The Senate Judiciary Committee’s antitrust panel is looking into how three major pharmaceutical manufacturers—Novartis’s Alcon division, Johnson & Johnson and Valeant’s Bausch + Lomb unit—decided to set minimum prices for prescription contacts. Reuters reports that the committee will determine if the minimum prices harm consumers.

The newswire notes that setting a minimum price has been legal since a 2007 Supreme Court ruling said such a move is OK, but antitrust experts tell Reuters that manufacturers may have set minimums as a way to prompt optometrists to write prescriptions for their brand.

Novartis tells Reuters it decided to go with a minimum retail price to keep patients from pumping doctors for product information only to purchase contacts online at lower prices.