Implantable contact lenses

Thousands of glasses and contact lens wearers could benefit from the development of an implantable semi-permanent lens.

The device, developed by researchers at CSIRO, part of the Co-operative Research Centre for Eye Research and Technology in Sydney, is made from a synthetic perfluoropolyether polymer, and is suitable for both long and short-sighted people.The highly porous synthetic lens, which aims to produce a long-term yet reversible solution to sight problems, is implanted just under the surface of the cornea at the front of the eye.

The transparent material encourages the growth of the eye’s tissue across its surface, incorporating it into the corneal tissue through the normal wound-healing process. It has an antibacterial coating to prevent infection and the development of ulcers.

Its developers, who are hoping to start human trials of the product, say the lens could be implanted for up to five years, or until the patient’s refractive needs alter. When a change of prescription is required, the lens could be removed and replaced with one of a different strength.

The researchers expect that the implantable contact lens will be able to correct refractive error from -6 dioptres of short-sightedness through to +6 of long-sightedness.

‘The requirements for such a material are stringent, including non-toxicity, transparency, permeability and surface characteristics that permit the migration and persistent adhesion of corneal epithelial tissue,’ said Associate Professor Deborah Sweeney from CSIRO.

‘Almost two-thirds of the world’s population require some form of vision correction and this research goes some way to providing an affordable, permanent solution to refractive eye disorders.’

The lens could also be used as a replacement for scarred or diseased corneal tissue, eliminating the problems of limited supply, tissue rejection and viral infection associated with corneal transplants.

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