|Keratoconus Contact Lens Fitting||
Scleral lenses have been around for hundreds of years, this is a lens designed to cover the whole of the visible part of your eye and more. They are still used in some cases where nothing else is possible or for some cosmetic instances such as special effects in the movies.
The latest innovation is mini-sclerals which have made somewhat of a revolution in contact lens fitting of ectatic corneas. The difference being that the lens is still quite a large RGP lens but significantly smaller than a full blown scleral lens. Scleral lenses can be anything up to 23mm in diameter whereas a mini or semi-scleral lens is usually between 13.5 and 16mm in diameter.
The effect s generally the same, however, they are designed to weight bear on the sclera (the white part of the eye) and not on the cornea itself. This results in better comfort, less mechanical trauma to the cornea and, hopefully, better vision.
The prescriptions are often simpler due to the fact that the cornea is completely vaulted and a almost perfect opposite corneal shape is created by the tears pooling between the cornea and the back surface of the lens creating an equal and opposite keractoconic surface ultimately restoring a uniform optical lens and elimination most if not all of the astigmatism. This can result in less ghosting and much crisper vision.
Their are some disadvantages however, the biggest of which is the insertion and removal. Due to their size and need to be filled with fluid prior to insertion they can be more difficult to handle. This is all surmountable and is only a matter of getting used to the intricacies of a new lens.
New Mini-Scleral Design
This new innovative design of mini-sclearal lens is borne out of several years research. It utilises a new approach to lens edge design. The lens edge tapers away from the eyeball offering a much more aligned fitting increasing comfort. They are designed to have large tear lens cavity thus neutralising all surface corneal irregularity.