To evaluate vision health, the functional exam will test for:
Eye Teaming/Convergence/ Depth Perception / Binocular Vision
This is when the eyes align to focus on the same point and work as a team in a coordinated fashion. If eye teaming is poor, it can cause double vision, poor 3D depth perception, eyestrain, and fatigue, especially during reading and close work.
Furthermore, poor eye teaming skills (which occurs among 5-10% of children) can result in difficulties with convergence and issues with depth perception.
Convergence insufficiency occurs when the eyes turn out while reading and doing close work. One needs to exercise immense effort to keep the eyes from drifting out, which, in turn, causes double vision and headaches.
Convergence excess is when the eyes tend to turn inwards during reading and close work. The symptoms resemble those in convergence insufficiency.
Visual Acuity- Nearsightedness
Can the patient see clearly at close distances? This is essential for reading, writing and doing other close work.
Focusing / Accommodation
Can the patient maintain clear vision at varying distances? Quick eye focus adjustment is crucial to learning, reading, writing, and sports.
For example: When a child moves his or her gaze from the board to his book, the eye muscles must contract or tighten, which causes the eye lens shape to change, allows the child to see clearly. To look back at the board, the child needs to relax the focusing muscle for clear distance vision.
Eye Tracking and Eye Movement
In those with healthy vision, eyes move accurately, smoothly, and quickly from place to place. These movements rapidly and accurately scan the visual environment for information. For example, if a child switches its gaze from the board to their book and back, the eyes need to accurately jump from one target to the next. This is also the case in reading when jumping from one word to another, or for following moving objects in sports. In fact, eye-hand coordination in any activity begins with accurate eye movements.
For example: tracking allows you to understand the distance between you and a car, and the speed at which it’s driving. It also allows you to judge the distance and, if you’re going to honk, how loud the honk should be.
Poor eye movement and eye-tracking abilities can result in poor reading skills, speed, comprehension, and concentration.
Does your child confuse or reverse letters or words (b, d; p, q; saw, was) past a certain age? After the age of seven, such reversals may indicate a visual perceptual dysfunction. The sooner you address letter reversals, the less ingrained the habit will be.
Accurate perception of color is crucial as many activities and occupations are based on this visual skill. Color is often used to emphasize a point or provide instructions. In daily living, color perception is needed to match outfits, obey traffic lights and work in certain professions, such as graphic design. Red-green color deficiency is the most common form of color-blindness and the condition primarily affects males.