Australian scientists are developing a therapeutic contact lens that acts as a bandage for eye surface injuries, and could fast track the healing of previously difficult to treat corneal wounds.The ‘bandage’ consists of cells with special wound-healing properties, said researchers from the Queensland University of Technology (QUT) in Australia.”These cells, known as limbal mesenchymal stromal cells (L-MSC), would be isolated from donor eye tissue and subsequently attached to the inner surface of a special type of contact lens known as a scleral lens,” said Professor Damien Harkin from QUT, who is based at the Queensland Eye Institute.”The donor cells are readily accessible from tissue that is usually discarded after routine corneal transplants,” Harkin said.”Based upon preliminary data we believe that the donor cells release a range of wound-healing factors that encourage repair of the eye’s surface,” he said.Harkin said the lenses could be available within hours of patients presenting to an eye clinic with either recently acquired or chronic damage to their eye’s surface.”Our therapy could provide welcome relief for patients suffering from chronic conditions such as corneal ulcers and persistent surface defects that have not responded to conventional therapies,” he said.”The new treatment could also become useful as a part of the first-line therapy in the management of acute eye injuries experienced in the work place or at home arising from exposure to caustic chemicals, scalding liquids or excessive heat,” Harkin said.Harkin said the current treatment typically involved using bandages prepared from amniotic membrane donated from human placentas.The type of lens that is best for you will depend upon several factors. These include how often you want to wear your lenses – for example do you want to wear them just for certain activities such as sport, or do you want to wear them most of the time, instead of glasses?As soft lenses are initially more comfortable than RGP lenses, they are ideal for people who only want to wear lenses occasionally. RGP lenses are a little more uncomfortable than soft lenses at first, so they take a bit more getting used to. But, they last longer and may be better for people who have irregularly shaped eyes or have astigmatism (see over page). Special types of RGP lenses that you wear only at night, are available to temporarily correct short-sight. This treatment orthokeratology.Some people find that if they wear contact lenses their eyes may feel dry. This may be worse with some types of lenses than others. If you notice this, you may find that changing to a different type of contact lens or reducing the amount of time you wear your lenses will help you. Make sure you mention this when you go for your contact lens check-up so that your optometrist can suggest what to do about it.”Amniotic membrane (AM) provides a limited supply of growth factors and components with anti-inflammatory and wound-healing properties,” he said.Harkin said the new treatment could be available to patients within as little as a few years subject to completion of rigorous clinical trials. Unlike soft lenses, RGP lenses do not mould to the shape of your eyes. This means that they can correct some astigmatism without needing to be specially designed. This is because your tears fill in the gap between the lens and your eye, neutralising the astigmatism and allowing you to see clearly. This means that it doesn’t matter if the lens rotates. If you have a lot of astigmatism, spherical RGP lenses may not fit you and you may need to have toric RGP lenses. These lenses will be specially designed for you and so are unlikely to rotate on your eye. This means that they will give more stable vision than soft toric lenses.
