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Functional Vision Assessments

The functional vision assessment includes a variety of evaluations that test the child's use of vision and visual efficiency in daily activities. The assessment, administered over several sessions, determines how the child accesses his/her visual environment, such as how far s/he can sit from the chalkboard or what print size s/he is able to see. A certified teacher of students with visual impairments completes the assessment; contributions from the child's Orientation and Mobility instructor are helpful as well. Parents, caregivers, and the child's teacher(s) are asked to give input about how the child performs in the community and the school setting. From this assessment, a report is generated that addresses multiple issues:

• Near and distance acuity: An acuity measurement is taken at near range (usually at a distance of 16 inches) using a near vision acuity chart. This measurement is often recorded in print size. For example, the teacher may record that the child can read 2M print (large print) at 16 inches. Other functional near tasks might also be used in the evaluation (e.g., how the child accesses information on baseball cards, identification of coins, etc.). Distance visual acuity is typically measured at a distance of 10 or 20 feet. A distance vision chart such as the Feinbloom or Snellen is often used. Other functional distance tasks may include the distance at which the child can see print on the whiteboard or imitate hand movements given by the physical education teacher.
• Peripheral visual field: Peripheral vision is the ability to see movement or objects outside of the immediate line of vision. Field loss is measured in degrees. For example, if a child has a 20 degree field loss, his/her visual field does not extend through a complete 180 degrees left to right.
• Reading level and speeds: An informal reading inventory indicates the grade level at which a child is reading as well as how fast s/he is reading in comparison to her/his peers.
• Current print functioning: The functional vision assessment should state the child's primary mode of reading, whether it is regular print, large print, optical devices, or Braille.
• Examples of both near and distance information: The assessment report should include examples of environmental features such as faces, signs, and travel cues the child can see and at what distance the child can see each feature.
• Light sensitivity: Light sensitivity has implications for how the student performs in a variety of illuminated settings. Children with diagnoses such as albinism or achromatopsia are significantly affected by higher levels of illumination and often perform tasks better under less illumination. There are also visual conditions for which additional lighting is necessary. For a majority of visual conditions, glare will adversely affect visual functioning.
• Colour perception: Colour perception is the ability to perceive differences in colour. Because many facets of daily life are influenced by colour (e.g., traffic lights, crayons, clothing), a child's ability to differentiate colours needs to be known.
• Convergence: Convergence is the necessary inward movement of the eyes in order to focus on a near object.
• Eye movements: Eye movements of children and youth refer to the ability to track a moving object in vertical, horizontal, oblique, and circular directions. Such eye movements are used when reading, copying work from the whiteboard, playing sports, and driving.
• Eye preference: Eye preference is a term used to describe the eye a person prefers to use for accessing his/her visual environment. Although not always, the preferred eye is often the eye with the better acuity.
• Muscle balance: Muscle balance is a term used to describe the alignment of the eyes and how they move together. Proper alignment is needed for the eyes to work together. In addition, proper muscle balance is essential for the ability to converge.
• Binocular vision: Binocular vision is a person's ability to perceive three-dimensional depth by fusing the images of each eye.
• Depth perception: Depth perception is the ability to distinguish an object's solidity and its position in space relative to other objects not in the same plane.
• Visual efficiency: Visual efficiency refers to how well a child completes tasks that require a visual skill.
• Educational implications: Educational implications are generally statements that address how a child's visual impairment will affect the child's functioning in a school setting.
• Recommendations: Recommendations are typically statements that reflect suggestions from the teacher for students with visual impairments about programming and how to make successful adaptations and accommodations.

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