A brief talk on ‘ A novel concept of accommodation : Human eyes optical system based on hyperfocal distance-micro zoom ' / 中华实验眼科杂志

ABSTRACT

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 accommodationHuman 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 eyesfar-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.