Glossary A
A
ACCOMMODATION
The capacity of the eye to see objects clearly at close distances, thanks to the reflex bending of the crystalline lens. A second reflex is associated with accommodation: convergence.
ACUITY CHART
A chart that shows lines of characters in various sizes, used to measure visual acuity.
ADDITION
The difference in correction between far vision and near vision.
AQUEOUS HUMOUR
A transparent liquid located between the cornea and the crystalline lens and responsible (along with the vitreous humour) for maintaining the eyeball’s shape and level of pressure. (see EYE)
ASTIGMATISM
An anomaly that in most cases is due to an irregularity in the curvature of the cornea, producing a distorted view of objects.