Publication Date



Open access

Embargo Period


Degree Type


Degree Name

Doctor of Philosophy (PHD)


Biomedical Engineering (Engineering)

Date of Defense


First Committee Member

Fabrice Manns

Second Committee Member

Jean-Marie Parel

Third Committee Member

Sonia H. Yoo

Fourth Committee Member

Jorge Bohorquez

Fifth Committee Member

Noel Ziebarth

Sixth Committee Member

Arthur Ho


The human crystalline lens is a complex and intricate structure that continuously grows throughout our lifetime. The crystalline lens has a non-uniform distribution of protein concentrations which produces an optical gradient within the lens in both the optical and equatorial axes. This gradient refractive index is a unique property of the crystalline lens that significantly contributes to its optical power and aberrations. The objective of this dissertation is to gain a better understanding of the relationship between the crystalline lens shape, its non-uniform gradient refractive index, the lens optical power and aberrations, and their changes with accommodation and age. The information acquired in this dissertation will be used to optimize vision correction procedures and to develop a more accurate lens model to predict the power and aberrations of the whole eye. The studies of this project include establishing techniques to quantify the gradient’s contribution to the accommodative amplitude, measuring the optical power and spherical aberration of the lens using laser ray tracing, and developing an enhanced laser ray tracing system which allows for on-axis and off-axis measurements of power and 2-D wavefront aberration maps of the crystalline lens.


optics; spherical aberration; peripheral defocus; accommodation; presbyopia