A person is considered blind if his central visual acuity, corrected with glasses, is not more than 20/200 in the better eye, as expressed in the Snellen notation.

A field defect in which the peripheral field has contracted to such an extent that the widest diameter of visual field subtends to an angular distance of no greater than 20 degrees, is also considered to be sufficiently disabling to constitute blindness.

Permanent and total disability shall mean a permanent physical or mental impairment which is disabling, and which, because of other factors such as age, training, experience, and social setting, substantially precludes a person from engaging in useful occupations, as a homemaker or as a wage earner in employment which exists in the community, and for which occupations the person has competence.