Intraocular lenses are used to treat cataracts, a condition that causes poor vision due to clouding of the natural lenses in your eyes.
Your natural lenses are usually clear and focus light that enters your eyes onto the light-sensitive tissue at the backs of your eyes (your retina), allowing you to see. With age, your natural lenses develop cloudy patches (cataracts). Cataract removal surgery is used to take out the cloudy lenses and replace them with clear, artificial lenses called intraocular lenses.
Just as the lenses in prescription glasses are designed to enable you to see clearly at certain distances, so too are intraocular lenses. They can be tailored to enable you to see clearly at long or short distances without wearing glasses and can also help correct astigmatism.
Cataract removal surgery, where cloudy lenses are replaced with clear intraocular lenses, is not essential for every individual who develops cataracts.
However, cataracts get worse over time, leading to blurred vision, glare and a reduced ability to see well at night or in dark conditions. This can affect your quality of life and prevent you from legally driving as minimum eyesight requirements must be met. At this point, many individuals consider cataract removal surgery.
Cataract removal surgery is one of the most common surgeries performed in the UK and is generally very safe. However, no surgery is risk-free, which is why if you’re considering it, your ophthalmologist will discuss the pros and cons with you so you can make an informed decision. If you decide to go ahead with surgery, they will also discuss the different options for intraocular lens implants.
On the NHS, only standard monofocal intraocular lenses are available, which allow you to focus well at one distance, usually at long distances. This means after recovering from your surgery, you will be able to see well at long distances but will need to wear glasses for near or intermediate distances. Standard monofocal lenses are also unable to correct astigmatism.
Cataract removal surgery performed privately offers a greater range of intraocular lenses, including toric lenses that correct astigmatism, premium monofocal lenses that offer clear vision at far and intermediate distances, as well as bifocal and trifocal lenses, which allow you to see clearly at several different distances.
However, there are pros and cons to every type of intraocular lens. Trifocal lenses can give you the best chance of clear vision at multiple distances, so you may not need to wear prescription glasses. However, they are prone to glare and rings or haloes appearing around bright lights at night, which means they may not be appropriate if you do a lot of night driving.
The technology behind intraocular lenses continues to advance, with new intraocular lenses coming onto the market. It is, therefore, important to have a comprehensive discussion with your ophthalmologist about which lenses are established as safe and effective and which are most suitable in your case.
Cataract removal surgery takes up to 20 minutes to perform and is a day case, so you can return home on the same day as your surgery. In most cases, you will be awake during your procedure but will have local anaesthesia so won’t feel any pain.
A small cut will be made into your cornea and your surgeon will remove the cloudy lens, usually by breaking it up into small pieces using ultrasound (phacoemulsification). Your new, artificial intraocular lens will then be inserted to replace the old lens.
If you are at low risk of developing complications, your surgeon may recommend having cataract removal surgery in both eyes at the same time. However, if you aren’t comfortable with having surgery in both eyes at the same time, you can stagger your surgeries, often a week apart.
You can expect to be in hospital for several hours so that you can be monitored immediately after your surgery before you are sent home.
Risks of cataract surgery
As with any surgery, there are risks, such as bleeding, corneal or retinal swelling and inflammation. Although in most cases, cataract surgery is successful, around one in 100 people can have worse vision after surgery and around one in 800 develop an eye infection.
Your surgeon will make sure you’re aware of all potential risks before you decide to go ahead with the surgery and further treatment can, in most cases, resolve complications and keep your vision good.
In most cases, the day after your surgery, you will be able to see but may feel like you have something in your eye. You will be given eye drops to use every day for three to four weeks after your surgery and will also be asked to wear an eye shield at night to stop you from rubbing your eyes when you are half-asleep, which you should avoid until you have fully recovered. You should also avoid bending over and lifting heavy objects as this can put pressure on your eyes.
If you wish to return to driving, you will need to meet minimum eyesight requirements set by the DVLA, which include being able to read a number plate from 20 metres away. Most people find they are able to do this a few days after cataract removal surgery, although this can vary.
After your cataract surgery, you may have follow-up appointments to make sure your recovery is progressing as expected and your vision has improved, or you may be asked to see your own optician for an eye exam.
Mr Amar Alwitry is a Consultant Ophthalmologist at Spire Nottingham Hospital specialising in cataract and refractive surgery and glaucoma. He performs over 1,600 cataract procedures every year, has published over 35 research articles and has undertaken specialist training in premium intraocular lens use. He is also a Speciality Advisor to the CQC for Ophthalmology.
If you're concerned about symptoms you're experiencing or require further information on the subject, talk to a GP or see an expert consultant at your local Spire hospital.