A cataract is the clouding of the natural lens in the eye. The lens itself comprises mostly water and protein and the protein normally allows the lens to remain clear and let light pass through. However the structure of the protein can change, resulting in clouding of the lens and blurred vision. The vast majority of cataracts are associated with ageing although rarely babies can be born with them or develop them in childhood. In other patients they are caused by such things as a blunt injury to the eye, inflammation in the eye (uveitis) or diabetes. Eye surgeons remove the natural lens and replace it with an artificial ‘intraocular’ lens to restore the lens’s transparency.
Over the last 60 years, cataract surgery has evolved from a sight saving operation to an operation focused on restoring quality vision. Multifocal lenses with diffractive optics and lenses that provide improved depth of focus have been developed to restore near vision.
Since those pioneering beginnings of cataract surgery, ophthalmologists at St Thomas’ have been at the forefront of these developments. Mr David Spalton, consultant ophthalmologist at St Thomas’ Hospital has been involved in research involving artificial lenses for over 20 years. He explained:
“When cataract surgery was first developed it was very much a sight saving operation, and of course still is in many parts of the world. But as technology has progressed, more advanced lenses have been developed that enable us to restore quality vision.
“We have extensive research programmes in place at St Thomas’ that enable us to objectively assess the lens in the eye. We assess near and distant vision, contrast sensitivity, movement of the intraocular lens and sophisticated changes in the optics by a technique called wavefront analysis which was originally developed by astronomers to look at light from distant galaxies.”
One of the aims of David Spalton and his team has been to develop an artificial lens which prevents residual lens cells growing back after a patient’s cataract has been removed. When residual cells grow back, the same symptoms that the patient had before the cataract operation redevelop, and often a laser procedure is required to restore vision. This research at St Thomas’ has had a considerable impact on cataract surgery as the percentage of patients who now require laser treatment for residual cellular growth after two years surgery has decreased from 50 to 10%, improving vision and saving many million pounds to the health care budget.
Another interest of the research team is to develop an intraocular lens that is fully functional in the eye, moving flexibly within it so that the patient is able to see clearly, both in the distance and close up without glasses. This is called restoring accommodation to the eye.
Later this year, David Spalton presents the prestigious Ridley Medal Lecture at the meeting of the European Society of Cataract and Refractive Surgeons (ESCRS) in Sept 2010. This is the largest ophthalmic society in Europe attracting about 5000 surgeons to its annual meeting and this biennial lecture is its highest award recognising the research that has been carried out at St Thomas' on cataract surgery and intraocular lens design over the last 20 years.
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Note to editors:
1. Contact: Andrea Ttofa, Guy's and St Thomas' NHS Foundation Trust tel: 020 7188 5577 or email: press@gstt.nhs.uk. Out of hours, please call our pager bureau on 0844 822 2888, ask for pager number 847704 and give the pager operator your message.
2. Guy's and St Thomas' provides around 850,000 patient contacts in acute and specialist hospital services every year. As one of the biggest NHS Trusts in the UK, it employs around 10,000 staff. The Trust works in partnership with the Schools of Medicine, Dentistry, Nursing and Biomedical Sciences of King's College London and other Higher Education Institutes to deliver high quality education and research. Website: www.guysandstthomas.nhs.uk
3. Guy’s and St Thomas’ is part of King’s Health Partners Academic Health Sciences Centre (AHSC), a pioneering collaboration between King’s College London, and Guy’s and St Thomas’, King’s College Hospital and South London and Maudsley NHS Foundation Trusts.
King’s Health Partners is one of only five AHSCs in the UK and brings together an unrivalled range and depth of clinical and research expertise, spanning both physical and mental health. Our combined strengths will drive improvements in care for patients, allowing them to benefit from breakthroughs in medical science and receive leading edge treatment at the earliest possible opportunity.
For more information, visit www.kingshealthpartners.org