Sivak J G, Hildebrand T E, Lebert C G, Myshak L M, Ryall L A
Vision Res. 1986;26(11):1865-72. doi: 10.1016/0042-6989(86)90138-0.
The avian accommodative response has long been suspected of having a corneal component resulting from contraction of a limbal extension of the ciliary muscle. Efforts to confirm the existence of such a mechanism have been sporadic and the results contradictory. In addition, while the accommodative mechanism of the bird eye is commonly considered to be very effective, the effect of lenticular aging is not known. The accommodative responses of excised chicken eyes of various age, were measured by photographing changes in focal effects on incident fine parallel laser beams in response to electrical stimulation of the intraocular muscles. An opening at the posterior pole of the eye enabled the beams to exit in order to facilitate measurement of refractive change. The question of a possible corneal contribution was examined by taking advantage of the fact that corneal refractive power is neutralized when the surface of the cornea is in water. Accommodation was measured with the cornea in air and in water. The results indicate that there is little or no corneal accommodation and accommodative ability drops off substantially with age. The results may also indicate the existence of serious inter-breed differences in chicken accommodation.
长期以来，人们一直怀疑鸟类的调节反应有一个角膜成分，这是由睫状肌角膜缘延伸部的收缩引起的。证实这种机制存在的努力一直断断续续，结果相互矛盾。此外，虽然通常认为鸟眼的调节机制非常有效，但晶状体老化的影响尚不清楚。通过拍摄不同年龄的离体鸡眼在眼内肌肉电刺激下对入射细平行激光束的聚焦效应变化，来测量其调节反应。眼球后极的一个开口使光束能够射出，以便于测量屈光变化。利用角膜表面在水中时角膜屈光力被中和这一事实，研究了角膜可能产生的影响。分别在角膜处于空气和水中的情况下测量调节。结果表明，几乎没有或不存在角膜调节，并且调节能力随着年龄的增长而大幅下降。结果还可能表明，鸡的调节能力在不同品种间存在显著差异。
