Quantifying and qualifying levels of visual impairment and disability is an important component in forensic ophthalmology. Visual impairment as causation or as contributory negligence may be an important factor when analyzing a personal injury action. Importantly, interpreting visual impairment according to accepted standards, and analysis that clearly defines the level of impairment based on loss of vision is critical for assessing damages.
Normal vision is correctable to 20/40 or better. In most states, an individual must have vision of at least 20/40 correctable with contact lenses or glasses in at least one eye to qualify for a driver’s license.
Visual acuity correctable by contact lenses or glasses to 20/200 or less in both eyes and visual fields of less than 10 degrees centrally constitutes legal blindness in the United States.
Eye Muscle Function
Impairment of the eye muscles may cause double vision, loss of depth perception, or loss of accommodation and the ability to see close-up. For example, paralysis of the third cranial nerve can produce lid droop, paralysis of accommodation, with dilation and immobility of the pupil. A finding of severe visual impairment based primarily on impaired eye muscle function needs to be supported by measurements that reflect deficiency of eye muscle function.
- Special Situations
Aphakia, the loss of the natural lens of the eye represents a visual handicap in the presence of loss of central visual acuity.
Cases in Point
Dr. Reynard was an expert retained by defendant Time Warner Cable to evaluate visual impairment and disability in an individual who collided with a street cable while riding a bicycle. Impairment of vision by significant cataracts was instrumental in a obtaining a jury defense verdict.
Dr. Reynard provided courtroom testimony for assisting administrative law judges in Social Security Administration evaluate visual impairment in patients with a variety of medical conditions that included diabetes, thyroid disease, and eye injury.