New vision in polymers

Researchers at Germany’s Fraunhofer Institute for Applied Polymer Research are developing new high-performance polymer materials to create ultra-thin, flexible eye implants for cataract sufferers.



The German team said lenses made from the materials could be folded during cataract replacement surgery and inserted through smaller incisions, making the procedure far less invasive.


Cataracts, caused by the slow crystallising of proteins, are one of the most common eye problems, generally appearing after the age of 50. Symptoms include clouded vision or higher sensitivity to glare. Conventionally, surgeons destroy a clouded lens with an ultrasound instrument, vacuum it out and replace it with a plastic lens.


The current incision needed for the procedure is 3mm, but researchers hope to reduce this to 1.5mm, removing the need for post-operative stitching, because the smaller wound would naturally heal itself. This could transform cataract replacement into an outpatient procedure.



However, there are no intraocular (within the eyeball) lenses available for implant at this scale of surgery, hence the need for the new polymers.



The key measure of a lens’s performance is its refractive index — a scale of how strongly light is refracted at the interface of two materials. Existing intraocular lenses have a refractive index of 1.5, but the Fraunhofer team said it had produced a lens with a far higher value than has previously been achieved, by using highly refractive acrylate materials with molecular structures known as cross-linkers, and polymers containing nanoparticles of titanium oxide. The key advantage of this material is its high optical transparency and flexibility, which means that it can be folded or rolled up.



Development of the polymers forms part of a wider project called micro-incision research in ophthalmology (MIRO), which is looking at new techniques for treating debilitating eye conditions.