There is a very simple answer to this and that is: it depends what the problem is. Multiple studies have shown that 25% of children have some form of vision or eye problem. These can be actual vision prescriptions like myopia or hyperopia . In these instances vision will be blurred and they are best corrected with a suitable pair of spectacles to sharpen vision for maximum learning efficiency in seeing the board, reading, computer etc. The most overlooked conditions both from a patient awareness perspective and by many practitioners are what are known as accommodative-vergence disorders. This is technical speak for problems with eye aiming and eye focussing and the ability to sustain these for longer periods when reading and learning. Accommodative dysfunction is a problem with the focusing system of the eye, particularly at near. You may be able to see clearly in general but have difficulty maintaining accurate, comfortable focus particularly with near work. Convergence insufficiency is a condition in which you have difficulty keeping both eyes turned in to point in the same position when doing close work e.g. reading, writing, computer work. Convergence excess describes a condition where the eyes do not exactly aim together; rather, they aim too close or in front of the object. As a consequence, blur, confusion or fatigue may result. Convergence excess will effect near work tasks, especially reading and writing.

Symptoms of all of these problems can include eyestrain, headaches, blurred vision, double vision, sleepiness and trouble remembering what was read. Rapid changes in convergence demands, such as copying from the blackboard, are often very difficult for children with convergence excess or insufficiency. Poor convergence is commonly associated with an accommodative insufficiency. The eyes are aimed closer in than desired in an attempt to compensate for reduced focus stamina or focus ability. This leads to a mismatch between vergence and focus, thus affecting binocular vision accuracy.

Individuals who have never refined the ability to maintain their eyes converged generally have very few visual symptoms. Children with this problem do tend, however, to have poorer fine eye-hand and visual motor skills and will tend to avoid near tasks as they have difficulty performing them. Those children who have acquired the convergence insufficiency problem tend to have more symptoms, particularly when doing prolonged near tasks. These symptoms may include, but are not necessarily limited to the following:

Difficulty sustaining attention at visually demanding tasks.
Visual fatigue or stress symptoms such as red eyes, sore eyes, frontal or temporal headaches, transient near and/or distance blur.
Occasionally a child will also complain of double vision or the letters moving or running (swirling).
Abnormal postural adaptations when trying to centre on near tasks, including head tilting or holding their work very close.
General fatigue and pain around the eyes.

Treatment of accommodation-convergence problems will require the use of therapeutic prescription of glasses to enhance the focus efficiency. In some cases, because these lenses reduce the visual demands on the visual system this is all that is needed to be done. In other cases, however, visual therapy will also be needed to rebuild and develop the visual stamina and convergence skills. It is important that the glasses are worn in the classroom as well as for all homework, reading, computer, or any prolonged close work tasks.