Historically, hard contact lenses were frequently made of this material.

She wore her hard contact lenses.

You wear these hard contact lenses to bed, and when you wake up, you can go without glasses or contacts all day."

Soft contact lenses are also more fragile than hard contact lenses and can rip or tear easily.

The base of the statue is composed of passé objects like boxes for 35-millimeter slides and cases for hard contact lenses.

Contact lenses can be roughly classified under two main categories: soft contact lenses and hard contact lenses.

With most hard contact lenses, there will be a 2- to 4-week break-in period during which you wear the lenses for increasingly longer periods of time each day.

Furthermore, the reduction was more pronounced in patients wearing hard contact lenses than in patients wearing soft contact lenses.

Three options exist for the treatment of astigmatism: spectacles, contact lenses (either hard contact lenses or toric contact lenses), and refractive surgery.

One industry body recommends that patients wearing hard contact lenses should stop wearing them for a minimum of six weeks plus another six weeks for every three years the hard contacts have been worn.

The company was formed after the two brothers left a career in the contact lens industry which was founded by their father, Adolph Lombart, and built into the world's largest manufacturer of hard contact lenses.

But for the 10 percent to 20 percent of keratoconus patients who can no longer get a comfortable fit or good vision with hard contact lenses, he added, "The cost is well worth it, if a transplant can be avoided."

In certain instances, hard contact lenses were shown to cause the same changes in corneal structure as soft contact lenses, though these changes were more dramatic because rigid lenses are capable of inflicting greater trauma on the eyes.

PMMA is a transparent thermoplastic available for use as ocular prosthesis, replacement intraocular lenses when the original lens has been removed in the treatment of cataracts and has historically been used as hard contact lenses (see poly(methyl methacrylate)).

The hard contact lenses Ferrigno wore to simulate the Hulk's electric-green eyes had to be removed every 15 minutes because he found wearing them physically painful, and the green fright wig he wore as the Hulk was made of dyed yak hair.

Following cessation of hard contact lens usage, corneal sensitivity has been shown to be fully regained after several months: patients who had worn hard contact lenses for a decade or longer were able to regain normal corneal sensitivity after four months of not wearing contact lenses at all.