Optical impact of correcting elements

Resumen

Correcting elements such as intraocular lenses (IOL) and contact lenses (CL) are commonly used in ophthalmology in order to correct refractive errors, presbyopia and cataract. Thus, these optical elements are in the center of scientific research and development. The optical impact of these elements is the main subject of this Doctoral Thesis. The optical impact refers to the optical results that these elements induce in the optical system of the human eye. The visual impact is also simulated and calculated in order to find the differences between the optical and the visual quality of a human eye model with correcting elements. Thus, then present Thesis is about developing models using simulations in a computer-programming environment to address the optical and visual impact of optical elements applied in elderly-related disabilities and to propose alternatives to current approaches. All the designs in this Thesis are about IOLs and CLs that are designed following general characteristics and not specific guidelines of a patent or an element that is copyrighted. In the first chapter, there is a general introduction of the topic. There is information about the human eye biology and its different parts. There is a description of the accommodation function and how is affected by presbyopia. In the end there are listed some methods of correction of the presbyopic effects, such as IOLs and CLs. There is also a short description about the human eye models in general. In the second chapter, there is a comparative study about human eye models that are used in vision sciences. In this chapter, a comparison between three theoretical eye models is done, the Navarro, the Arizona and the Liou-Brennan eye models. The comparison is about the ability of these models to simulate accommodation and if the results that they produce are the same or if there are differences and where these differences are due to. In the third chapter, there is a study about the dioptric power distribution between the anterior and posterior surfaces of a monofocal IOL. In this chapter is tested whether the anterior or the posterior surface of an IOL is optimal to carry the largest amount of dioptric power of the IOL. It is also tested on which of the two surfaces the asphericities of an aspheric IOL have to be designed for better optical quality. In the fourth chapter, a study about optical and visual results is taking place. The study is about monofocal IOLs that are designed in customized (personalized) human eye models. The customization is on the anterior corneal surface that is altered with topographic data from real patients. The IOLs are combined with CLs designs and their designs are either optimized or non-optimized, in order to test the difference between their impacts. There is also a study of different misalignments such as decentrations and tilts, in order to test the tolerance of the designs in such conditions. In the fifth chapter, there is a continuation of the previous study. Diffractive bifocal IOLs are designed in the same group of personalized human eye models and the optical and visual results are compared. The IOLs are tested without the combination of CLs in this study. There is also a comparison of different misalignments (decentrations and tilts) in order to compare the designs’ tolerance in such conditions for far and near target distances. And finally in the sixth chapter, an intraocular telescopic system is designed with different positioning in the eye model. The position of the telescope changes the optical and visual results produced. There is also a misalignment comparison between the designs that tests the image projection quality on the retinal plane of the model.