Jaworski Alexandra, Gentle Alex, Zele Andrew J, Vingrys Algis J, McBrien Neville A
Department of Optometry and Vision Sciences, The University of Melbourne, Victoria, Australia.
Invest Ophthalmol Vis Sci. 2006 Aug;47(8):3695-702. doi: 10.1167/iovs.05-1569.
The present study investigated retinal integrity in high myopia using spatial psychophysical tasks.
Ten axial high myopes (-8.5 to -11.5 D) and 10 age-matched control subjects (+/-1.0 D) were recruited. All participants underwent clinical examination and ocular biometry and demonstrated no visible macular disease with visual acuities better than 6/12. Foveal summation thresholds were determined for white and S-cone-isolating spots of various diameters up to 5.4 degrees and spatial contrast sensitivity to luminance sine wave gratings (0.5-9.7 cyc/deg). Data were analyzed after correction for the magnification induced by eye size and correcting lens power.
Spatial summation for both white and S-cone-isolating spots showed a generalized loss of sensitivity at all spot sizes in myopes relative to control subjects (P = 0.01). Critical areas at maximum summation were significantly larger in myopes, for S-cone isolating spots only, after image size correction (P = 0.048). Sensitivity at maximum summation correlated negatively with vitreous chamber depth for both targets (P = 0.005). Sensitivities for S-cone and luminance spots also correlated (P < 0.001), indicating widespread dysfunction. Myopes displayed contrast sensitivity losses at high spatial frequencies (P </= 0.006) with a normal peak contrast sensitivity.
These data can be interpreted to indicate that highly myopic eyes have either (1) a reduction in the number of receptors and/or a reduction in their sensitivity or, (2) a reduction in the sensitivity of postreceptoral processes. The presence of normal contrast sensitivity at low spatial frequencies indicates dysfunction at a postreceptoral level in high myopes.
本研究使用空间心理物理学任务调查高度近视患者的视网膜完整性。
招募了10名轴性高度近视患者（-8.5至-11.5 D）和10名年龄匹配的对照受试者（±1.0 D）。所有参与者均接受了临床检查和眼部生物测量，且黄斑部无可见病变，视力优于6/12。测定了直径达5.4度的各种白色和S视锥细胞分离点的中央凹总和阈值，以及对亮度正弦波光栅（0.5 - 9.7周/度）的空间对比敏感度。在对眼大小和矫正镜片度数引起的放大率进行校正后对数据进行分析。
与对照受试者相比，近视患者中白色和S视锥细胞分离点的空间总和在所有点大小下均显示出普遍的敏感度丧失（P = 0.01）。仅对于S视锥细胞分离点，在图像大小校正后，近视患者最大总和时的临界区域显著更大（P = 0.048）。两个目标在最大总和时的敏感度均与玻璃体腔深度呈负相关（P = 0.005）。S视锥细胞和亮度点的敏感度也具有相关性（P < 0.001），表明存在广泛的功能障碍。近视患者在高空间频率下显示对比敏感度损失（P ≤ 0.006），而峰值对比敏感度正常。
这些数据可以解释为表明高度近视眼要么（1）感受器数量减少和/或其敏感度降低，要么（2）感受器后过程的敏感度降低。低空间频率下正常对比敏感度的存在表明高度近视患者在感受器后水平存在功能障碍。
