The future of contact lenses

 
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Contact Lens Future

Past

The history of contact lenses provides ample reasons to be optimistic about their future. From hard glass contacts with their host of problems to disposable silicon-gel extended wears with their far fewer problems has been, largely, one long and successful journey. Problems, however, still remain. And so long there are problems, further development is always possible.

Present

Modern lenses made from high oxygen permeable material have improved lens quality many times over. They have excellent vision clarity, considerably reduced eye problems and are much more comfortable to wear. Today disposable extended wears represent the latest in contact lens technology. However, 26% of hydrogel extended contact wearers and 18% of RGP wearers still have eye complications.

Future

Further lens development must go beyond the disposable extended wear technology. Many believe that the main focus should be on developing material with still higher oxygen permeability since oxygen deprivation of the cornea is the root cause of many disorders. Furthermore, the material should be biocompatible and the lenses should have improved designs to deliver good vision clarity with fewer or almost no problems.

At the same time the consumer demands further increase in the period of extended wear. Such one sided developments conflict with the safety demands of the eye practitioners. Obviously a judicious balance will have to be struck

Future trends in contact lenses

Improved performance of contact lenses rests on their quality attribute. These are:

  • Vision clarity
  • Comfort
  • Absence of infections
  • Absence of deposits

Higher are these quality attributes better will be the performance of the lens.

These attributes and thereby lens performance can be improved by:

  • Improved materials
  • Improved surface treatment
  • Improved design

These are big technological challenges but not insurmountable ones. Hopefully they will be overcome sometime in the not too distant future.

Improved material

There are presently two main unresolved areas of concern. The first one is about people with myopia, presbyopia and astigmatism who make up more than half the lens wearing population. To correct these disorders thicker lenses are needed. Thicker lenses are problematic as they allow less oxygen to flow through them compared to thin lenses. The other problem is the closed eye lid which during sleep becomes an additional barrier to the flow of oxygen to the cornea.

Many see the solution to these problems in using lenses with still higher oxygen permeability, minimal water loss and deposit resistance. Another solution could be daily wear extended lenses which are replaced regularly.

Silicon-hydrogel lenses with relatively higher oxygen permeability than hydrogel has a remarkable property. Higher water content in silicon-hydrogel improves its oxygen permeability unlike in hydrogel where higher water content reduces the oxygen permeability.

The discomfort felt with RGP lenses may be reduced by using a more flexible material with an optimum design. Lenses made with such a silicon-hydrogel variety have been shown to conform more easily to the corneal shape.

Studies have shown that silicon hydrogen lens accumulate less protein and other deposits. Deposits should cease to be a problem if additionally lenses are regularly replaced and cleaned. Studies have also shown a significant reduction in the common ‘Dry eye’ problem in those wearing silicon hydrogel lenses.

Overall silicon hydrogel lenses have shown better performance and provide more comfort. All evidence points to silicon hydrogel as the material of the future.

Improved surface treatment

The high oxygen permeability of silicon-hydrogel also creates some problems. The surface treatment in silicon hydrogel lens makes it wettable and reduces the affinity for some protein deposits. But it increases the affinity for some kind of denatured deposits. Although the incidence is only 5% the problem must be resolved in the future.

Eye blinking is beneficial as it increases the tear amount which cleans the eye surface. But lenses reduce the tear volume. It is as yet a moot point whether surface treatment could improve the tear volume.

Improved design
Improved lens design with high oxygen permeable materials is expected to correct a broader range of refractive disorders. Improved lens designs should produce RGP lenses more comfortable in the initial period and lenses which reshape the astigmatic cornea better. Better designed lens should also lead to less aberration and better vision.

Lens care

Finally, no matter how advanced the lenses become, lens care with its strict cleaning and disinfecting regimen will always be needed. Used as they are, in contact with the eyes, it is difficult to imagine a future scenario where cleaning will not be needed.