By Suzanne Le Mignot

(CBS) — You get an eye exam and a prescription for contacts or glasses and you never leave your house. That’s the reality new technology offers lens-wearers, but the exam, has critics, reports CBS 2’s Suzanne Le Mignot.

Convenience and cost led Carlin Thomas to try a do-it-yourself eye exam to refill her contact lens prescription.

“I knew that I was definitely going to be saving money by not walking into any type of vision center,” Thomas said.

Thomas says it normally costs her about $150 to see the doctor for an eye exam. The at-home eye exam is $40. It’s $60 if you want prescriptions for both glasses and contacts.

She says it was “super easy and it took 20 minutes” and her prescription was emailed to her within 24 hours.

“I purchased contacts online and they were sent to me within two days,” Thomas said.

The test was created by Chicago-based Opternative. You need a smartphone and a computer.

Your smartphone asks the questions your doctor would. Your computer screen is your eye chart.

Dr. Steven Lee founded the company with CEO Aaron Dallek.

“Patients love the convenience,” Dallek said.

Convenience may come with a price. Dr. Eric Baas is a spokesperson for the American Optometric Association. He says the Opternative exam is not enough and that patients need to see a practitioner every year.

“This simply does not replace a comprehensive eye examination that can uncover, you know, sight threatening and even life threatening diseases,” said Dr. Baas said.

Dallek says they recommend their patients get an eye health exam every two years.

“I know that I would see a doctor anyways once every two years to test for glaucoma, astigmatism,” Thomas said. I take my eye health very seriously.”

Right now, Opternative has opthamologists who fill prescriptions for those between the ages of 18 and 40. The company is hoping to be able to fill prescriptions for patients between the ages of 40 and 65, by the year 2017.