This paper (1) reviews the fundamental limits to visual performance imposed by optical imaging and photoreceptor sampling to determine the limits to the potential gains offered by ideal corrections; (2) examines the predicted losses in vision induced by chromatic aberration, phase shifts, typical ocular aberrations, and the gains possible by correcting the monochromatic aberrations of the eye; ...

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 surface...

Background & aims: Lead poisoning is a global problem and considered to be the most important environmental disease in children. Exposure to even low amounts of lead is dangerous. Lead containing eye make ups due to the long time contact with skin and eye mucosa can lead to blood and eye symptoms. The purpose of this study was to evaluate the amount of lead in powders of kohl in Kerman. Method:...

Many individuals with acquired brain injury (ABI) report reading problems of oculomotor origin. These may include frequent loss of place, skipping of lines and difficulty shifting to the next line of print. We describe two protocols for the testing and training of reading-related eye movements in adult individuals with ABI (traumatic brain injury [TBI] and stroke with hemianopia), who experienc...

Elasmobranch fishes utilise their vision as an important source of sensory information, and a range of visual adaptations have been shown to reflect the ecological diversity of this vertebrate group. This study investigates the hypotheses that visual optics can predict differences in habitat and behaviour and that visual optics change with ontogenetic growth of the eye to maintain optical perfo...

One of the challenges facing primary health care in South Africa is the delivery of quality eye care to all South Africans. In this regard the role of the primary health care worker, as the first point of contact, is crucial. This paper reports on the problems primary health care workers experience in providing quality eye care in Region B of the Free State. Problems identified by those involve...