If you itemize your deductions on Form 1040, Schedule A, the threshold for unreimbursed medical and dental expenses you paid for yourself, your spouse, and your dependents must exceed 10 percent of your adjusted gross income before a deduction is permitted.
Most people who itemize their deductions can claim deductions for unreimbursed medical expenses, those which are not covered by health insurance, that exceed 10 percent of their adjusted gross income.
Temporary exemption for taxpayers age 65 and older
There is a temporary exemption for individuals age 65 and older until Dec. 31, 2016. If you are 65 years or older, you may continue to deduct total medical expenses that exceed 7.5 percent of your adjusted gross income through tax year 2016. If you are married and only one of you is age 65 or older, you may still deduct total medical expenses that exceed 7.5 percent of your adjusted gross income.
This exemption is temporary. Beginning Jan. 1, 2017, the 10 percent threshold will apply to all taxpayers, including those over 65.
The IRS has an excellent Q & A posted on their website