Suttle Catherine M, Turner Anne M
School of Optometry and Vision Science, University of New South Wales, Sydney, NSW 2052, Australia.
Ophthalmic Physiol Opt. 2004 Mar;24(2):91-9. doi: 10.1046/j.1475-1313.2003.00174.x.
Visual acuity and contrast sensitivity are lower in children with Down's syndrome than in those developing normally. In many cases, this difference might be accounted for by the relatively high incidence of ocular abnormalities (including refractive error and strabismus) in Down's syndrome. However, abnormal spatial vision persists in children with Down's syndrome in the absence of ocular abnormality, suggesting that abnormal retino-cortical visual processing explains reduced visual function in this group. The aim of the present study was to assess retino-cortical function in children with Down's syndrome by recording transient visual evoked potentials (VEPs) in response to pattern stimuli. Responses from children with Down's syndrome were compared with those recorded from children developing normally. Response latency is similar in the two groups, but morphology differs, with the N75 component being clearly present in the normal responses, but diminished or undetectable in responses from children with Down's syndrome. Our findings may suggest a cortical abnormality specific to the source of the N75 component of pattern-reversal achromatic VEPs.
唐氏综合征患儿的视力和对比敏感度低于正常发育的儿童。在许多情况下，这种差异可能是由于唐氏综合征患儿眼部异常（包括屈光不正和斜视）的发生率相对较高。然而，在没有眼部异常的唐氏综合征患儿中，空间视觉异常仍然存在，这表明视网膜 - 皮质视觉处理异常解释了该群体视觉功能的降低。本研究的目的是通过记录对图案刺激的瞬态视觉诱发电位（VEP）来评估唐氏综合征患儿的视网膜 - 皮质功能。将唐氏综合征患儿的反应与正常发育儿童记录的反应进行比较。两组的反应潜伏期相似，但形态不同，正常反应中N75成分明显存在，而唐氏综合征患儿的反应中该成分减弱或无法检测到。我们的研究结果可能表明，图案反转消色差VEP的N75成分来源存在特定的皮质异常。
