Working Diagnosis:
Cortical Visual Impairment

Treatment:
No definitive treatment or intervention to change course of diagnosis.

Outcome:
Patient should be cleared to participate in Track and Field with protective eyewear - street wear with polycarbonate lenses or fashion eyewear.

Author's Comments:
Cortical Visual Impairment (CVI) refers to the visual impairment that stems from a lesion in the occipital lobe. The brain is unable to effectively process and manage the visual stimulation that is obtained by the eye. Occipital brain lesions are usually secondary to congenital defects, traumatic injuries, strokes or metabolic disorders. Diagnosis is obtain by ruling out refractory or anatomical causes of visual impairment, thus vision cannot be fixed by refraction - contacts or glasses. The athlete's vision used in competition known as "sports vision"refers to the visual abilities of depth perception, dynamic visual acuity, eye movement, peripheral vision and momentary vision. An athlete with poor spots vision can lead to poor performances and possible injuries. When depth perception is inadequate, it leads to difficulty in accurately determining velocity and spatial distances of an incoming objects and may lead to mistakes in perception and puts them at risk for an injury. Thus, it is vitally important for physicians to screen athletes for visual impairments before sport participation which should be done during the annual sports physical. During the exam, the athlete is evaluated for visual acuity using a Snellen eye test. A failed test is a result of a single eye greater than 20/40. The athlete would need to follow up with an eye specialist for further evaluation before clearance. Most common cause of failed vision screens are refractory deficiencies, which leads to athletes being prescribed contacts or glasses and clearance to play with protective eyewear. Although, most visual problems can be corrected with eyeglasses and contacts, a study by Beckerman and Hitzman (YEAR) showed that many young athletes do not use corrected vision while playing and other studies show that those with refractive errors may not see a significant difference in depth perception when corrected by eyeglasses. AD did not find benefit in correcting his vision with eyeglasses or contacts, which leads us to presume his likely etiology may be CVI based on his long standing history as a child with impaired R eye vision which is not able to correct with corrective glasses/contacts. He most likely would benefit from an MRI, which would give a definitive diagnosis. It is still recommended that athletes with visual problems wear protective eyewear. It is essential to consider eye-protection for athletes whose vision is already impaired in 1 eye. An athlete is deemed functionally 1-eyed if the loss of the better eye results in significant change in lifestyle. Athletes who are functionally 1-eyed and participate in sports who carry a high risk of eye injury may be individually evaluated and allowed to participate if they are with an appropriate eye wear. Baseball is considered a high-risk category of sports-related eye injury risk to the unprotected player. Cross country as well as Track and field is considered low risk. Pending definitive diagnosis for AD, he would still need to be medically cleared for sports participation. He likely will need clearance from an eye-specialist with recommendation allow sports participation with protective eyewear, even if it provides correction or not. Should he choose to continue playing baseball, he would need an ASTM standard F803 protective eyewear. If he was to continue track and field, an "eye-safe" sport, the minimal requirement is street-wear with polycarbonate lenses or even fashion eyewear.

Editor's Comments:
Cortical visual impairment (CVI) is a decrease in visual response due to a problem in the brain, particularly in the areas controlling vision. It is caused by brain damage from prematurity, stroke, decreased blood supply, decreased oxygenation, brain malformation or infection, hydrocephalus (increased pressure in the brain), seizure, metabolic disease, infection, head trauma and other neurologic disorders that can cause damage to the visual parts of the brain. Getting a thorough history is vital including birth and developmental history. On exam, a child with CVI typically will have a normal eye exam or has an eye condition that cannot account for the abnormal visual behavior. In developed countries, it is one of the most frequent causes of visual impairment in children. The term "cortical blindness" has been used before to mean CVI but it is an older term and itself can be misleading. CVI children usually have some level of vision that may show some improvement over time. These children usually exhibit characteristic behaviors such as having distinct color preference, delayed visual response (latency), abnormalities of visual field
preference for looking at lights, better visual response for near objects than distant objects, and difficulty with complex visual objects, groupings or environments. Vision improvement does occur with CVI as brain matures, there are new connections that can develop in the brain to overcome the initial injury or deficit. It is difficult, however, to initially predict future visual function. Based on the characteristics seen in CVI children, interventions can help maximize performance. Once a pediatric ophthalmologist diagnoses visual impairment from CVI, it will provide medical necessity for vision services. Treatment in the form of visual stimulation exercises such as but not limited to using visual materials presented in a simple uncluttered manner with increasing complexity, presentation of visual material from different directions/angles, use of variable level of light in environment, extra time for responses to visual stimuli, avoidance of over stimulation or doing visual tasks when child is hungry, tired, frustrated are key forms of intervention. It is important to keep in mind that children with CVI may have other associated visual disorders such as structural eye disease, misaligned eyes, or a significant refractive error so a thorough H&P, complete assessment and eventual referral to a pediatric ophthalmologist is of vital importance.

References:
Beckerman and Hitzeman, Optometry, 2001

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