Disability deduction for totally blind and permanently physically disabled residents requires medical certification to claim tax relief. Section 80U allows a specified deduction in computing total income of a resident individual who at the end of the previous year is totally blind or suffers a permanent physical disability substantially reducing capacity for gainful employment; the individual must produce, for the first assessment year in which the deduction is claimed, a certificate from a registered medical practitioner (an oculist in cases of total blindness, or a registered medical practitioner for other permanent physical disabilities).