Understanding cataracts: An expert answers your questions

Written by: Mr Scott Robbie
Edited by: Sophie Kennedy

Being diagnosed with a condition that affects your vision can be a worrying experience. Cataract is a very common clouding of the eye’s lens that affects most people as they age. In this informative article, highly respected consultant ophthalmologist Mr Scott Robbie expertly answers commonly asked questions about the condition, including the causes behind cataracts and their effects on our vision. The renowned specialist also details what patients should expect from surgery to treat cataracts.



How do cataracts affect our ability to see?


Cataracts can affect our eyes in different ways as there are various forms of the condition. Generally speaking, however, all types of cataract degrade the quality of the image that is presented to your retina at the back of the eye. If you imagine the lens of a camera that is a little cloudy, even though the quality of image is affected, you are still able to see something.


A lot of patients don't really notice that they have cataracts and the effects may present themselves as glare or difficulties driving at night. Other cataracts might drive a change in your glasses prescription which may lead your optometrist to pick up on the problem. Otherwise, you might notice that you're having more difficulty with reading, for example; so cataracts can affect your vision in multiple ways.


Bearing in mind that cataract is essentially a clouding of the lens, this can bring about a yellow-ish discolouration. This means that colours may appear less vivid or may be tinted slightly yellow. As these changes occur over time in most patients, they're not usually aware of them until after their surgery has been completed, where the quality and clarity of vision come flooding back with brand new lenses in place.



Are cataracts genetic?


Cataracts can be genetic, but by far and away the most common cause of cataracts is ageing and so they are one of the natural consequences of a long life. Cataracts do run in some families but these patients make up a very, very small percentage of the overall number of those who experience the condition. In patients who are affected genetically, cataracts tend to develop sooner and are more noticeable at a younger age. Treatment approaches for such patients may differ slightly from typical cataract treatment in older patients.



What causes cataracts to develop?


The fact of the matter is that ageing affects us all eventually. The natural lens in the eye, known as the crystalline lens, is also affected by this process when the tiny protein molecules within it become clumped together. These molecules are like building blocks which make us what we are. In the lens they are arranged in a very careful way by the body to be transparent and to focus light, allowing us to see clearly. Over time, these proteins are damaged and consequently they begin to aggregate and scatter light as it passes through the lens. This damage can be caused by various things, including ultraviolet radiation which is a natural consequence of being exposed to sunlight over the course of our lives.


When the light scatters, the quality of the image of the back of the eye becomes affected. We recognise this as blurring, glare or difficulties with reading and so forth. Mostly, cataracts are caused by ageing. However there are some systemic conditions or contexts which can cause cataracts to develop or accelerate their progression, including:

  • conditions such as diabetes
  • smoking
  • trauma to the eye
  • previous surgery inside the eye


Some patients suffering from inflammatory conditions that affect the eye require steroid drops or steroid taken orally. Unfortunately, this type of treatment has some potential side effects including raising pressure in the eye and an elevated risk of cataract, especially if the steroid is of a high potency or the treatment has been administered for many months or years.



Can cataracts develop in people who are considered to have good eyesight?


Cataracts can certainly develop in people that have good eyesight. With ageing, even those who regard their eyesight as very good will likely notice some deterioration over time and may go on to use reading glasses, for example. This type of deterioration, known as presbyopia, is rather different to cataracts. It occurs particularly in our forties and fifties because the lens in the eye is not as good at changing shape to focus light for near vision as it once was. With cataracts, however, the lens actually becomes cloudy.



When is cataract surgery suggested?


There are two categories of patients that might undergo a cataract surgery procedure. Some patients, usually in their forties and fifties, elect to go in for a cataract surgical procedure even if they are not suffering from the condition. They often choose to undergo this procedure because they no longer wish to rely on reading glasses or spectacles of any sort. Removing the lens, even though no clouding has occurred, and replacing it with a clear plastic lens is one way of tackling the problem.


Most of us will get to a point where we find that the effects of ageing on the lens troublesome because of the poor quality and clarity of the image it provides. The only treatment for cataracts is surgery. Fortunately, this is now a very highly refined procedure because of the technological improvements in the last fifty years. Surgery for cataracts has evolved to such an extent that the risks are much lower now than they have ever been. The impact of the sorts of lenses available has also vastly improved surgery for cataracts. Premium lenses give us much more flexibility in targeting and tailoring outcomes for individual patients.



How is surgery for cataracts performed?


Cataract surgery can usually be performed a day case procedure. On arriving at the hospital or eye unit, patients are given some drops to dilate the pupils which may make vision temporarily a little blurry. Anaesthetic drops are also administered. Additionally, we have the option of putting anaesthetic in the front chamber of the eye or bathing the eye in anaesthetic to numb the whole area.


The surgery itself involves making some very small incisions in the clear part of the front of the eye, known as the cornea, in order to gain access to the lens. The lens can then be removed using ultrasound by breaking it up and aspirating it. Following this, thanks to advances in lens technology, we're able to introduce the new, artificial lenses through the same small incisions. The new lens folds into what is called the capsular bag of the lens, which is preserved during surgery. With the new lens in place, your eye is then able to focus the light correctly.


The artificial lenses inserted during cataract surgery can remain in place going forward, usually without any need for revision. As with any surgical procedure, there is a very small risk of infection, retinal detachment or bleeding, but this occurs in less than one in a thousand cases. Even if a serious complication occurs, it is usually possible to reduce the risk of permanent visual loss if managed early and appropriately.


After a year or two, in around ten per cent of cases, a further procedure is required to clear the vision again because of some clouding that can occur in the bag that holds the lens. This is done in a low risk procedure that involves using a laser to break up a membrane that thickens up and becomes more opaque over time. It may be required more frequently in those opting for premium lenses to reduce their dependence on glasses.



What advice would you give to patients receiving a diagnosis of cataracts?


Firstly, I would reassure not to panic because cataracts is a very common condition and as such, cataract surgery is the most commonly performed operation in the world. The second important thing to consider is that you will want to ensure you see an optometrist or a GP to get referred to an ophthalmologist who will assess the eye in more detail and perform any investigations that are necessary.


There are some advantages to seeking out private treatment for cataracts, such as personally choosing your surgeon as well as the day and time of your procedure. There may also be some options available in the private sector that aren’t offered within the NHS, including lens options that may reduce your dependence on glasses.




If you are seeking treatment for cataracts and would like to discuss you options further, don’t hesitate to book a consultation with Mr Robbie by visiting his Top Doctors profile.

By Mr Scott Robbie

Mr Scott Robbie is a renowned consultant ophthalmologist at Guy’s and St. Thomas’ Hospitals specialising in cornea, cataract, external diseases and refractive surgery. He has over 15 years of experience in ophthalmology with over 3000 cataract surgeries performed.

Mr Robbie trained at Moorfields Eye Hospital NHS Foundation Trust where he completed two years of advanced corneal surgical training and a further two years as a consultant in cornea, cataract and external diseases before joining the team at Guy’s and St. Thomas’ in 2017. He obtained further experience as a visiting consultant at University of Iowa Hospitals in the United States in 2015. Mr Robbie also has a PhD in Genetics, undertaken at the world-renowned UCL Institute of Ophthalmology, where he was involved in the first gene therapy trial for an eye condition and engaged in collaborations with GlaxoSmithKline and the University of Bristol, amongst others.

As a prestigious National Institute for Health Research Clinical lecturer at Moorfields, he obtained funding to develop a translational project examining the use of gene therapy viral vectors to treat corneal neovascularisation and, to this day, he continues to work on this as a research associate at University College London. He has more than 30 peer-reviewed publications to his name. 

One of the highlights of Mr Robbie's career is that he was selected as one of the eye surgeons responsible for providing care to athletes in the Athlete’s Village at the London 2012 Olympics and Paralympics. He maintains a broad research interest that encompasses novel therapeutics and intraocular lens technologies, most recently lens technology developed to improve visual outcomes in patients with macular disease undergoing cataract surgery.

His wealth of expertise and dedication to the field of ophthalmology has led him to be a key figure in the teaching and training of many junior doctors and medical students. He regularly trains other surgeons in cataract and corneal surgery in the NHS.

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