What is it?

Visual Inefficiency Syndrome (VIS) is a term we use to represent discomfort and dysfunction in near-vision tasks. VIS may be due to any combination of intraocular, oculomotor, neuromuscular and brain feedback dysfunctions and symptoms that individually and collectively interfere with information processing by the visual system.

Inefficient processing of visual information between the eye and the brain can lead to any of the subjective symptoms listed on the previous page. VIS can result in poor reading performance, lower than expected academic performance, poor sports performance and a variety of other problems in any tasks that require rapid or dynamic processing of input through the eyes.

During vision screening, Gemstone doctors rapidly determine whether a student might have VIS by measuring the visual behaviors listed below. The criterion for "normal" in each component is set according to published clinical and/or scientific standards, and varies with the age of the student.

In VIS, individuals are deficient in one or more of the following areas:

1. Focusing. The ability to focus each eye's internal lens close to the face. Called the "near point of accommodation."
   
   The ability to rapidly and accurately change the shape of the eye's lens, using the internal ciliary muscles. Called "accommodative facility."
   
   
2. Teaming. The ability to move both eyes together to attain single vision close to the face. Called the "near point of convergence."
   
   The ability to move the two eyes together in a coordinated manner in order to maintain the plane of vision the same for the two eyes. Measurements of "break" and "recovery" reveal the so-called "vergence ranges."
   
   
3. Tracking. The ability to move the eyes rapidly and accurately across a page without the use of a finger or other device.
   
   
4. Symptoms. The ability to read and to use the eyes routinely for near work with little or no discomfort.