Department of Ophthalmology, University of California, San Francisco, San Francisco, California.
Invest Ophthalmol Vis Sci. 2013 Aug 28;54(8):5836-47. doi: 10.1167/iovs.13-12557.
To study the relationship between cone spacing and density and clinical measures of visual function near the fovea.
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.
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.
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.
研究锥体细胞间距和密度与黄斑附近视功能临床指标的关系。
采用自适应光学扫描激光检眼镜对 26 例遗传性视网膜变性患者的光感受器嵌合体进行高分辨率成像。在黄斑中心或附近（平均[标准差]偏心度，0.02[0.03]度；最大偏心度，0.13 度）进行锥体细胞间距测量，并将其转换为 Z 分数、与各部位正常锥体细胞分数（基于 37 例年龄相似的视力正常眼）相比的低于平均值的锥体细胞百分比。将 Z 分数和低于平均值的锥体细胞百分比与最佳矫正视力（VA）和黄斑敏感性进行比较。
视力与锥体细胞间距显著相关（Spearman 秩相关 ρ=-0.60，P=0.003），尽管锥体细胞密度测量值低于正常 52%，但视力仍保持正常（≥80 个字母）。黄斑敏感性与锥体细胞间距呈显著相关（ρ=-0.47，P=0.017），尽管密度测量值比正常水平低 52%至 62%，但仍保持正常（≥35 分贝）。
在 VA 和敏感性仍在正常范围内的黄斑区或其附近，锥体细胞密度比正常水平低 62%。尽管与黄斑锥体细胞间距有显著相关性，但 VA 和敏感性并不能敏感地反映黄斑锥体细胞嵌合体的完整性。直接、客观的锥体细胞结构测量可能比 VA 或黄斑敏感性更能敏感地反映遗传性视网膜变性患者疾病的严重程度。
