The definitions to some commonly used terms in Behavioural Optometry, as well as words we may be using to discuss you or your child's vision problems:

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Accommodation (Acc)

• the process by which the eye changes optical power to maintain a clear image or focus on an object as its distance varies. Accommodation acts like the “zooming in” mechanism of the eye.

• The accommodation reflex is a reflex action of the eye, in response to focusing on a near object, then looking at distant object (and vice versa), comprising coordinated changes in binocular co-ordination, lens shape and pupil size.

 

Convergence

• the simultaneous inward movement of both eyes toward each other, usually in an effort to maintain single binocular vision when viewing an object. The “cross-eyed” appearance is one of excessive convergence..

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Convergence Insufficiency

• occurs when your eyes don't work together while you're trying to focus on a nearby object. When you read or look at a close object, your eyes need to turn inward together (converge) to focus. This gives you binocular vision, enabling you to see a single image.

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Divergence

• the simultaneous outward movement of both eyes away from each other, usually in an effort to maintain single binocular vision when viewing an object.

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Eye movement control (EMC)

• refers to the voluntary or involuntary movement of the eyes, helping in acquiring, fixating and tracking visual stimuli. This control is critical for efficient ball sports and reading.

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Spatial Awareness

• the thinking concept of left/right position of yourself and others in the environment. It is an organised knowledge of objects in relation to oneself in that given space.

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Visual Acuity

• the measurement used to specify ones range of clear vision at different distances.

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Accommodation/Convergence Dysfunction

• describes a breakdown or underdevelopment in the relationship of the eyes working together at focusing and alignment.