Cataracts
What a cataract is, how it's diagnosed, and your options for treatment.
What is a cataract?
A cataract is the last stage of the natural ageing process that affects the lens in the eye. When we are young, the lens is transparent and quite pliable, so it can change shape to help us focus on things clearly in the distance as well as up close, such as for reading and using mobile phones and tablets.
As we get older, the lens becomes less flexible — this is called presbyopia, and reading glasses help with near vision. Over the years your reading prescription changes; the lens is still clear at this stage. Later, the lens starts to thicken and affects distance vision too, so people who never needed glasses for driving or watching TV may need bifocals or varifocals — but vision is still clear with glasses.
Finally, the lens becomes yellowed and opaque: this is a cataract. Vision becomes dull and hazy, and glasses no longer help as much. Your optician may then advise you to consider cataract surgery to regain clear vision.
Do I have to have cataract surgery?
You can have cataracts but be managing well enough for your needs, and put off surgery until things become less clear. You may notice difficulty with dim lighting, recognising faces or bus numbers at a distance, night driving, or glare from oncoming headlights. If you've had a recent fall, it's important your doctors establish whether poor vision from cataracts contributed.
Questions Rahila usually asks
- Are you having difficulty seeing the TV screen or reading subtitles?
- Are you struggling to recognise bus numbers or faces until people are close?
- Is reading small print difficult unless lighting is very bright?
- Has your optician said a new glasses prescription can't improve your vision?
- Do you have glare with night driving or in bright lights?
- Is your vision affecting your work or a hobby you enjoy?
It's fine to leave cataract surgery and rely on your better eye for as long as you're comfortable, unless the cataract is advanced with severe vision loss. If you're a driver and your vision doesn't meet DVLA standards, surgery is usually recommended if you wish to continue driving.
What does cataract surgery involve?
Cataract surgery is usually done as a day case under local anaesthetic — drops or an injection to numb the eye — though sedation or general anaesthesia can be arranged for anxious patients. You'll have dilating drops beforehand and lie down for the procedure, performed through an operating microscope with a drape over the other eye.
Most patients don't need stitches, though occasionally one is placed to secure a leaking wound. At the end of surgery you'll have a clear plastic shield over the eye to reduce the risk of accidentally rubbing it.
Your choices for lens implant outcome
When the natural lens is removed, it's replaced with an artificial lens implant (IOL). We'll discuss which visual outcome suits you — glasses for near vision, or reduced spectacle dependence overall with a multifocal lens.
Lens implant options
Single focus lens
Clear distance vision with reading glasses for near (most common choice), or unaided near vision with glasses for distance, for those with specific reasons to prefer this.
Monovision
Standard lenses set for clear distance in one eye and clear near in the other. Suits people already comfortable with this from contact lens wear; you may still need glasses for the clearest distance or detailed near vision.
Toric lens (astigmatism)
Recommended when there's significant astigmatism, for the best visual outcome with reduced spectacle dependence. Requires extra pre-surgery tests and a specially ordered lens. Not all insurers cover toric lenses — please check your policy.
Multifocal lens
Clearer vision for both distance and near. Not suitable for everyone — possible glare and halos at night, and some loss of contrast. Not recommended if you've had previous macular problems.
What are the risks of cataract surgery?
Risks are low and in most cases manageable with good visual outcomes, but no procedure is without risk and no surgeon can guarantee an outcome. Factors such as previous vitrectomy, high myopia, small pupils or dense cataracts can increase risk, and Rahila will discuss any relevant factors with you before surgery.
Infection (endophthalmitis)
Rare, generally within the first week. Watch for increased pain, redness, or blurred vision and seek prompt advice.
Bleeding
Less common with modern small-incision surgery, more relevant in highly myopic eyes or those with previous vitrectomy.
Ruptured posterior capsule
Usually managed at the time of surgery, though it may mean a toric or multifocal lens can't be implanted.
Retinal detachment risk
Slightly increased after any lens surgery. Be aware of new floaters, flashing lights, or a shadow/curtain in your vision afterwards.
Macular oedema
Swelling at the macula some weeks after surgery, causing blurred or distorted vision. More common in people with diabetes; drops are prescribed to reduce this risk.
Refractive surprise
Rarely, the visual outcome differs from what was predicted. Usually the vision adjusts; very rarely the lens implant needs exchanging.
Further reading: Royal College of Ophthalmologists — cataract surgery.