HIV Infection in the Dominican Republic

Abstract

fatigue that might be associated with VDT use. The main factor appears to be lack of blinking. While scrolling on a VDT, the user has a tendency to stare and decrease blinking to avoid missing anything on the screen. As with contact lens wearers, it is necessary to remind VDT users to blink sufficiently often to lubricate the cornea. This simple act will decrease ocular fatigue significantly.Ergonomics come into play with the location of VDT screens and the type of glasses prescribed, especially with users who wear bifocal glasses. Bifocals have a limited range of clear vision that is related to the age of the patient and the strength of the bifocal correction.Clear vision is often limited to an area at chest height or below at a distance of 30 to 45 cm (12 to 18 in). Unfortunately, the VDT is usually at a greater distance and often at face level or higher-out of the range of bifocal glasses unless the user moves unnaturally close to the screen and holds his head up at an unnatural angle. This will often cause neck discomfort.This problem may be essentially elim¬ inated with the prescription of progres¬ sive lenses, which enable all distances to be in focus and allow the visualization of the VDT screen with natural head and neck positions. Trifocals may function better than bifocal lenses, but are not as versatile as progressive lenses. Alter¬ natively, attempts should be made to position the VDT in a way that mini¬ mizes neck discomfort when viewing the screen.