Chicago-based Opternative has launched an online refractive eye exam service that helps consumers get prescriptions for glasses or contacts.

According to the company, the offering is registered with the FDA as a Class I device.

Consumers access Opternative's service on the web via desktop. Opternative asks users a few questions, like when their most recent eye exam was, and then takes the user through the eye exam, which lasts at most 25 minutes. Users take the test on a desktop computer but record results on a mobile device. After the exam, users can pay $40 to receive a prescription for glasses or contacts, which will arrive within 24 hours. Users can also pay $60 for both a glasses and contacts prescription. The service can also diagnose patients with nearsightedness, farsightedness, astigmatism, and emmetropia.

After users complete the online exam, a licensed ophthalmologist evaluates the patient’s results, health information, and medical history, including past vision exam records. Prescriptions are issued and signed by an ophthalmologist licensed in the patient’s state. Opternative currently operates in 27 states.

“Our technology and team of ophthalmologists make eye exams convenient and affordable while providing consumers a choice of where and when they want to receive eye exam services,” Opternative CEO Aaron Dallek said in a statement.

The company's eye exam is currently only available for adults between 18 and 40 and Opternative will not allow patients to use its prescription services more than four consecutive times within a five-year period without first receiving an eye health exam. Additionally, patients with certain symptoms or medical conditions will not be allowed to take the Opternative exam.

Opternative has completed a physician-led clinical trial of 1,500 patients recently, which found strong correlation between Opternative’s eye exam software and traditional in-office refractive eye exams.

The company has raised $3 million to date from Tribeca Venture Partners, Chicago Ventures, Healthbox, Pritzker Group, and Jump Capital, according to TechCrunch.

This isn't the company with a mobile eye exam services to make news this year, though it is one of the first that does not require peripheral equipment for the test.

In June, New York City-based Smart Vision Labs, which has developed a smartphone-based autorefractor for vision testing, raised $6.1 million. The device uses wavefront aberrometry to measure refractive errors, which determines the patient’s prescription.

Earlier this year, eye diagnostic tool maker EyeNetra launched a service called Blink, which sends a staffer to user’s home for vision tests, in New York City. Blink emphasizes that the appointments are only for users who need to be tested for glasses, not for eye health exams. The test costs $75 for one person, $130 for two people, or $170 for three people.

A month later, Warby Parker, an online eyeglass retailer, announced that they were investing in technology that allows consumers to conduct smartphone-based eye exams. The news came shortly after Warby Parker raised $100 million in a round led by T. Rowe Price — the company is now valued at $1.2 billion.