What is an intraocular lens?
An intraocular lens is a human-made miniature medical device which is implanted into your eye to replace the eye’s natural lens removed during cataract surgery. For short they are known as IOLs. These often have been described as a tiny artificial lens for the eye. Your natural lens normally bends or refracts light rays that enter the eye, to focus them on the redness so that you can see. You have to have a clear lens to see, but if you had a cataract and the vision has become cloudy, and things have looked blurry, hazy or less colourful with the cataract then you have to have cataract surgery to remove this cloudy lens and replace it with the clear IOL.
Are there different types of IOL?
There are different types of IOLs. They are commonly made of silicone or acrylic and then coated with a special UV filter material to help protect your retina from the sun’s harmful ultraviolet light rays. IOLs come in different focusing powers, just in the same way that glasses and contact lenses come in various focusing strengths and each eye has a specific focusing power requirement. Therefore when you come to your assessment with Mr Jaheed Khan or Miss Laura Crawley once the diagnosis of cataract has been made and you want to have cataract surgery, your ophthalmologist will ask the nurse to measure the length of the eye and curve of the cornea to determine what your IOL focusing power has to be. They will discuss with you whether you want to have clear vision for near or for distance.
Where did intraocular lenses come from?
Intraocular lenses have been used for a long time. We credit the ophthalmologist Mr Harold Ridley (who was later known as Sir Nicholas Harold Lloyd Ridley), born in 1906 and died 2001, with inventing the first intraocular lens. He first performed an intraocular lens implant on 29th November 1949 at St Thomas’ Hospital in London. St Thomas’ Hospital still has an excellent ophthalmology department, following on his tradition. However, there are many competent ophthalmologists in London, and we have two of the best cataract surgeons here at Clinica London, Mr Jaheed Khan or Miss Laura Crawley. Although the original material used was Perspex CQ which was Polymethylmethacrylate (PMMA) manufactured by the Rayner Company and made by ICI, the materials available now are very much more sophisticated. Medical device companies invested millions of pounds in research to adapt the design, shape and flexibility to get the best design for your eye. Going back to Ridley, why did he choose the acrylic plastic material PMMA? During World War II, he noted that an RAF (Royal Air Force) pilot retained pieces of a shattered canopy of his plane in their eye which was known as Plexiglass and was, in fact, an acrylic resin. He further noted that the material was so inert that he thought he could make an intraocular lens using this material. However, despite his innovating discovery, it took some years into the 1970s when further developments in lens surgery and safer techniques were available. Now, cataract surgery is one of the most frequently performed eye operations in the world. I will tell you more about the intraocular lens in my next blog post about what the materials are and the different types available for you. I will tell you about the mono lens and the prime lens. Read on tomorrow.