AMA Guides® Newsletter - Issue Archive

Articles

1. Rating the Impact of Visual Impairment

   August Colenbrander

   Pages 1–6

   DOI: 10.1001/amaguidesnewsletters.2011.NovDec01

   Abstract

   The AMA Guides to the Evaluation of Permanent Impairment (AMA Guides) used the Snell Visual Efficiency Scale (1925). Following scientific progress, the Vision chapter in the fifth and sixth editions of the AMA Guides began using the Functional Vision Score (FVS) that is endorsed by the International Council of Ophthalmology and the International Society for Low Vision Research and Rehabilitation. Use of the FVS provided an opportunity to correct many inconsistencies in the VES system and also is better integrated with modern measurement methods and the ratings used for other organ systems. The FVS score is obtained by combining the Functional Acuity Score and the Functional Field Score; if any adjustments are introduced in this combination, they must be completely justified and cannot be based on subjective arguments. The disability is rated on the basis of functional considerations and is not influenced by nonfunctional factors. Combining visual acuity loss and visual field loss into a single number is attractive for administrative and legal purposes, but this step is meaningless in the context of rehabilitation because rehabilitation for visual acuity loss is entirely different from rehabilitation for visual field loss. The FVS system provides internationally endorsed statistical estimates of the effects of visual impairment on the ability to perform activities of daily living.
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2. Rating Visual System Impairment using the Sixth Edition: Technical Aspects

   Bernard R. Blais

   Pages 7–11

   DOI: 10.1001/amaguidesnewsletters.2011.NovDec02

   Abstract

   Use of The Visual System section of the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides), Sixth Edition, requires knowledge and skills in ophthalmology and assessing impairment. Visual acuity usually is measured using symbols (letters, numbers, pictures, or other symbols) presented in a letter chart format. The Visual Acuity Scale (VAS) is a linear scale with fixed increments and provides a reasonable estimate of acuity-related visual abilities; the associated impairment rating is a reasonable estimate of acuity-related performance loss. This article shows how to perform visual acuity calculations and how to assess impairment of visual fields, including visual field test procedures and calculations. Additional factors can lead to a loss of functional vision and can limit the individual's ability to perform activities of daily living and include contrast sensitivity, glare sensitivity, color vision defects, and binocularity, stereopsis, suppression, and diplopia. If functional vision is affected and is not accounted for by visual acuity or visual field loss, the impairment rating of the visual system can be adjusted but should be limited to an increase of the impairment rating of the visual system by, at most, 15 points (ie, less severe than the total loss of one eye). The ability to rate visual impairment requires significant knowledge and education, and therefore a physician trained in ophthalmology should perform the visual examination and visual system impairment rating.
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