Who can certify people as eligible?

In cases of blindness, visual impairment, or physical handicap, eligibility may be certified by doctors of medicine; doctors of osteopathy; ophthalmologists; optometrists; registered nurses; therapists; and professional staff of hospitals, institutions, and public or private welfare agencies (e.g., social workers, caseworkers, counselors, rehabilitation teachers, and superintendents). In the absence of any of these, certification may be made by professional librarians or by any person whose competence under specific circumstances is acceptable to the Library of Congress.