Simulation Study of the Visual Errors for Individualized Phakic and Pseudophakic eyes

Abstract

For over two decades, analytical formulas rooted in Gaussian optics have been the conventional method for determining intraocular lens (IOL) refractive power and positioning during cataract surgery. These formulas gained popularity due to their simplicity and widespread acceptance, yielding satisfactory clinical outcomes globally. Since the 1990s, wavefront analysis has also been employed in ophthalmology to assess high-order aberrations in the human eye postoperatively. Unlike low-order aberrations, such as spherical aberration, high-order optical aberrations cannot be accurately replicated by spherical surfaces, which are the basis of analytical formulas. Consequently, calculations based solely on spherical approximations do not provide a fully personalized description of the eye. Advancements in ophthalmic equipment have now made it feasible to characterize human corneal surface profiles. Corneal tomography allows for the measurement of anterior and posterior corneal surface heights at a micron scale. These detailed measurements enable the characterization of high-order components within the cornea that were previously inaccessible. Despite these technological strides, certain photic effects in both natural (phakic) and surgically altered (pseudophakic) eyes remain challenging to measure experimentally. Therefore, ray tracing simulations have become essential tools for studying these phenomena. Ray tracing, a longstanding technique in optical design, involves complex calculations based on Snell’s law to accurately predict light refraction. In contrast to Gaussian optics, ray tracing excels in non-paraxial scenarios, offering more precise results. While not yet standardized, the combination of corneal surface profile data and ray tracing methodologies allows for the simulation of fully personalized models that encompass wavefront errors and visual artifacts specific to individual eyes. In summary, while Gaussian optics have historically guided IOL power calculations, recent advancements in raytracing simulations, wavefront analysis and tomography are revolutionizing ophthalmic practices. These innovations enable a deeper understanding and more personalized approach to correcting visual aberrations, thereby enhancing clinical outcomes and patient satisfaction in ophthalmology.