Gas permeable and hard contact lenses

Contact lenses

Contact lenses are an excellent choice for nearly anyone who needs vision correction and doesn't want to wear eyeglasses full time. Contact lenses carry no age restriction; adults and children can equally use them. New technologies and lens design provide quality vision at both distance and up close.

Diopta offers a wide range of contact lenses and contact lens solutions of top global manufacturers: Bausch +Lomb, Alcon, Optix, CooperVision, Opticus.

Daily, monthly, quarterly and annual replacement lenses are available as well as daily-wear and extended-wear contacts to meet vision needs and lifestyle of users.

Contact lenses offer many benefits over eyeglasses, apart from their aesthetic value:

  • better visual acuity (up to 30% compared to vision correction eyeglasses)

  • optimal vision correction, even in cases when eyes require a different prescription

  • wider field of view as there are no frames to obstruct vision

  • no fogging up, deep indents around the nose and pinching behind the ears

The right choice of contact lenses depends on many factors, including refractive errors, expectations and lifestyle of patients. There are several types of contact lenses, based on the type of lens material they are made of: soft lenses, gas permeable (GP) lenses and hard (PMMA) lenses.


PMMA lenses are conventional hard contact lenses made from a transparent rigid plastic material called polymethyl methacrylate (PMMA).

PMMA lenses have excellent optical properties, but they do not allow for oxygen transfer to the cornea. The only way for this vital element to reach the cornea is for tears to wash underneath the lens with each blink. In order for this blink-induced, tear-pumping action to occur, PMMA lenses have to be made relatively small in size.

PMMA lenses have been replaced by gas permeable lenses and are rarely prescribed today.

Gas permeable (GP) contact lenses are rigid lenses made of durable plastic that transmits oxygen. Most GP contact lenses incorporate silicone, which makes them more flexible than PMMA. Silicone is oxygen permeable, so oxygen can pass directly through GP contact lenses to keep the cornea healthy.

They are designed for patients with keratoconus and irregular astigmatism and can be used to correct any type of refractive error. GP contacts are the best choice for individuals for whom soft contacts don't produce the desired visual acuity.

It usually takes some time for eyes to adjust to gas permeable contact lenses when users first start wearing them.


  • stable and sharp vision

  • easy to handle and care for

  • last longer than soft contacts

  • good solution for corneal conditions that soft contacts and eyeglasses cannot correct

Optix (Leda Perm GP and hard (PMMA) contact lenses) and Optikus are available.

When using contact lenses it's important to follow rules for determining the optimum lens power and guidelines for proper lens wear and care.

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