A computer and smartphone is all you need if you want to take a test for glasses or contact lenses as a growing number of companies are offering online vision screenings.

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One fact needs to be made clear -- it's an eye screening and not an eye exam, Dr. David Anderson of Miamisburg Vision Care said.

That means the procedure will not include a check for real problems with your eyes such as blood pressure issues or diseases of the eye.

The American Optometric Association warned that online eye screenings often give inaccurate or misleading information.

“The AOA’s primary concern is that patient health and safety is at risk due to lack of understanding as to what services an online vision test company actually offers and can deliver to consumers,” former AOA president, Steven Loomis, said.

However, the American Academy of Opthalmology says the screenings may be appropriate for those who are 18 to 39 years old who have no major symptoms or corrective issues.

Larry Young, who wears glasses, said he prefers an in-office exam. But, if the technology improves, he said, "anything is possible. they have autonomous cars - but I wouldn't trust those either."

A spokesperson for Opternative, an online eye test provider, said the company's success rate is 99.6 percent. The company also recommends people undergo a full, in-office eye exam every two years.

Other companies that offer online eye tests include 1-800-Contacts, EyeQue, Lensabl.

The tests typically ask a series of questions about your eye health and use a smartphone, iPad or laptop to assess your vision.