Welcome to question of the day #51

Eyetools question of the day #51

For people with age-related macular degeneration, proper illumination will allow reading of print 25% smaller than with poor illumination. As good light increases vision and contrast sensitivity it allows for a lower power magnifier to be used which in turn allows for increased reading distance and a wider field of view.

The traditional position for a localised lamp used for reading or some other near vision task is behind the person so that light comes over the shoulder onto the task. This can be very effective for standard reading distances but is difficult to combine with the use of a magnifier and/or very short working distance. Under these circumstances, it is likely that the person’s body will cast a shadow on the task and the light may create reflections from the magnifier surface. A better arrangement in this circumstance is to place the light in front of the person’s face with the shade arranged so that there is no light shining directly into the eyes.

Compact fluorescent bulbs are available where the long discharge tube is folded or bent into a circular or D-shaped configuration. High efficacy means that there is little energy loss as heat so that the lamp housing does not get hot. This means that people using these bulbs for near vision tasks can place their heads very close to the lamp without discomfort, and grasp the housing to adjust it without the risk of burning their hand. Lights which contain LEDs are efficient in terms of light production, electricity usage and longevity.