Accommodative Excess refers to the tendency to focus closer in than the page being read, ie the individual will focus as if the book is closer than it really is.
This is commonly found in cases of Convergence Insufficiency, where the individual has difficulty aiming the eyes at near at the same place on the page, by overfocusing the eyes are able to be brought together to the one point.
Accommodative Excess however reduces visual stamina and can affect binocular vision.
In school aged children this is of concern as it both reduces visual efficiency but also delays ability to shift focus between distance and near tasks.
It is common in these cases for symptoms of headaches and/or sore eyes to be reported.
In cases of Accommodative Excess, there is often the report of transient blur in the distance when looking up after doing near tasks such as reading.
The risk factor is myopia (shortsightedness) being induced later in life, often in the teenage years, should accommodative excess be allowed to continue.
Treatment is the use of a Therapuetic spectacle lens prescription, this usually prescribed as a multifocal lens. The concept being to utilise the bottom section of the lens to improve near binocular vision levels whilst still allowing clear distance vision through the top of the lens, this being especially important at school and university.
Also in some cases Vision Therapy may be indicated to retrain the visual system to operate in a more efficient manner.