Soft Contact Lenses

The use of soft plastic for the manufacture of contact lenses was first suggested by Professor Ottowichterle in Czechoslovakia in 1960. Together with D. Lim, a chemist, and M. Dreifus, an ophthalmologist, some lenses were produced and fitted and a report was given in the Czech literature.

Subsequent, Bausch and Lomb Optical Co. of the USA purchased the Czechoslovakian patent and started manufacturing these lenses in the United States. Several new laboratories around the world have come out with various types of hydrophillis soft lenses.

The principal advantage of the soft lens is its initial comfort, mainly attributable to the softness of the material. The other contributing factors are the larger diameter of the lens and its very thin edges, so that when the lens is fitted, it gives the right limited movement on the eye. This fitting technique produces minimum contact between the lens and lid margins, thus reducing lid and eye sensation. The recent Bausch and Lomb soft lenses have dramatically improved the fitting of lenses by mounding the corneal curvature of average size.

Soft contact lenses are a godsend for patients with over-sensitive eyes who, in spite of all efforts of skilled practitioners, are uncomfortable with hard lenses. Such patients take to soft lenses from the first moment as there is no tearing or redness of the eye, and hardly any sensation of grit.

The period for adapting to the soft lenses passes extremely quickly in comparison with hard lenses. Patients comfortably wear these lenses through their working hours without any significant feeling of tiredness.

There are hard-lens-users who have fully adapted to their lenses to the extent that they are sometimes unaware of even the presence of the lenses in their eyes. However, they still have a noticeable narrowing of the visible fissure of the eyes, created by an unconscious effort on their part.

A hard-lens-user (whose lens has a smaller seeing area, Le. optic zone) may have to make a ’squinting effort’ to help centre the lens geometrically to improve his/her vision. This effort may be conscious, but subconsciously the orbicular is muscles are continually tensed. This may also account for the complaint of some new hard-lens users that their eyes feel tired or they want to shut them near the end of their wearing schedule.

A comfort contributing factor with soft lens is its larger optic zone.

Fitting contact lenses is both an art and a science. And like the artist or the scientist, a contact lens practitioner cannot do his best work without all the tools of this trade at his disposal. In contact lens’ fitting this means, apart from being fully equipped with all the instrumentation, the practitioner must have access to all the various lens designs available, and be able to use them skillfully, judiciously and effectively as per the requirement of each individual patient in close coordination with the ophthalmologist.