Optical modelling of ocular parameters in eyes of varying refractive errors

This study used optical modelling to investigate ocular parameters in eye with varying refractive states and also explored accommodation. Three different lens models were used: equivalent refractive index lens, shell lens, and gradient index lens. The study also investigated the impact of various eye parameters, such as corneal radius (CRC), axial length (AL), lens refractive index, and lens thickness, on refractive errors and accommodation. Refractive error maps were conducted, and the axial length and corneal radius (AL/CRC) ratio were investigated.

Eye models not intended for simulating refractive errors may be used for small ray incident angles. High refractive errors change almost linearly, while with low refractive errors (from -2 D to +2 D), results depend on the simulation method and the models used. A comparative analysis between the eye models and the literature data, shows that eye models do not behave in the same way with parameters from different ethnic groups. This indicates the need for a new approach to modelling, as there is a lack of eye models for different ethnicities. Additional simulations of AL/CRC and refractive error maps were conducted. These two parameters with refractive error maps provide more information about the similarities between different groups, such as age, sex, or ethnicity, than just the AL/CRC ratio. This information can help control the potential risk of refractive error changes for both groups and individuals as it can predict the development of refractive error.