Convergence Excess is a binocular vision disorder characterized by the eyes over-focusing at near to the point of crossing in an attempt to keep images single while reading. The result of this overworked system is visual stress at near. There are two main physiological ways of dealing with this stress:
1) Becoming nearsighted, meaning making near vision more comfortable at the expense of distance clarity
2) Relaxing by suppressing, turning off the visual input to one eye, resulting in an eye turn at near
There are two main ways of alleviating that stress optometrically:
1) Prescribing a bifocal to relax the visual system at near
2) Optometric Vision Therapy to utilize the plasticity of the brain (ability of the brain to change) to regain proper control over the visual system.