Vision has many components – and if any of these components are reduced, they can affect learning for a child. Visual acuity is the ability to see the letters on the eye chart, and is only one part of vision. It can affect learning if reduced because the child may not be able to see the board or see his or her paper. This is generally corrected with glasses or contact lenses.

There are many vital visual skills necessary for learning. Some of these vital visual skills are: eye movement control (the ability to move both eyes together to follow along a path, like a line of text);

simultaneous alignment at near, also known as convergence (lining up both eyes at the same point up close); sustaining alignment at near (holding both eyes lined up at the same point up close); gross visual-motor (moving through space without bumping into things by using information from your vision); fine visual-motor (writing, sewing, texting, and doing other small and close-up activities with accuracy by using information from your vision); and visual perception (the brain’s ability to make sense of what the eyes see).

Eye movement control is the coordinated movement of the eyes to follow along a line of text or follow a ball. When children have trouble with eye movement control, they may have trouble tracking while reading and they may lose their place, skip words or lines, and have trouble copying from the board.

Convergence is the coordinated movement and focus of our two eyes inward on close objects, such as books. Convergence insufficiency is a common problem with the development of these skills. When convergence is insufficient, it means that the eyes do not come together closely enough when looking at a near object like a book, so the eyes are essentially looking “past” the target or page of the book. It can also mean that convergence cannot be sustained properly. When we are not able to converge our eyes easily and accurately, problems may develop, such as: eye strain, headaches, double vision, difficulty reading and concentrating, avoidance of near work, poor sports performance, and dizziness or motion sickness.

Eye teaming and eye coordination problems like convergence insufficiency generally cannot be improved with eyeglasses or surgery. Vision therapy – an individualized program designed by a developmental optometrist that can help to correct vision dysfunctions – may be needed to improve eye coordination abilities, reduce symptoms, and alleviate discomfort when doing close work.

Our eyes have an automatic focusing system which adjusts the lens in order to see clearly at all distances. When we look far away, up close, and back again, our eyes change focus rapidly to allow us to see things clearly at all distances. A problem with how easily or quickly our eyes focus is called an accommodative dysfunction.

Normally, children have a large amount of focusing capacity. However, some do not have the ability to maintain focus for a long time while reading, or they may be unable to quickly change focus from near to distance to near, etc. Accommodative dysfunctions can cause: blurred vision; difficulty maintaining clear vision, especially at near; difficulty shifting focus from one distance to another; visual discomfort and eye strain; pain in or around the eye; fatigue; moving print; headaches; and avoidance of near work. In some cases, glasses for near use only, or in special bifocal form, may be needed. Improved focusing ability can usually be developed with vision therapy.

Adults can also have accommodative dysfunction. However, this is not to be confused with a very common visual condition called presbyopia, the term for age-related focusing problems. In adults, these are due to loss of the natural elasticity of the lens inside the eyes. As we age, the focusing lenses become less flexible, and we begin to experience blurred vision at close distances.

Visual perception is made up of many skills as well: sensory processing (accurate registration, interpretation, and response to sensory stimulation in the environment and the child’s own body); visual attention (focusing on important visual information and filtering out unimportant background information); visual discrimination (determining differences or similarities in objects based on size, color, shape, etc.); visual memory (recalling visual traits of a form or object); visual spatial relationships (understanding the relationships of objects within the environment); visual sequential-memory (recalling a sequence of objects in the correct order): visual figure ground (locating something in a busy background); visual form constancy (knowing that a form or shape is the same, even if it has been made smaller/larger or has been turned around); and visual closure (recognizing a form or object when part of the picture is missing).

If a child has difficulties with visual perception, he or she might have difficulty completing puzzles or dot to dots; planning actions in relation to objects around them; with spatial concepts such as “in, out, on, under, next to, up, down, in front of;” differentiating between “b, d, p, q;” re-

versing numbers or letters when writing; losing place on a page when reading or writing; remembering left and right; forgetting where to start reading; sequencing letters or numbers in words or math problems; remembering the alphabet in sequence; copying from one place to another (e.g. from board, from book, from one side of the paper to the other); remembering sight words; attending to a word on a printed page due to his/her inability to block out other words around it; and with hidden picture activities or finding a specific item in a cluttered desk.

If your child has many of these symptoms, you should have him or her seen by an optometrist who specializes in vision therapy.