Visual aids for the partially sighted.

THOSE who are substantially and permanently handicapped by defective vision resulting from illness, injury, or congenital deformity may be described as partially sighted. The following criteria are suggested as a general guide in estimating " substantial handicap": (1) Visual acuity 3/60 to 6/60, with full visual fields. (2) Visual acuity up to 6/24, with moderate contraction of the visual fields, opacities of the ocular media, or aphakia. (3) Visual acuity of 6/18 or better, if gross visual field defects (e.g. hemianopia, pigmentary degeneration, etc.) are present.