THE TORSO AND NECK-Continued

Consider injury to cranial nerves, minimum rating if interfering to any extent with mastication 5326 Muscle hernia, extensive, without other injury to the muscle

5327 Muscle, new growth of, malignant (excluding soft-tissue sarcoma)

NOTE: The 100 percent rating will be continued for 6 months following the cessation of surgical, X-ray, antineoplastic chemotherapy or other therapeutic procedure. At this point, if there has been no local recurrence or metastases, the rating will be made on residuals.

5328 Muscle, new growth, benign, postoperative:

Rate on basis of impairment of function, i.e., limitation of motion, or scars, diagnostic code 7805, etc.

5329 Soft-tissue sarcoma (of muscle, fat, or fibrous connective tissue)

NOTE: The 100 percent rating will be continued for 6 months following the cessation of surgical, X-ray, antineoplastic chemotherapy or other therapeutic procedure. At this point, if there has been no local recurrence or metastases, the rating will be made on residuals.

Rat

ing

10

10

100

100

[29 FR 6718, May 22, 1964, as amended at 41 FR 11296, Mar. 18, 1976; 43 FR 45352, Oct. 2, 1978; 56 FR 51653, Oct. 15, 1991]

THE ORGANS OF SPECIAL SENSE

$4.75 Examination of visual acuity.

Ratings on account of visual impairments considered for service connection are, when practicable, to be based only on examination by specialists. Such special examinations should include uncorrected and corrected central visual acuity for distance and near, with record of the refraction. Snellen's test type or its equivalent will be used. Mydriatics should be routine, except when contraindicated. Funduscopic and ophthalmological findings must be recorded. The best distant vision obtainable after best correction by glasses will be the basis of rating, except in cases of keratoconus in which contact lenses are medically required. Also, if there exists a difference of more than 4 diopters of spherical correction between the two eyes, the best possible visual acuity of the poorer eye without glasses, or with a lens of not more than 4 diopters difference from that used with the better eye will be taken as the visual acuity of the poorer eye. When such a difference exists, close attention

will be given to the likelihood of congenital origin in mere refractive error. [40 FR 42537, Sept. 15, 1975]

§4.76 Examination of field vision.

Measurement of the visual field will be made when there is disease of the optic nerve or when otherwise indicated. The usual perimetric methods will be employed, using a standard perimeter and 3 mm. white test object. At least 16 meridians 221⁄2 degrees apart will be charted for each eye. (See Figure 1. For the 8 principal meridians, see table III.) The charts will be made a part of the report of examination. Not less than 2 recordings, and when possible, 3 will be made. The minimum limit for this function is established as a concentric central contraction of the visual field to 5o. This type of contraction of the visual field reduces the visual efficiency to zero. Where available the examination for form field should be supplemented, when indicated, by the use of tangent screen or campimeter. This last test is especially valuable in detection of scotoma.

[43 FR 45352, Oct. 2, 1978]

$4.76a Computation of average concentric contraction of visual fields. The extent of contraction of visual field in each eye is determined by recording the extent of the remaining visual fields in each of the eight 45 degree principal meridians. The number of degrees lost is determined at each meridian by subtracting the remaining degrees from the normal visual fields given in table III. The degrees lost are then added together to determine total degrees lost. This is subtracted from 500. The difference represents the total remaining degrees of visual field. The difference divided by eight represents the average contraction for rating purposes.

TABLE III-NORMAL VISUAL FIELD EXTENT AT 8 PRINCIPAL MERIDIANS

Figure 1. Chart of visual field showing normal field right eye and abnormal contraction visual field left eye.

tory and findings reflect disease or injury of the extrinsic muscles of the eye, or of the motor nerves supplying these muscles. The measurement will be performed using a Goldmann Perimeter Chart as in Figure 2 below. The chart identifies four major quadrants, (upward, downward, and two lateral) plus a central field (20 or less). The examiner will chart the areas in which diplopia exists, and such plotted chart will be made a part of the examination report. Muscle function is considered normal (20/40) when diplopia does not exist within 40° in the lateral or downward quadrants, or within 30° in the upward quadrant. Impairment of muscle function is to be supported in each instance by record of actual appropriate pathology. Diplopia which is only occasional or correctable is not considered a disability.