A Chicago optometrist has created a digital eye exam that adults can take on their computers and smartphones, My Fox Chicago reported. The test, called Opternative, takes 25 minutes or less and produces a prescription from a registered ophthalmologist within 24 hours. The test costs users $40. According to OkCopay, an online service that tracks out-of-pocket medical expenses, the national median cost of an eye exam is $85. Opternative co-founder Dr. Steven Lee thought of the idea years ago after one of his patients asked whether an easier eye exam was available.