Other companies like 1-800-Contacts also sell major contact brands to consumers, filling orders through copies of prescriptions or getting the prescription information and confirming its accuracy with the consumer’s eye care practitioner.

The Federal Trade Commission, which oversees the market, allows what is known as “passive verification.” Under this method, sellers can try to verify prescriptions through faxes and voice messages and, if eye doctors don’t respond within eight business hours, the orders can be filled. The rule was created in the early 2000s, when companies like 1-800-Contacts pushed to sell brand-name lenses and ran up against eye doctors who did not want to work with them.

Hubble — and its founders and co-chief executives, Ben Cogan and Jesse Horwitz — saw an opportunity in the rule.

A sudden jump in Mr. Cogan’s lens prices in 2015 led to the idea for Hubble — monthly shipments of daily lenses that cost roughly $1 a day. (Prices have since increased.) At the time, he was working for Harry’s, the subscription razor brand, while Mr. Horwitz was on the investment team for Columbia University’s endowment fund.

“It was one of three or four or five things I was tinkering around with,” Mr. Horwitz said at a conference in January, “and we said for all of them, anything that I can go actually raise a seed round for and sort of have investors be stupid alongside me, I’ll go do that one. And so that’s why we did Hubble.”

In December 2015, when Mr. Cogan was seeking a lens manufacturer, he contacted Dr. Sally Dillehay, who was then the chief medical officer at a small lens company and has worked in the contact lens industry for more than 30 years. During a telephone call, Mr. Cogan laid out a plan to move consumers from their prescribed brands and into a private label brand through passive verification, Dr. Dillehay said. This would put consumers into a new type of lens that the patient’s doctor had not prescribed, she said.

“I told them I did not want to be involved with such a company and described in great detail why contact lenses are not generic items like socks or razors, how even small micron level changes in something such as the edge design can completely alter the fit and safety profile of a contact lens,” said Dr. Dillehay, who now runs a consulting company called ClinTrialSolutions in Georgia.