trial lenses

tri·al lens·es

a series of cylindric and spheric lenses used in testing vision.

tri·al lenses

(trī'ăl lenz'ĕz)
A series of cylindric and spheric lenses used in testing vision.
References in periodicals archive ?
Tenders are invited for Instruments and equipment medical, surgical and dental (air sterilizer, pnevmotonometr projector signs schilova lamp, a set of trial lenses with trial frames, colposcope, tsystouretroskop observation, diatermokoahulyator surgical, medical suction electric, Centrifuges etc.
A case from 1894 containing 43 pairs of metal-rimmed and goldrimmed trial lenses, plus two trial frames.
The vision exam for dogs involves eye drops, trial lenses and streak retinoscopy.
When you're being fitted for contacts, make sure your eye health professional provides you with a pair of trial lenses before ordering the final pair.
After the lieutenant put the trial lenses in his eyes, I checked his vision and the fit.
He said: "There is not much data about the issue but the re-use of trial lenses did not seem to us a good idea.
By the afternoon, I had sorted through the trial lenses and had begun labelling the donated glasses.
It then follows that many of the younger new fits will be more complex prescriptions; this will often mean that trial lenses need to be ordered.
A trial frame and a set of trial lenses doesn't guarantee a successful refraction, in the same way throwing some high-end frames on your shelf won't guarantee success selling them.
This can be confirmed by checking the amount of prism thinning surfaced at the prism reference point by taking equivalent amounts of prism from the trial set, correctly positioning the spectacle frame on the patient and simultaneously placing the trial lenses base up before each spectacle lens.