Mechanical Design For Compensate The Lower-order Wave Aberrations Of The Human Eye

Some serious disease-such as Diabetes, kidney disease, tumor-can be detected by fundus detection of the human eyes.However, the human eye is not a perfect optical system, even the normal one. It has not only the Lower-order wave aberrations such as defocus and astigmatic but also some higher-order wave aberrations. The imaging quality of commonly used fundus examination equipment was not good enough because of those wave aberrations. Adaptive optical system can solve the problem, but if those aberrations were more than1.5μm, may lead to a decrease of the quality of imaging. Actually more than90%of the human eye aberration was Lower-order wave aberrations.The quality of imaging can be improved if the Lower-order wave aberrations were compensated.For compensate of the defocus, a new type of lens-liquid zoom lens were used. The step of the mechanism was0.2diopter, then find out the relationship between the focal length with the rotation angle of the outer ring, established a transmission ratio of40by worm gear adjusting mechanism.So the step was18.4degree on the worm, the error is less than0.1diopter, the residual defocus is less than0.7μm. Process the mechanism out according to the limitation of the adaptive optics system of the human eye in the geometric space,and test it,the result shows that the mechanism works well.To make the liquid crystal adaptive optics system has a wider scope, this investigation statistics the human eye astigmatic distribution range frist.find out that the astigmatism diopter were mostly in-0.25～1.5. a small number of people were more than-3.0diopter.The PV number-0.25diopter cylinder lens is less than1.5μm, so we needn’t compensate it. Then decide the lens that were used frequently-0.5diopter,-0.75diopter,-1.0diopter,-1.25diopter,-1.50diopter and-1.75diopter.For tester who has the astigmatism diopter higher than-1.75diopter,we have another slot.All the lens used for compensate astigmatic were connected to a turnplate, so the lens can be switched by Rotat the turnplate.Finally, through the above content, two machines should be designed to compensate the Lower-order wave aberrations of the human eye, and then test them. The result shows that the two machines works well, so they can provide effective service to Adaptive Imaging System of the human eyes.