Study On The Ocular Wavefront Aberrations And The Customized Corrections

Human eye, similar to the optical system, owns optical aberrations. Visual symptoms will be possibly caused from the alteration of the ocular aberrations.The cornea is not only the main element of the ocular refractive system, but also the site of laser refractive surgery. Research on the corneal wavefront aberrations (WFAs) is therefore become important for the improvement of laser refractive surgery. The measurement and correction of the ocular WFAs of the human eye, particularly those of the corneal aberrations were studied in this paper. The relationship between the corneal WFAs and related influencing factors, such as corneal asphericity, apical radius, size and position of the entrance pupil, was presented. The alteration of corneal shape due to laser refractive surgery and subsequent changes of the corneal WFAs were studied. The surgically induced increment of corneal asphericity was the most important factor for the introduction of the additional corneal aberration. The quantitative relation between corneal asphericity and the profile of laser corneal ablation was determined and the control of corneal aberration based on the aspheric laser ablation profile was deduced theoretically, which will help to develop more rational customized algorithm for laser refractive surgery.The novel customized laser refractive surgery based on the corneal WFAs and asphericity was developed and studied, and the clinical evaluation was also performed. The results demonstrated that less increase of postoperative corneal WFAs was induced and the postoperative visual quality was further improved in the customized surgery than in the conventional one. Ocular WFAs analysis has various important applications in ophthalmology. A kind of novel analytical system was developed and presented in this paper. The objective measurement and subjective refinement are combined in this system using the closed-loop between Harmann-Shack wavefront sensor and the microfabricated membrane deformable mirror. The special aberration could be generated with the control of the deformable mirror. The optimum visual perception of the target could be realized with the subjective adjustment of the wavefront.The safe, convenient, cost-effective customized laser correction for the ocular aberrations and the novel close-loop ocular WFAs analytical system for the applications in the basic research, clinical analysis of ocular WFAs were provided in this study. This study provides a novel customized laser refractive correction which helps to improve the posterative visual quality, and will lead to further research in aberration-free visual refractive system and super-normal vision.