You're allowed to claim a deduction for donating eyeglass (or any other items) only if you give them to a qualified organization. These include public charities, nonprofit schools and hospitals, government groups and religious organizations (see Resources to check the IRS' list). If you give your eyeglasses directly to a person, even if the recipient is in great need, you can't claim any tax benefits for your generosity.
When you donate eyeglasses to a qualified organization, you can deduct the fair market value on your taxes. The IRS defines the fair market value as the price a willing buyer would pay a willing seller, but does not publish a list of the values for various items. Used items tend to be worth substantially less than the price when new. Sometimes, tax preparers or charitable organizations will provide a list of commonly donated items with a price range for each that can inform your pricing.
Getting a Receipt
When you donate glasses, you don't need a receipt if your donation is worth less than $250 and it's impractical to get one, such as if you leave the eyeglasses at an unattended drop box. If you don't get a receipt, you need to keep a record for yourself of what you gave, when you gave it and which organization received it in case you are audited.
Calculating Tax Savings
The value of your donated eyeglasses reduces your taxable income for the year, but only if you itemize your deductions. If you don't itemize, you won't save anything on your taxes. It's financially worthwhile to itemize only if the total of your deductions is more than the standard deduction you are entitled to. If you do itemize, you can calculate your tax savings by multiplying your marginal tax rate -- the rate you pay on your last dollar of income -- by the amount you deduct for the value of your eyeglasses. For example, say you claim a $5 deduction for your eyeglasses. If you fall in the 25 percent tax bracket, that saves you $1.25 on your taxes.