In our profession, there have been many tests introduced over the last decades, which we may perform to investigate and accurately determine problems and anomalies of, and then correction of/for specific seeing conditions.
Every patient is unique and vision requirements are becoming more specific for the varied environments one may be involved in. Just checking if a person can read a small line of letters on a chart and putting lenses up in front of each eye till the letters are clearest is not a comprehensive visual examination!
So we want to investigate the following in the tests we do:
1. How well does each eye see individually.
2. What lens is required to give optimum (best) vision clarity for R+L eyes? (Both at Distance and at Near)
3. Do the two eyes work (team) together, is one eye ‘lazy’ (in some cases both can be!)-and do they team together equally in all directions of gaze?
4. How do the eyes move in all directions of gaze-individually and together? (level of eye movement control)
5. How do the pupils of the eyes respond to different stimuli ( what happens to the pupil when light is shone into the eyes, pupils respond when we look at a far object and then back to a near object and with the eyes looking in close and then out into the distance)
6. Can the visual system comprehend differences in depth between objects?
7. Does the patient see colours correctly?
8. How does the system react when changes of focus are required-From far to near viewing and when forced to focus quickly and relax out again?
9. How do the eye muscles team together and how do they respond to changing pressure caused by looking closer and then further away and back again.
10. All the above tests also will be modified to determine how sustainable the skills are in each patient. i.e. – the effect of stress and fatigue on visual efficiency. “Can you do what you have to do well and for a long time!!!”
11. The effect of age on the findings at both far and near working positions.Age presents many challenges to vision-but handled correctly can help achieve good quality seeing.
From all of these different tests, the optimum lens is determined for each eye, and the appropriate correction/aid to vision will be given. This may take the form of, spectacles, contact lenses, vision therapy, reading specific therapy or a combination of the aforementioned.
A comprehensive visual examination is as you can ‘see’ not a one test fits all scenario.