A blog post penned by one of the UK’s most renowned ophthalmic surgeons, Shafiq Rehman.
It may be allegorical, but it is often thought that the inventor of the intra-ocular lens, Sir Harold Ridley MBE, was first prompted to think about this idea after a throw-away remark by a medical student observing what passed for cataract surgery back in the early 1940’s. Whether this story is true or not, what is not in doubt is the tremendous impact this simple idea had on cataract surgery.
Let’s remember that prior to the advent of the first lens implant inserted into a human eye in 1949, cataract surgery consisted simply of removing the cloudy natural lens. Full stop. Period. With nothing to replace the focusing power of the natural human lens, most patients ended up having to wear very thick high-powered glasses to be able to see reasonably clearly.
Allow me to digress briefly –a quick foray into the optics of the eye.
Light entering the eye has to be focused onto the light sensitive Retina. The retina lines the inside of the eyeball and coverts light impulses into electrical signals which travel down the optic nerve to the brain. The brain converts these signals into what we actually see. If the light falling on the retina is not properly focused, what you see is out of focus and the eye has two major focusing elements.
First the cornea (the clear window at the front) and secondly the natural lens. The cornea provides roughly 2/3 of the focusing power of the average eye so the natural lens provides the remaining 1/3 of the focusing power. By removing the natural lens (because it’s gone cloudy as it does when we diagnose cataract) we are removing 1/3 of the focusing power of the eye. So, without a lens implant to replace that focusing power, the result would be an eye that is grossly under powered in terms of its focusing ability. This can be managed by wearing high positive (plus) power lenses to help the eye regain focus.
Now let’s fast forward about 70 years to the current era – Intraocular lens implants (IOL) are firmly established and accepted all over the world and are absolutely routinely implanted after removal of the cataract in the same procedure. But we have come though enormous advances in lens technology in materials, optical quality and characteristics, flexibility to allow insertion through incisions as small as sub 2.0mm and we also now have the ability to modulate the prescription of the patient’s eye as never before.
Whilst the very first lens implants were essentially solid clear plastic devices (PMMA – similar to Perspex) and came with only a single focusing power. Today’s patients can benefit from the many generations of cumulatively iterative evolution in IOL technology.
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We now have the capability to measure the eye to incredible levels of accuracy. These advanced measurements are fed into complex computer algorithms to allow the surgeon to very accurately target a certain level of prescription for the given eye. This remarkable increase in ‘predictive accuracy’ has really taken off over the last 15-20 years in particular, so much so that today cataract surgery is almost as effective as Laser vision correction when it comes to correcting eyesight prescriptions. If you have been short sighted, long sighted or astigmatic all your life – we believe cataract surgery today is truly a once in a lifetime opportunity for you to break free from the bonds of suffering from any optical prescriptions. Indeed, it is now possible with advanced technology Trifocal and extended focus type IOL’s to very reliably transition most cataract patients into a future life with little or no need for any corrective glasses at all and that can often include being able to see well for distance, read text and smartphones and use VDU / laptops with great freedom.
If there is one slight downside to the amazing technology and surgical advances that we have seen developing over the last several decades, it is that healthcare systems have not always kept pace with developments. In the UK, NHS and private medical provision for cataract surgery is largely limited to standard mono-focal lens implants. These implants can provide a degree of spectacle freedom after surgery in a small number of patients, however the majority will likely still require corrective glasses for far vision and almost certainly for close range and VDU range vision.
For some patients this is perfectly acceptable, but for those who would like to take full advantage of all the advances outlined above why not consider a complimentary consultation with one of our refractive cataract surgeons who can provide bespoke advice on what type of cataract surgery is best placed to meet your individual requirements?
Remember – Cataract surgery is a once in a lifetime opportunity to have the kind of vision that you always have wanted. To find out more about how we can help, book a free consultation.
By Author: Shafiq Rehman
Mr Rehman is a highly acclaimed ophthalmologist with 27 years of experience.