Ely Amanda L, Weinstein Joel M, Price Jade M, Gillon Jason T, Boltz Marianne E, Mowery Stephen F, Aminlari Ardalan, Gilmore Rick O, Cheung Albert Y
Penn State Hershey Eye Center, Hershey, Pennsylvania, United States.
Penn State College of Medicine, Hershey, Pennsylvania, United States.
Invest Ophthalmol Vis Sci. 2014 Sep 25;55(11):7248-55. doi: 10.1167/iovs.14-15052.
To determine whether objective visual function, measured by swept-parameter visual evoked potential (sVEP), is preferentially degraded by neutral density filtration (NDF) in normal control and fellow eyes compared to amblyopic eyes, and to determine whether the response to NDF is a function of stimulus type, using grating and vernier stimuli.
Monocular Snellen acuity and both grating and vernier sVEP responses were measured in each eye of 23 children or adolescents with amblyopia and 21 visually and neurologically normal children or adolescents. Acuity and sVEP responses were measured with and without a 2.0 log unit neutral density filter before the viewing eye.
Suprathreshold sVEP grating responses were more sensitive than vernier to degradation by amblyopia in the unfiltered state and to NDF-induced preferential degradation of responses from fellow and normal control eyes. For threshold measurements, on the other hand, vernier responses were more sensitive to degradation by amblyopia in the unfiltered state and to NDF-induced preferential depression. Threshold vernier responses of amblyopic eyes were paradoxically enhanced by NDF.
Neutral density filtration causes preferential degradation of both threshold and suprathreshold sVEP responses in normal control eyes and fellow eyes of amblyopes, compared to amblyopic eyes. The degradation is stimulus specific and dependent upon whether threshold or suprathreshold responses are measured. Grating responses are more likely to identify suprathreshold abnormalities, while vernier stimuli are more likely to detect threshold abnormalities. These findings may be used to optimize the stimulus parameters and design of future studies utilizing evoked potential techniques in amblyopic subjects.
通过扫频参数视觉诱发电位（sVEP）测量客观视觉功能，确定在正常对照眼和弱视对侧眼中，中性密度滤光片（NDF）是否比弱视眼更易导致其功能退化；并使用光栅和游标刺激，确定对NDF的反应是否为刺激类型的函数。
对23名患有弱视的儿童或青少年以及21名视力和神经功能正常的儿童或青少年的每只眼睛测量单眼斯内伦视力以及光栅和游标sVEP反应。在观察眼前放置或不放置2.0对数单位中性密度滤光片的情况下测量视力和sVEP反应。
在未过滤状态下，弱视对超阈值sVEP光栅反应的影响比对侧和正常对照眼中NDF诱导的反应优先退化更为敏感。另一方面，对于阈值测量，游标反应在未过滤状态下对弱视导致的退化以及NDF诱导的优先抑制更为敏感。NDF反常地增强了弱视眼的阈值游标反应。
与弱视眼相比，中性密度滤光片会导致正常对照眼和弱视对侧眼中阈值和超阈值sVEP反应的优先退化。这种退化是刺激特异性的，并且取决于测量的是阈值反应还是超阈值反应。光栅反应更有可能识别超阈值异常，而游标刺激更有可能检测阈值异常。这些发现可用于优化刺激参数，并设计未来利用诱发电位技术研究弱视受试者的研究。
