≥ 80 letters), despite cone density measures that were 52% below normal. Foveal sensitivity showed significant correlation with cone spacing (ρ = -0.47, P = 0.017) and remained normal (≥ 35 decibels), despite density measures that were approximately 52% to 62% below normal.
CONCLUSIONS: Cone density was reduced by up to 62% below normal at or near the fovea in eyes with VA and sensitivity that remained within normal limits. Despite a significant correlation with foveal cone spacing, VA and sensitivity are insensitive indicators of the integrity of the foveal cone mosaic. Direct, objective measures of cone structure may be more sensitive indicators of disease severity than VA or foveal sensitivity in eyes with inherited retinal degenerations.
Author List
Ratnam K, Carroll J, Porco TC, Duncan JL, Roorda AAuthor
Joseph J. Carroll PhD Director, Professor in the Ophthalmology and Visual Sciences department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
AdolescentAdult
Female
Fovea Centralis
Humans
Male
Middle Aged
Retinal Cone Photoreceptor Cells
Retinal Degeneration
Sensory Thresholds
Visual Acuity
Young Adult
