A Lenscrafter television advertisement showing a man being fitted for glasses caught my attention with its unidiomatic use of the verb fit.
At the beginning of the ad, the man is in a traditional examining room, looking anxiously through multiple lenses. At the end of the ad, he is seated comfortably in front of a device that ascertains his prescription by digital means. A voice-over asks, “Why have your glasses fit manually?” My internal usage detector immediately corrected the question to “Why have your glasses fitted manually?”
American speakers do sometimes use fit instead of fitted as a past form, as in this example: “In his case, the punishment fit the crime.”
In the context of having glasses made to measure, however, fitted is the preferred past form in standard US English.
The following examples from US sources indicate that Lenscrafter’s use of fit as a past form does not agree with common usage in the context of fitting eyeglasses:
Safety glasses which are professionally measured and fitted to the individual are recommended for permanent employees whose job duties require frequent eye protection.—University of North Carolina
You can also send us new frames you’ve already bought and had fitted and we will fit new lenses into them.—Texas-based mail-order business.
After this testing has been completed, your eye doctor will gather additional information so you can be fitted with contact lenses.—US vision information site.
This is why it is important to have your eyeglasses fitted before you bring them home.—New Hampshire optometry office.
Fitted is also the preferred form in the context of installing or equipping something:
Since I last wrote about this issue in 2002, more rental cars have been fitted with such systems, which can instantly relay information on your car’s speed, route and position to the rental company.—LA Times
More than 200 paroled burglars in Connecticut will be fitted with global tracking devices as part of the state’s response to a home invasion in Cheshire last month that claimed the lives of a woman and her two daughters.—NY Times
After selecting the plan, Hernandez learned it didn’t cover the audiologist who had fitted her daughter, who is partially deaf, with a hearing aid.—Chicago Tribune
An artist is planning to release about 2000 pigeons fitted with LED lights over New York’s East River.—UPI news site.
Finally, here are some examples of things being “fitted manually”:
Most polar exploration aircraft must be fitted manually with skis for operating on snow.—Popular Mechanics
To change the tower lights’ colors, plastic gels are fitted manually over metal halide lamps or floodlights and fluorescent tubes in various color combinations.—Article about the Empire State Building on a US trivia site
The models generated for helix αA, helix αB and helix αC located in TraF/VirB10NT were fitted manually in one monomer of the difference map.
—US government science site.
Both forms, fit and fitted, are used as adjectives, but with different meanings. Compare:
This dress is fit for a princess. (“suitable”)
He never buys fitted sheets. (“designed to fit closely”)