Yes, you can deduct prescription eyeglasses as a medical expense. As long as the glasses are a treatment prescribed by a qualified medical professional, the expenses is deductible regardless of the cost.
See IRS Publication 502 for more information:
Eye Exam
You can include in medical expenses the amount you pay for eye examinations.
Eyeglasses
You can include in medical expenses amounts you pay for eyeglasses and contact lenses needed for medical reasons. See
Contact Lenses
, earlier, for more information.