Sensitivity Loss in Early Glaucoma Can Be Mapped to an Enlargement of the Area of Complete Spatial Summation
Sensitivity Loss in Early Glaucoma Can Be Mapped to an Enlargement of the Area of Complete Spatial Summation
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DOI：
10.1167/iovs.10-5718
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发表时间：
2010-12-01
影响因子：
4.4
通讯作者：
Anderson, Roger S.
中科院分区：
文献类型：
--
作者：
Redmond, Tony;Garway-Heath, David F.;Anderson, Roger S.
目的。完全空间和面积（Ricco’s area）是在阈值处面积x强度恒定时的最大刺激尺寸。作者试图研究早期青光眼的Ricco面积变化是否可以解释伴随视网膜神经节细胞丢失的视觉信噪比下降。在消色差和s锥隔离条件下，测量24例早期青光眼患者（测试位置的总偏差平均值为-1.3 dB，范围为+2 dB至-8 dB）和26例年龄相近的健康受试者的4 10个视网膜位置的空间求和函数，并测定Ricco’s面积。在相同位置测量消色差光栅分辨率，以估计功能神经节细胞密度。消色差（上视野扩大0.57 log单位，P < 0.01；下视野扩大0.72 log单位，P < 0.01）和色差（上视野扩大0.26 log单位，P < 0.01；下视野扩大0.25 log单位，P = 0.065）刺激下，患者的Ricco面积均比对照组增大，沿强度轴的垂直叠加曲线移动可忽略。青光眼患者两半视野的分辨力明显降低（P < 0.001）。Ricco’s面积与分辨率之间存在微弱但显著的关系。在早期青光眼中，里氏区的扩大完全补偿了周围视敏度的降低，以维持里氏区的恒定阈值，提示神经节细胞损失时信号池的增加。空间和曲线向右的位移表明，周边刺激应该能够调节大小和/而不是对比度，这可能会增强测量噪声内的青光眼信号。（中国眼科杂志，2010;51:6540-6548）DOI:10.1167/iovs.10-5718
PURPOSE. The area of complete spatial summation (Ricco's area) is the largest stimulus size for which area x intensity is constant at threshold. The authors sought to investigate whether Ricco's area changes in early glaucoma to account for the decreased visual signal/noise ratio that may accompany retinal ganglion cell loss.METHODS. Spatial summation functions were measured, and Ricco's area was determined at four 10 retinal locations in 24 patients with early glaucoma (total deviation at test locations, mean, -1.3 dB; range, +2 dB to -8 dB) and 26 age-similar healthy subjects under achromatic and S-cone isolation conditions. Achromatic grating resolution acuity was measured at the same locations to estimate functional ganglion cell density.RESULTS. Ricco's area was enlarged in patients compared with controls for both achromatic (enlarged by: superior field, 0.57 log units, P < 0.01; inferior field, 0.72 log units, P < 0.01) and chromatic (enlarged by: superior field, 0.26 log units, P < 0.01; inferior field, 0.25 log units, P = 0.065) stimuli, with negligible vertical summation curve shifts along the intensity axis. Resolution acuity was significantly reduced in glaucoma patients in both hemifields (P < 0.001). There was a weak, but significant, relationship between Ricco's area and resolution acuity.CONCLUSIONS. Enlargement of Ricco's area completely compensates for reduced perimetric sensitivity in early glaucoma to maintain constant threshold at Ricco's area, suggesting an increase in signal pooling in response to ganglion cell loss. The rightward displacement of the spatial summation curve indicates that perimetric stimuli should be capable of modulating in size as well as/instead of contrast, which may boost the glaucoma signal within measurement noise. (Invest Ophthalmol Vis Sci. 2010; 51: 6540-6548) DOI:10.1167/iovs.10-5718