J Korean Ophthalmol Soc.  2002 Feb;43(2):332-336.

Effects of Retinal Illuminance on Visual Acuity and Fusion

• Kim NS
• Lee JH
• Chang YH
• Lee JB

Abstract

PURPOSE: We examined the effects of induced retinal illuminance on visual acuity and fusion.
METHODS
Fifty adults with best corrected visual acuity of 20/20 or better and normal binocularity and fusion were examined. To examine the effect of retinal illuminance on visual acuity and the effect of binocular difference of retinal illuminance on fusion, we used neutral density filter from 0.1 ND to 4.0 ND. While neutral density filter values were increased, we measured the least size fusion slide by major amblyoscope as well as the best corrected visual acuity.
RESULTS
The best corrected visual acuity and the level of fusion were decreased significantly when monocular retinal illuminance was reduced to 2.0 ND (P<0.01, P<0.01, respectively). Although the visual acuity and fusion were equally influenced by retinal illuminance, the effect on fusion was more prominent when retinal illuminance decreased greatly.
CONCLUSIONS
These results will be of help for the prevention and early detection of amblyopia, although further study will be needed in order to fully evaluate the influences of other factors on binocular fusion.

Keyword

Retinal illuminance; Visual acuity; Fusion; Neutral density filter

MeSH Terms

Adult
Amblyopia
Humans
Retinaldehyde*
Telescopes
Visual Acuity*
Retinaldehyde