MIAMI (CBSMiami) — On average, a person will pay about $200 for a pair of prescription glasses. Add on a designer name and fancy frames and the price goes way up.

But some glasses are selling online for as little as $7.

With the help of two women who ordered two pairs a piece, some of the bargain glasses were taken to an optometrist to see how they measured up.

Ann Petersen has been wearing glasses for 23 years. Monique Paananen has been wearing them for at least 15 years. They know how expensive a new pair can cost, that’s why it didn’t take too much convincing to get them to focus on a new way to find glasses.

“I’d be willing to give it a shot I guess. It’s a lot less cost than what I’m paying currently,” said Petersen.

Petersen ordered her glasses online from Zenni Optical. After a simple phone call to her eye doctor, she plugged in her prescription.

“I just bought a pair of classic frame glasses,” said Petersen.

She ordered her first pair for $6.95 and her second for $9.95.

Paananen went to EyeBuyDirect. She got a pair for $6.95 and paid $14.95 for her second.

“Sure doesn’t seem like a bad price,” Paananen said.

Two weeks later, when all four pairs came in, the women paid a visit to Perspectives Vision Clinic.

Dr. Marcie Nichols wanted to see what they got for their money and if the prescriptions they ordered matched with what she measured.

Nichols spotted the first issue with one of Petersen’s pairs – Petersen’s astigmatism correction was off.

“When your astigmatism correction isn’t made properly in a prescription it can be very hard to adapt to,” Dr. Nichols said.

The doctor said that could lead to eye strain or headaches but the biggest problem came later with pupillary distance. Measured in millimeters, PD is the distance between your pupils that ensures your lenses are placed in the right spot.

“If the prescription isn’t centered right over the pupil then it can definitely throw the way you focus through it off,” Dr. Nichols said.

The PD number usually isn’t included in your prescription from your doctor. Instead, the measurement is done on site.

So in the case of their orders, Peterson and Paananen took the measurement themselves following online directions.

“They are wrong in all of them,” Dr. Nichols said.

The measuring mistake became clear when Petersen and Paananen received their new glasses. A black dot was placed on the glasses where the pupil should be and it was off every time.

It’s recommended that you get your PD from your eye doctor and don’t do it yourself for the most accurate measurement.

As for what Petersen and Paananen thought of the feel and the fit, Paananen seemed to have more luck than Petersen.

“They actually fit pretty good. I’d wear them,” said Paananen.

“If I look straight ahead I’m looking over the top of the frames,” said Petersen.

Dr. Nichols considers it a profession of perfectionism.

“It’s so important to have the proper prescription with the proper lenses so you can be the most comfortable and efficient that you can be,” said Dr. Nichols.

She believes the consequences are too severe to blur the lines.

In the case of the test, it left two customers seeing things differently.

Nichols said if people do decide to order online, take them into a professional to have them adjusted, which in most cases is free.

It’s also good to know what size and shape frames look good on your face first before ordering. Many websites allow you to upload a photo of yourself first to see what certain glasses will look like.

Both of the websites they used to order from have return policies. EyeBuyDirect offers a replacement or a refund within 14 days of receiving the glasses but the customer has to cover the shipping cost. Zenni Optical takes returns for 30 days.

A spokesperson said all glasses are shipped within tolerance levels of the American National Institute of Standards.  All customer service representatives at Zenni have optical licenses.