NEW YORK—Vision-Ease Lens, a unit of Insight Equity A.P. X. LP, is suing Transitions Optical for allegedly monopolizing the market for photochromic spectacle lenses.

In a complaint filed July 27 in the United States District Court for the District of Delaware, Vision-Ease claims that Transitions Optical controls more than 85 percent of the photochromic lens market. The complaint alleges that Transitions violated U.S. antitrust laws and Florida’s Deceptive and Unfair Trade Practices Act by engaging in “anticompetitive acts to maintain monopoly power and unfairly restrain trade in the photochromic ophthalmic lens market.” Vision-Ease claims that Transitions’ actions have reduced competition, raised prices, and restricted output.

According to the court documents, “Transitions’ anticompetitive acts have harmed the public by causing higher prices and reducing offerings for photochromic ophthalmic lenses, stifling product research and development, and raising barriers of entry to prevent competition. Transitions’ acts have harmed Vision-Ease by hindering or preventing Vision-Ease from marketing and selling photochromic lenses in competition with Transitions’ photochromic lenses.”

Additionally, the Vision-Ease complaint claims that “Transitions has maintained its monopoly power by engaging in a variety of actions which…thwarted competition and foreclosed substantial portions of the retail and wholesale distribution channels.” Vision-Ease also alleges that Transitions refused to deal with competitors or customers who offered “competitive products, exclusionary contracts, and tying arrangements and bundled discounts.”