Getting the best results from cataract surgery

What determines your outcome after cataract surgery? Most people view cataract surgery as a simple procedure with a guaranteed outcome of clear distance vision without glasses. Cataract surgery is a complex micro-surgery that takes 7-10 years of surgical training to perform well and with a low risk of complications. Assuming that you are having surgery by a consultant ophthalmologist who is an experienced surgeon, how predictable is your post-operative result and vision.

On of the critical tests before cataract surgery is called biometry. Biometry measures various anatomical features of your eye including corneal curvature, eye ball length and natural lens position. This information is fed into a formula that predicts the outcome from a specific lens implanted into the eye. Unlike a pair of glasses where your optician can ask you whether your vision is clearer with one lens or another, your eye surgeon needs to predict the lens strength that will give a certain result. In other words for each patient the formula will predict that X powered lens results in virtually no prescription and clear distance vision.

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A typical biometry read out with lens predictions

If everything was that simple everyone would always have perfect results. However, modern lens prediction formulae are at best accurate to within +/-0.5 dioptres (the unit of a glasses prescription) in 70% of people and within +/- 1 dioptre in 90% of patients. 10% of patients can be outside these limits. Astigmatism may also affect clarity of post op vision. Some of these patients will require glasses for their best possible vision.

Whilst modern cataract surgery is highly successful and life enhancing, outcomes are determined by predictability of lens formulae. For the majority of people this is perfectly fine, but if you are paying to have a multifocal lens then you obviously want to have perfect vision. For the average cataract surgeon faced with a unpredicted outcome and hence a patient with blurred vision after multifocal lenses the option is to either perform a lens exchange operation or encourage the patient to simply wear glasses. The other less invasive and more precise option is the ability to perform laser eye surgery to refine the outcome of surgery to achieve perfect vision. This can eliminate residual prescription and astigmatism.

Choosing a surgeon that is able to perform laser eye surgery as well as cataract surgery is beneficial for the simple reason that lens prediction isn't exact and because this allows your surgeon to achieve your best potential vision with all types of lens implants.

Posted on January 22, 2018 .

What is a cataract?

Patients are always surprised when shown a photograph of their own cataract, but then understand why it is that they don't see well. The natural lens is like a large Smarty or M&M - essentially a lens made of protein. When young this is completely clear, but with age the protein becomes hazy, yellow or brown. This change is called a cataract. As the person with a cataract looks through this murky material their vision is also blurred as a result. 

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A yellow-brown cataract can be seen in the centre of the pupil in this recent patient


Cataract surgery removes the cloudy lens and replaces it with a crystal clear artificial lens implant. This lens can correct long-sight, short-sight and even astigmatism. Sophisticated lenses such as the trifocal lens implant can allow patients to read without glasses.

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The trifocal lens implant gives patients independence from glasses

Contact us if you'd like to find out more about achieving your best potential vision if you're having cataract surgery.

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Posted on October 2, 2017 .

Mr Angunawela is part of the team to win a National Patient Safety Award

Mr Angunawela is part of the winning team from Moorfields Eye Hospital that won a National Patient Safety Award on the 4th of July. The prestigious prize was awarded in the category for governance, risk management and patient safety and highlights the hospital's dedication to ensuring the best standards of care for its patients and its position as the leading eye hospital in the UK. The prize is competitively awarded nationally and across all medical specialities.

Patient safety awards

Mr Angunawela was the first to recognise a rare complication of drops prescribed after routine cataract surgery leading to loss of vision in some patients. This led to a focused team effort by doctors, pharmacists and risk management experts to address this issue resulting in a national alert trigger when the same combination of drops are prescribed anywhere in the country and no further complications reported over the last year since the problem was first recognised.

patient safety
patient safety award
Posted on July 5, 2017 .

Latest generation corneal collagen crosslinking for keratoconus

We're excited to be able to offer the latest Avedro Mosaic custom corneal collagen crosslinking using precise eye tracking to deliver treatment to the weakest part of the keratoconic cornea. This technology can significantly improve the overall shape of the cornea and improve vision. Moorfields Private is the first clinic in the UK to offer this state of the art technology to patients.

Posted on June 27, 2017 .

PTK laser improves vision in Reiss-Buckler corneal dystrophy

Reis-Buckler dystrophy

Reis-Buckler Corneal Dystrophy

This is a relative rare corneal dystrophy where a material is deposited under the surface of the cornea. As this material collects the persons cornea becomes frosty and hazy resulting in reduced vision.

This 21 year old patient had PTK excimer laser treatment to clear a central window in the corneal deposits to allow her to see. The results were almost instantaneous. 

Posted on June 26, 2017 .