Types of lenses

A rigid lens is characterized by:

• Its material: PMMA (polymethylmethcrylate) or family of fluo-siloxane-methacrylates whose silicone component gives a very good oxygen permeability and therefore less risk of hypoxia.
• Its geometry: Sphero-aspheric, Aspheric, Toric
• Its diameter: there are several diameters adapted to each case
• Its radius of curvature, the choice of which will depend on the shape of the cornea
• Its power: there is a wide choice of power

Having a wide choice of material and models allows your ophthalmologist a personalized adaptation.

Particularity of the rigid lens compared to the flexible

There exists under the rigid lens a meniscus of tear corresponding to a layer of the tear film posterior to the contact lens essential to the corneal metabolism, it is 10 times more important under the LR than under the LS. LR allows better oxygenation of the cornea.
Infections and allergies are much less common in rigid lenses than in soft lenses.

They are indicated for:

• Children because they provide better safety and physiological respect of the cornea
• Strong ametropia and rigid lenses give better visual quality than soft lenses
• Lacrimal dryness (air conditioning, at work on screen, smoky atmospheres, hot air)
• Progressive intolerance to soft lenses, patients “at the end of soft”
• Irregular Cornea (Keratoconus / Post Graft / Post Lasik / Post Traumatic)
• Continuous wearing up to 30 days possible: the rigid lenses respect the ocular physiology, they do not cause lack of oxygen (acute or chronic), which makes it possible to propose some rigid lenses in prolonged port (day and night) in certain special cases.

The limits of rigid lenses

• Occasional Wear
• The lack of motivation because more difficult to bear in the beginning compared to soft lenses.

• NO ! the colored lens is not a beauty accessory, it can not be bought in perfumery or other beauty space!
• NO ! Lenses are not lent between girlfriends for an evening, the risk of infection related to germs carried by the lens is very important, the AIDS virus has, for example, was found in small amounts in the tears of infected people .
• Yes ! the colored lens is a medical device subject to the same rules of prudence and hygiene rules as all other soft lenses.
• Yes! Colored lenses require the same care as all lenses: rigorous hygiene is essential.
• Yes ! it requires adaptation in his ophthalmologist as for other soft lenses.
• Colored lenses will be delivered by your optician and on medical prescription.
• Colored lenses can be flat (that is, without optical correction) for those who do not need it and want to wear lenses only for aesthetic reasons, but they also correct myopic, hyperopic and astigmatism.

Unlike other so-called contact lenses, scleral lenses are larger in diameter, do not rest on the cornea but on the sclera (the “white” of the eye), less sensitive and less fragile.

This avoids direct contact with the cornea, which is protected by a reservoir of liquid (physiological saline), This allows a constant hydration and oxygenation of the cornea, promoting healing and maintaining a constant level of hydration and therefore greater than any other tear substitute.

They are indicated in pathologies of the ocular surface for which the therapies usually proposed remain rare and often ineffective:

• Neurotrophic keratitis
• Stevens Johnson’s case,
• rosacea
• Severe eye dryness

They are indicated in corneal surface abnormalities that can not be corrected by glasses or other types of lenses:

• keratoconus,
• Cornea Plana,
• Very important irregular astigmatism
  • Post transplant,
  • Post refractive surgery or
  • Post traumatic.