Horton J C, Hocking D R
Beckman Vision Center, University of California, San Francisco 94143-0730, USA.
Vis Neurosci. 1996 Jul-Aug;13(4):787-95. doi: 10.1017/s0952523800008658.
Previous experiments in animals have shown that early unilateral eyelid suture, a model of amblyopia induced by cataract, causes shrinkage of ocular dominance columns serving the deprived eye in the striate cortex. It is unknown whether the ocular dominance columns are affected in amblyopia produced by strabismus. We examined specimens of striate cortex obtained postmortem from a 79-year-old woman with a history of amblyopia in her left eye (20/800) since age 2 from accommodative esotropia. Four years prior to her death, she suffered an ischemic infarct of the left optic disc. This injury to the left optic disc made it possible to label the ocular dominance columns using cytochrome oxidase histochemistry. The pattern of ocular dominance columns was reconstructed throughout most of the right striate cortex. No shrinkage of columns was found. In the left cortex only half the column mosaic was labelled, because the patient had some residual vision in the temporal retina of her left eye. The columns within the labelled portion of the overall mosaic appeared normal. These findings indicate that shrinkage of ocular dominance columns does not occur in humans with amblyopia caused by accommodative esotropia. The ocular dominance columns are probably no longer susceptible to shrinkage at the age when most children with this condition begin to develop amblyopia.
以往的动物实验表明，早期单侧眼睑缝合这一由白内障诱发弱视的模型，会导致纹状皮质中为被剥夺眼服务的眼优势柱缩小。尚不清楚斜视所致弱视中眼优势柱是否会受到影响。我们检查了一名79岁女性的死后纹状皮质标本，该女性自2岁起因调节性内斜视导致左眼弱视（视力20/800）。在她去世前四年，她的左眼视盘发生了缺血性梗死。左眼视盘的这种损伤使得利用细胞色素氧化酶组织化学标记眼优势柱成为可能。我们重建了大部分右侧纹状皮质的眼优势柱模式。未发现柱缩小。在左侧皮质中，只有一半的柱镶嵌被标记，因为患者左眼颞侧视网膜仍有一些残余视力。整个镶嵌标记部分内的柱看起来正常。这些发现表明，调节性内斜视所致弱视患者的眼优势柱不会缩小。在大多数患有这种疾病的儿童开始出现弱视的年龄，眼优势柱可能不再容易缩小。
