As we get older, our vision changes and it becomes harder to focus on near objects. This is a natural part of ageing called presbyopia and usually starts in your early to mid-40s. The traditional solution is to get prescription glasses or contact lenses.
If you’re already long-sighted when your presbyopia develops, you’ll need varifocal glasses or varifocal contact lenses. Issues around convenience, comfort and even the ability to change focus with clarity (for varifocal glasses or contacts) can all be challenges. But today, there is an effective alternative — lens replacement surgery.
Before we discuss what lens replacement surgery is, let’s take a closer look at what happens during presbyopia and the signs you can look out for.
As you grow older, the lenses in your eyes become less flexible. This affects your vision because every time you focus on near objects, your lenses need to become more rounded in shape so they can properly focus light onto the back of your eye (retina). With age, as your lenses become stiffer, this gets harder, which makes it difficult to focus on near objects. Tasks you could complete without glasses when you were younger consequently become more difficult.
Signs that you may have presbyopia therefore include having to hold a book, newspaper or food packet further away from you to read it. You may also need to hold your mobile phone further away to read a text message or lean back away from your computer screen when reading your emails.
Lens replacement surgery involves removing your natural lens, which has become stiffer over time, and replacing it with an artificial lens (lens implant). The lens implant is designed to help you see both at near and far distances, so you won’t necessarily need to wear reading glasses for clear near vision.
Before your surgery, detailed measurements of your eye will be taken. Then you’ll be given two sets of eye drops. The first eye drops will widen the pupil of your eye (dilation), making it easier for your surgeon to see your lens. The second eye drops are a local anaesthetic and will numb your eye. This means you won’t feel any pain during your surgery, although you may still be aware of light and movement.
Once your eye is numbed, your surgeon will make a tiny cut on the surface of your eye (cornea) and an ultrasound probe will be used to break up your lens. The lens fragments will be removed with a fine tube and your lens implant will be inserted. No stitches are needed and your eye will be covered with a protective shield.
Your lens replacement surgery will only take 20–30 minutes.
Lens replacement surgery is usually a day case, which means you can return home on the same day as your surgery. However, you will need someone to accompany you home.
You will also need to continue wearing the protective shield placed over your eye after your surgery for a few days, both at night and during the day. You can then switch to only wearing your protective shield at night for another one to two weeks — this will prevent you from rubbing your eye while sleeping.
Although you will need to wear a protective shield over your eye, you can return to your normal activities the day after your surgery. After a few days, when you remove your protective shield, you will be able to see an improvement in your vision.
There are two main types of lens implants available that both allow you to see well over a range of distances: the Multifocal lens (MFIOL) and the Extended Depth of Focus lens (EDoF).
The EDoF lens will give you clearer vision at intermediate and far distances with few disturbances in your vision, such as glare or halos. However, you may still need to wear glasses for reading small print. The MFIOL lens will give you clearer vision at near, intermediate and far distances, also with little glare or halos in your vision.
Your surgeon will advise you on which is most suitable for your situation, factoring in your lifestyle and work. If your work is dependent on night driving, you may need to give extra consideration to the potential for glare created by your lens implant, which could affect your ability to drive safely at night.
As with any surgery, there are some risks involved. However, lens replacement surgery is generally considered to be a low-risk surgery. Potential risks and side effects include:
Cataracts and lens implants
Lens replacement surgery does not cause cataracts and will actually prevent you from developing cataracts in the eye operated on. This is because cataracts form when the makeup of your natural lens changes over time, causing your lens to become cloudy, which blurs your vision. MFIOL and EDoF lens implants do not undergo these changes and therefore do not develop cataracts.
Lens replacement surgery isn’t just used to treat presbyopia, it can also be used to treat short-sightedness (myopia), long-sightedness (hyperopia), astigmatism and cataracts.
Mr David Spokes is a consultant ophthalmologist at Spire Norwich Hospital, specialising in age-related macular degeneration (AMD), cataracts, eyelid cyst surgery and dry eye management. He has undergone specialist training during fellowships at Moorfields Eye Hospital, London, as well as in Perth, Australia and is an active member of the research community in collaboration with the University of East Anglia.