Since you are paying for your dental and vision coverage with pre-tax dollars, you cannot claim the costs as deductible medical expenses.
"Pre-tax" means your employer paid the premiums with money you earned, but didn't have to pay income tax on - those earnings were not included in Box 1 (Wages) of your W-2.
Allowing you to deduct the costs from your taxable income, when the money used was never included in your taxable income would be a "double - benefit", not allowed by the IRS.
