Visual acuity is familiar, easy to quote, and often misunderstood. A patient with 20/20 central acuity may still have substantial visual difficulty from peripheral field loss, glare, reduced contrast sensitivity, double vision, poor depth perception, or impaired adaptation to light and dark. Conversely, reduced acuity in one eye does not automatically translate into the same functional limitation as equal loss in both eyes.
The National Eye Institute describes low vision in several patterns, including central loss, peripheral loss, night blindness, and blurred or hazy vision. These distinctions matter in litigation because the functional consequences differ. Central loss may interfere with reading and facial recognition. Peripheral loss may impair mobility and hazard detection. Diplopia can make driving, walking, and near work difficult even when each eye tests reasonably well by itself.
Objective measurement comes first
A careful damages evaluation considers best-corrected distance and near acuity, visual fields, ocular alignment and motility, contrast, color vision when relevant, and the structural condition responsible for the loss. Testing must also be internally consistent. Reliability indices on automated visual fields, variability between visits, refraction, ocular media, fatigue, and patient understanding can all influence the result.
Binocular function deserves particular attention. The visual system combines information from both eyes, so monocular and binocular measurements are not interchangeable. Loss of one eye can affect stereopsis and peripheral awareness, yet many individuals adapt well over time. The degree of disability therefore cannot be inferred from diagnosis alone.
Impairment is not the same as disability
Impairment ratings provide a standardized estimate of loss of bodily function. Disability is broader and asks how that impairment affects the person's ability to perform particular activities or work. The AMA Guides provide a structured framework for permanent impairment, but the edition and method required may vary by jurisdiction. The AMA specifically advises evaluators to confirm applicable state requirements.
Timing also matters. A permanent rating should generally reflect a stable condition after reasonable treatment and recovery. Future cataract surgery, corneal rehabilitation, retinal repair, low-vision services, or adaptation may materially change function. A premature rating risks treating a moving target as a final result.
Reported limitations should be compared with the measured deficit and the demands of the person's actual activities. Reading fine print, operating machinery, night driving, navigating stairs, and performing close binocular work rely on different aspects of vision. This does not mean that every complaint must map neatly onto one test. But it does mean that a persuasive damages opinion must explain how the ocular findings would likely affect the particular tasks at issue.
Authoritative references
Disclaimer: This article is provided solely for general educational purposes. It does not constitute legal or medical advice, establish an attorney-client, physician-patient, or expert-client relationship, or provide an expert opinion concerning any particular matter. The discussion is general, may not reflect later changes in the law or medicine, and should not be relied upon in making litigation, legal, or clinical decisions. Attorneys should independently verify the governing law and consult qualified counsel in the applicable jurisdiction. Medical conclusions require review of the complete facts and records of the individual case.