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LOSS OF VISION Clearly distinguish between complete and partial loss of vision and rate complete loss of vision in both eyes as 85%, while complete loss of vision in one eye when the vision in the opposite eye is normal is rated at 24%. For partial loss of vision, rules to be followed in determining impairment include:
1. All medically acceptable attempts to correct must have been exhausted.
2. Determination must await 6 months freedom from all external signs of inflammation.
3. Determination to be deferred 12 months in case of
a. Extrinsic muscle disturbance
b. Retinal injury
c. Sympathetic ophthalmia
d. Traumatic cataract
4. Testing is to be performed with corrective lenses unless otherwise stipulated.
PRIMARY COORDINATE FACTORS The primary functions are:
1. Central Visual Acuity (CVA)
2. Visual Field Efficiency (VFE)
3. Ocular Motility (OM)
Maximum Limits for each Coordinate Factor MPPI states the standards for testing and the normal limits for each factor. The standards prescribed are identical to those established in the AMA document.Central visual acuity refers to the ability to recognize letters that subtend an angle of five minutes, each part of which subtends an angle of one minute at the distance viewed. The normal, or 100%, VA is considered to be 20/20 Snellen or AMA chart or 14/14/AMA card for near vision. These standards refer to a chart imprinted with block letters or numbers in gradually decreasing sites, identified by distances at which they are normally visible. It is used in testing visual acuity. The numerator is the test distance in feet. The denominator is the distance at which the smallest letter discriminated by the patient would subtend five minutes of arc.
Visual Field Efficiency The maximum, or normal, visual field is defined as 500 degrees,which is the sum of degrees in the eight principal meridians from the central point of fixation to the outermost limits of visual perception, using a 3 mm white target at 33 centimeters. 100%, or normal, VFE is visual extension from central point of fixation in the following eight principal meridians.
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