simEye: computer-based simulation of visual perception under various eye defects using Zernike polynomials

Abstract

Abstract. We describe a computer eye model that allows for aspheric surfaces and a three-dimensional computer-based ray-tracing technique to simulate optical properties of the human eye and visual perception under various eye defects. Eye surfaces, such as the cornea, eye lens, and retina, are modeled or approximated by a set of Zernike polynomials that are fitted to input data for the respective surfaces. A ray-tracing procedure propagates light rays using Snell's law of refraction from an input object ͑e.g., digital image͒ through the eye under investigation ͑i.e., eye with defects to be modeled͒ to form a retinal image that is upside down and left-right inverted. To obtain a firstorder realistic visual perception without having to model or simulate the retina and the visual cortex, this retinal image is then backpropagated through an emmetropic eye ͑e.g., Gullstrand exact schematic eye model with no additional eye defects͒ to an output screen of the same dimensions and at the same distance from the eye as the input object. Visual perception under instances of emmetropia, regular astigmatism, irregular astigmatism, and ͑central symmetric͒ keratoconus is simulated and depicted. In addition to still images, the computer ray-tracing tool presented here ͑simEye͒ permits the production of animated movies. These developments may have scientific and educational value. This tool may facilitate the education and training of both the public, for example, patients before undergoing eye surgery, and those in the medical field, such as students and professionals. Moreover, simEye may be used as a scientific research tool to investigate optical lens systems in general and the visual perception under a variety of eye conditions and surgical procedures such as cataract surgery and laser assisted in situ keratomileusis ͑LASIK͒ in particular.

Modeling the effect of facial topographies upon the visual field of humans and primates

“…Ray tracing eye models have been developed for normal and irregular human optical conditions (Fink et al. , 1996; Fink and Mico, 2006; Tan et al. , 2008) but this is beyond the scope of the current study.…”

“…It would further require more specific ray tracing software since Cinema 4D is optimized for speed rather than accurate rendering of complex compound optical systems. Ray tracing eye models have been developed for normal and irregular human optical conditions (Fink et al, 1996;Fink and Mico, 2006;Tan et al, 2008) but this is beyond the scope of the current study.…”

Simulation of Human Eye Optical System Properties and Depth of Field Variation

“…In Wolfgang's approach [10], ray tracing is used to simulate various eye defects. It requires complex surface modeling and the refraction is calculated according to Snell's law.…”

The Individual Virtual Eye: a Computer Model for Advanced Intraocular Lens Calculation

“…[41][42][43] Fink et al simulated human optics with real ray-tracing. [44][45][46] Others carried out investigations using RRT based on measured corneal topography data. [47][48][49][50] Sarver et al also used corneal topography data and are principally capable of calculating optical components with their Visual Optics Lab* program.…”