黄斑中心凹光感受器局部缺损对视力的影响

Effects of local foveal photoreceptor defect on visual acuity

目的 观察黄斑中心凹光感受器局部缺损对视力的影响。方法 经频域光相干断层扫描（SD-OCT）检查发现黄斑中心凹光感受器局部缺损的患者（光感受器局部缺损组）31例31只眼和年龄、屈光度匹配的正常人（正常对照组）30名30只眼纳入研究。光感受器局部缺损组31只眼中，黄斑中心凹光感受器全层缺损22只眼（全层缺损组），光感受器外节缺损9只眼（外节缺损组）。所有受检者均行最佳矫正视力（BCVA）、裂隙灯显微镜、直接检眼镜和SD-OCT检查。独立样本t检验比较光感受器局部缺损组与正常对照组之间平均黄斑区中心凹视网膜厚度（CFT）之间的差异；光感受器内外节全层缺损和外节缺损患者平均最小分辨角对数视力（logMAR）BCVA、平均CFT、平均光感受器缺损最大宽度、平均缺损面积、平均光感受器缺损最大高度及平均残余视网膜厚度之间的差异。结果 光感受器局部缺损组、正常对照组平均CFT分别为（225.32±19.70）、（240.02±10.70） μm，两组平均CFT比较，差异无统计学差异（t=-1.96，P＞0.05）。全层缺损组、外节缺损组平均logMAR BCVA分别为0.22±0.31、0.32±0.43；平均CFT分别为（224.09±20.57）、（228.33±18.17） μm；平均光感受器缺损最大宽度分别为（131.32±108.18）、（143.22±66.93） μm；平均缺损面积分别为（0.022±0.054）、（0.019±0.019）mm2；平均光感受器缺损最大高度分别为（77.41±6.62）、（44.89±4.26） μm；平均残余视网膜厚度分别为（87.00±20.31）、（128.33±23.54） μm。两组患者在平均logMAR BCVA、平均CFT、光感受器缺损最大宽度、缺损面积之间比较，差异无统计学意义（t=-0.76、-0.538、-0.305、0.166，P＞0.05）；平均光感受器缺损最大高度、平均残余视网膜厚度之间比较，差异有统计学意义（t=12.72、-4.91，P＜0.05）。光感受器缺损最大宽度、缺损面积与BCVA呈负相关（t=-0.529、-0.494，P＜0.05）。结论 黄斑中心凹光感受器局部缺损可造成视力下降，缺损范围越大，视力下降越明显。

Objective To observe the effects of local macular foveal photoreceptor defects on visual acuity.Methods Thirty-one patients （31 eyes） with photoreceptor defect in macular fovea （case group） diagnosed by spectral domain optical coherence tomography （SD-OCT） and 30 patients （30 eyes） age- and diopter- matched normal subjects （control group） were enrolled in this study. There were 22 eyes with full photoreceptor defects and 9 eyes with outer segment defects in case group. All subjects were examined for best corrected visual acuity （BCVA）, slit-lamp microscopy, direct ophthalmoscope and SD-OCT. Independent sample t-test was used to compare central foveal thickness （CFT） between case group and control group. Difference of logMAR BCVA, CFT, maximum width and height of photoreceptor defects, defected area and residual retinal thickness in macular between patients with full photoreceptor defects and outer segment defects were also compared.Results The CFT of case group and control group were （225.32±19.70）,（240.02±10.70） μm, the difference was not statistically significant （t=-1.96, P〉0.05）. In full photoreceptor defects and outer segment defects patients, the mean logMAR BCVA were 0.22±0.31, 0.32±0.43; the mean CFT were （224.09±20.57）, （228.33±18.17） μm; the maximum width of photoreceptor defects were （131.32±108.18）, （143.22±66.93） μm; the mean defected area were （0.022±0.054）, （0.019±0.019） mm2; the mean maximum height of photoreceptor defects were （77.41±6.62）, （44.89±4.26） μm; the mean residual retinal thickness were （87.00±20.31）, （128.33±23.54） μm respectively. There was no statistical significance between full photoreceptor defects and outer segment defects patients in the mean logMAR BCVA, CFT, maximum width of photoreceptor defects and defected area （t=-0.76, -0.538, -0.305, 0.166; P〉0.05）, but there were significant difference in mean maximum width of photoreceptor defects and residual retinal thickness （t=12.72, -4.91;P〈0.05）. Conclusions The local photoreceptor defects in macular fovea can lead to decrease of visual acuity. The wider the photoreceptor defects, the worse the visual acuity.