浅谈《调节机制新概念:基于超焦距-微变焦的人眼光学系统》

摘要

调节是指人眼在看清近处物体时晶状体屈光能力发生改变的现象.《调节机制新概念:基于超焦距-微变焦的人眼光学系统》一文引入了摄影镜头的超焦距概念,并基于超焦距的特点,提出人眼实际上存在3个超焦距,即远超焦距、近超焦距和调节超焦距.在调节活动中,睫状肌的收缩是推压悬韧带、悬韧带推压晶状体赤道部,还是使拉紧的悬韧带松弛、晶状体前突,这对于理解《调节机制新概念:基于超焦距-微变焦的人眼光学系统》是至关重要的.从解剖结构上来讲,在调节活动中,睫状肌的收缩推压悬韧带、纤弱的悬韧带推压晶状体赤道部的可能性较小,而使拉紧的悬韧带松弛、晶状体前突的可能性更大.笔者认为,睫状肌的收缩在调节活动中具有主动性的启动作用,因此当眼从视近转向视远时,睫状肌(收缩的环形肌)将会迅即恢复到松弛常态,晶状体受悬韧带的牵拉而恢复到原来的相对扁平状,并非被动性压迫,因为晶状体并不是调节活动的启动体,只不过是一个承载体而已.人眼的调节活动是非常复杂的,在整个调节活动中,不仅有睫状肌的收缩、晶状体屈光能力的增加,也伴随着瞳孔的缩小和集合的发生,因此任何机械、单一的模式者很难解释人眼复杂的调节活动.%Accommodation is a phenomenon that crystalline lens change its refractive power when human eyes see the near objects clearly.The article of A brief talk on ‘ A novel concept of accommodation:Human eyes optical system based on hyperfocal distance-micro zoom'.written by Luo Fu-ming introduces a concept of hyperfocal distance from the camera.Based on the characteristic of hyperfocal distance,the author proposes that there are actually three kinds of hyperfocal distances in human eyes:far-hyperfocal distance,near-hyperfocal distance and accommodative hyperfocal distance.It is important to understand this article that whether the ciliary muscles contract to push the zonules in accommodation,and then the zonules are forced to push the lens equator,or the ciliary muscles contract to relax the tensional zonules,then the posterior surface of the lens moves forward.In view of the anatomic structure,the possibility that the ciliary muscles contract to push the zonule and then the slim zonules push the lens equator is less than that the ciliary muscles contract to relax the tensional zonules and then the posterior surface of the lens moves forward in accommodation.In my opinion,the contraction of the ciliary muscles would startup actively in accommodation.So when the eyes transfer from near vision to distance vision,the ciliary muscles (contracting circular muscles) will return to the relaxed normal state immediately.The crystalline lens will immediately recover to its original relatively flatten state by traction of the zonules,rather than passive compression.Because the crystalline lens is not the startup body but a supporting body in accommodation.The accommodation of human eye is very complicated.During the whole process of accommodation,there are not only contraction of ciliary muscles and increase of refractive power in crystalline lens,but also accompanied reaction of miosis and convergence.So it is difficult to explain the complex activity of human eyes using any extreme,mechanical and single mode.