人眼后极部视网膜光感受器细胞分布特征

目的 观察人眼后极部视网膜光感受器细胞分布特征，探讨其细胞密度随离心度变化的规律以及与视敏度的关系。 方法 取20个钻取角膜后剩余的眼杯，固定，进行视网膜铺片，用微分干涉显微镜观察后极部视网膜细胞形态和密度，首先观察光感受器细胞内节，以中央凹为始点向颞侧周边逐渐推进。 结果 视锥细胞最高密度位于中央凹，细胞密度范围134 000~267 000个/mm²，细胞平均数为198 090 个/mm²。细胞密度个体差异［CV值(标准差／均数)表示］极大，CV值为18.2%，从中央凹向外细胞密度及个体差异均迅速减少。视杆细胞高密度区约位于离心度4 mm左右，细胞密度最高值范围72 610~182 350/mm²，3~5 mm之间细胞保持高密度。 结论 光感受器细胞内节单层排列，其计数可反映细胞的绝对值。中央凹极高视锥细胞密度为提供敏锐中心视力的基础，其极大的个体差异与发育有关。视杆细胞杆体在离心度4 mm左右存在高密度带，此高密度带的存在是此处视网膜有较好暗视力的基础。

Distribution of human retinal photoreceptor cells at the posterior pole of the ocular fundus

Objective To observe the distribution of human photoreceptor cells at the posterior pole, detect the change of density of the cells affected by eccentricity, and analyze the relationship between the density distribution and the visual sensitivity. Methods Twenty human eye cups with the cornea removed were fixed in 4% polyformaldehyde for 1-4 weeks, and the retinal mounts were observed by differential interference contrast microscope to reveal the retinal cellular configuration and density. The inner segments of photoreceptor cells were first observed from the center to the temporal peripheral part of the retinal mounts. Results The highest density of visual cone cells was at the central fovea (134 000-267 000/mm², mean 198 090/mm²; CV value:18.2%). The density and individual variation decreased rapidly in the peripheral area. The high density area of rod cells was at the 4 mm of the eccentricity, with the highest value of 72 610-182 350/mm² and with the high density between 3 and 5 mm. Conclusions The inner segment of photoreceptor cells was monolayer, which may tell the cellular absolute value. The high density of retinal cone cells at the central fovea provide the basis of sensitive central visual acuity, which relates to the individual variation and development. The rod cells have the peak density at the eccentricity with 4 mm, and this area has the greatest sensitivity of dim vision.