Johannes J Vos

Spectral transmission of the human ocular media.

Abstract The existing literature on transmission of the human ocular media in the visible region is reviewed. Added is an ocular density curve derived from the CIE scotopic sensitivity function and the absorption curve of human rhodopsin. This ocular density curve fits the literature data very well and can serve as the transmission curve of a standard observer. The extent of individual differences in ocular density is calculated to be ±25 per cent of the average density values.

Thermal cataract, from furnaces to lasers

Background: Thermal cataract has long been known as an occupational disease in furnace workers. This affliction has virtually disappeared in western countries due to improved working conditions. However, new light sources have appeared on the scene, in particular lasers, which might also be capable of producing thermal cataract. The aim of this survey is to review the history and describe the present state of knowledge.

Depth in colour, a history of a chapter in physiologie optique amusante.

Two centuries ago, Goethe wrote in his Farbenlehre about blue as a receding colour, against yellow/red as a colour ‘piercing into the organ’. Though any verification of these psychological attributes seems to be absent, this depth effect in colour still seems to be taken for granted in art history. In visual science, the completely different and far better documented colour stereoscopic effect, known as chromostereopsis, prevails. A historical account is given of the development of ideas about this chromostereopsis, often by amusing trials and errors. The original explanation by Bruecke in terms of chromatic aberration (in present‐day literature usually indicated as transverse chromatic aberration) and a temporal off‐axis position of the fovea still forms the basis of present‐day understanding, even though Bruecke rejected his own explanation. It had to be complemented by an additional off‐axis effect of the pupil, not in an anatomical sense, as Einthoven presumed but failed to find but in a functional sense by a non‐centric Stiles‐Crawford effect. Although a comprehensive individual experimental proof is still missing, the evidence available indicates that a satisfactory quantitative explanation has been reached.

Retinal damage by optical radiation. An alternative to current, ACGIH-inspired guidelines.

Background: The ACGIH guidelines for protection against retinal damage by optical radiation are often difficult to apply due to their lack of transparency. The less known guidelines by the Netherlands Health Council (HCN), dating from 1978 and updated in 1993, might offer a way out in many cases.

From visual performance to visual ergonomics: a personal historic view.

During the authors active time in vision research a change in attitude took place from ‘visual performance’ as a criterion to justify higher light levels, to ‘visual ergonomics’ as a more comprehensive approach to improve visual work conditions. Some personal memories of this transition period may serve as a historic framework.