Reasons for contact lens intolerance | Contact lens intolerance

Reasons for contact lens intolerance

Acute contact lens intolerance is caused by foreign bodies under the lens or by a surface injury. However, intolerance can also develop in the long term as a result of excessive wearing time and lack of oxygen on the surface. The contact lens material with its different properties is of great importance, especially in problematic eyes.

Also the even moistening of the lens and the different tendency to evaporation of tear fluid depending on the lens plays an important role in the compatibility. In addition, the influences of the composition of the care product (see contact lens care) or unsuitable environments with a lot of dust, chemical vapors and very dry air draft are the cause of contact lens intolerance. The main reason for not tolerating contact lenses, however, is the so-called “dry eye”, especially in connection with inflammation of the eyelid margin (blepharitis).

40-50% of contact lens wearers report dry eyes, which is significantly more than for non-contact lens wearers. It is crucial to treat dry eye and eyelid rim inflammation correctly. Consistent application of warm and moist compresses with “lid edge hygiene” can then restore more comfortable contact lens wearing for many patients with contact lens intolerance.

Types of contact lenses

  • Hard contact lenses barely touch the eye because they float on a film of tears, which means that the corneal surface can continue to be nourished quite well by the tears and the oxygen supply. Because of this and the more regular moistening/wetting and thus cleaning of the eye, there are fewer problems with air dryness and chemical vapors. However, they fall out of the eye more easily and are therefore less suitable for contact sports and in dusty environments.

    For very severe astigmatism or even keratoconus, hard contact lenses are the only applicable contact lens form.

  • Soft contact lenses on the other hand can hardly be lost (even when swimming). Even with a dusty environment there are fewer problems, but they are unsuitable. in dry air and with chemical vaporsA major disadvantage is a poorer supply of oxygen to the surface of the eye, as the contact lenses sit directly on the eye and “suck in”, so to speak. Regular, at least half-yearly check-ups by the ophthalmologist are absolutely necessary here in order to diagnose oxygen deficiency symptoms of the cornea in time and thus avoid permanent damage. Soft contact lenses should also be inserted one hour after getting up and removed one hour before going to bed, so that the cornea gets more oxygen before and after the night.