When people have restrictions, physically or mentally, they may to entitled to apply for a tax credit through the federal and provincial government. There are different ways for which a person can be eligible for the disability tax credit (DTC). In all cases, the impairment must be prolonged. Also, the person must meet one of the following criteria: Is markedly restricted in at least one of the basic activities of daily living. Is significantly restricted in two or more or the basic activities of daily living (can include a vision impairment). Needs life-sustaining therapy.