A person is eligible for aid to the blind who has central visual acuity of 20 /200
or less in the better eye with correcting lenses, or whose vision in the better eye
is restricted to a field which subtends an angle of not greater than 20 degrees.
A peripheral field loss in which the visual field efficiency is reduced to 30% or
less may be considered equally disabling, as may certain other ocular conditions which
do not necessarily involve field loss but which constitute a severe handicap.