Cataract Surgery: What It Is, How It Works and What to Expect

What is a cataract?

The lens of the eye sits just behind the pupil and is normally clear. Its job is to focus light precisely onto the retina at the back of the eye. A cataract occurs when the lens becomes cloudy — progressively opaque rather than crystal clear. This scatters incoming light instead of focusing it, causing the characteristic symptoms: blurred or hazy vision, increased sensitivity to bright lights and glare (particularly from headlights when driving at night), faded or washed-out colours, and the need for increasingly frequent changes to a glasses prescription.

Most cataracts are age-related — the protein structure of the lens slowly changes over decades, causing progressive cloudiness. By the age of 65, the majority of people have some degree of lens opacity, though it may not yet be affecting their vision significantly. Cataracts can also develop following eye injury, as a complication of other eye conditions such as uveitis or glaucoma, after prolonged steroid use, and in babies and young children (congenital cataract).

A cataract is not harmful to the eye in itself, and there is no danger in delaying surgery. The right time to operate is when the cataract is affecting your quality of life — whether that is reading, driving, watching television, or enjoying hobbies — and when the potential benefit of surgery outweighs its small risks.

Do I need cataract surgery?

Surgery is the only way to remove a cataract. Eye drops, dietary supplements, and glasses cannot clear a cloudy lens. However, in the early stages of cataract development, an updated glasses or contact lens prescription may provide adequate vision for several months or years before surgery is needed.

Your ophthalmologist will help you decide the right time for surgery based on your visual acuity, the degree of lens opacity, and most importantly, how your vision is affecting your daily life. You should not feel pressured to have surgery before you are ready — equally, there is no benefit to waiting until the cataract is very advanced.

• Difficulty driving, especially at night (glare, halos around lights)
• Trouble reading or seeing a screen clearly, even with an updated prescription
• Faded colour vision — colours appear desaturated or yellowish
• Double vision in one eye
• Needing significantly brighter light for close work
• Frequent prescription changes that no longer provide clear vision

Preparing for cataract surgery

Before your operation you will attend a pre-operative assessment appointment. This usually takes place 1–4 weeks before surgery. It involves a series of measurements and health checks.

Biometry — precise measurements of the eye's length and corneal curvature — are taken using a specialised scanner. These calculations determine the power of the artificial intraocular lens (IOL) to be implanted, and are critical for achieving your target vision after surgery.

You will be asked about your general health, current medications, and any allergies. Most medications can be continued as normal. If you take blood thinners (such as aspirin, warfarin or clopidogrel), your surgeon or anaesthetist will advise whether these need to be paused. If you wear contact lenses, you will be asked to leave them out for several days before biometry, as contact lenses alter the shape of the cornea and can affect measurement accuracy.

Anaesthetic — what to expect

The overwhelming majority of cataract operations in the UK are performed under local anaesthetic. This means you are fully awake but feel no pain in the eye. The local anaesthetic is almost always given as drops — topical anaesthesia — which numb the surface of the eye completely. Some surgeons use a small injection around the eye (peribulbar or sub-Tenon's block) instead of or in addition to drops.

Under local anaesthetic, you will be aware of bright lights, movement and changes in light and shade during the operation, but you will not see any detail of what is happening. You will not feel any cutting or instrumentation. Many patients are surprised by how comfortable and quick the procedure is.

Intravenous sedation can be added if you are anxious, which will make you feel calm and drowsy while remaining cooperative. General anaesthetic is available but is rarely necessary for routine cataract surgery — it carries more risk than local anaesthetic and is usually reserved for patients unable to cooperate with local anaesthetic (for example, very young children or those with severe claustrophobia).

Because local anaesthetic does not require fasting, you can eat and drink normally on the day of your operation.

The cataract operation — step by step

Cataract surgery today is one of the safest and most refined surgical procedures in medicine. The standard technique is phacoemulsification — a word that describes exactly what happens: the cataract is emulsified (broken up) using high-frequency ultrasound vibrations, then aspirated (removed) through a very small incision.

The operation takes approximately 15–30 minutes. You will be lying flat or slightly reclined on an operating table. Your eye and the surrounding skin are cleaned and a sterile drape placed over your face with a small opening over the eye. Eye drops to dilate your pupil will have been given beforehand.

• A tiny self-sealing incision (approximately 2.4–2.8mm) is made in the cornea at the edge of the eye.
• A circular opening is created in the front of the lens capsule (the thin membrane surrounding the lens) — a step called the capsulorhexis.
• A fine ultrasound probe is inserted to break up and remove the cloudy lens contents. The back of the capsule (the posterior capsule) is intentionally left intact — it will support the new artificial lens.
• The artificial intraocular lens (IOL) is folded and inserted through the small incision, then gently unfolded inside the capsular bag.
• The wound is self-sealing and usually requires no stitches.
• A transparent shield is placed over the eye. You can go home within an hour or two.

Intraocular lenses (IOLs) — your choices

The artificial lens inserted during cataract surgery stays in your eye permanently. Choosing the right lens is one of the most important decisions in private cataract surgery — and it is where private surgery offers a significant advantage over NHS treatment.

The NHS provides a standard monofocal IOL, which corrects vision at one distance only (usually distance). Reading glasses are still required for close work.

Private surgery offers a range of premium IOL options:

• Monofocal IOL — corrects distance vision. Reading glasses required for near work. High optical quality, most straightforward adaptation. Suitable for most patients.
• Toric IOL — a monofocal lens with added correction for astigmatism (a focusing irregularity caused by a non-spherical cornea). Reduces or eliminates the need for distance glasses in patients with significant astigmatism.
• Multifocal IOL — designed to provide functional vision at near, intermediate and distance. Can reduce dependence on glasses at all distances. Trade-off: some patients experience halos and reduced contrast sensitivity, particularly at night. Not suitable for everyone.
• Extended Depth of Focus (EDOF) IOL — provides a continuous range of vision from distance to intermediate, with less glare than true multifocals. A good option for patients who prioritise computer work or intermediate vision alongside good distance.
• Monovision — one eye corrected for distance and the other for near, using monofocal lenses. Can reduce spectacle dependence without premium lens trade-offs. Requires a period of neural adaptation.

Recovery after cataract surgery

Recovery from cataract surgery is generally quick and straightforward. Most people notice a significant improvement in vision within 24–48 hours, though it may take up to 4–6 weeks for vision to fully stabilise as the eye heals.

You will be prescribed antibiotic and anti-inflammatory eye drops to use for 4–6 weeks post-operatively. It is important to use these as directed — they reduce the risk of infection and control inflammation as the eye settles.

• Vision: often markedly improved within 24–48 hours. Colours may appear brighter and more vivid immediately after surgery.
• Driving: you can drive once vision in both eyes meets the DVLA minimum standard (6/12 in the better eye, 6/9 binocularly if driving commercial vehicles). This is typically days to weeks after surgery, once drops have been assessed at your follow-up appointment.
• Screens and reading: you can use your phone, tablet or computer the day after surgery.
• Showering: avoid getting water in the eye for one week. No swimming for four weeks.
• Exercise: light walking and daily activities from the next day. Avoid contact sports, heavy lifting (anything that causes straining or breath-holding) for four weeks.
• Eye rubbing: avoid rubbing or pressing on the eye for at least two weeks.
• Glasses: your existing glasses prescription will no longer be correct after surgery. Wait until your vision has fully stabilised (typically 4–6 weeks) before having a new prescription dispensed.

Risks and complications of cataract surgery

Cataract surgery is very safe — the overall rate of serious complications is less than 1–2%. However, as with all surgery, complications can occur and it is important to understand them.

The most serious risk is endophthalmitis — infection inside the eye. This is rare (affecting approximately 1 in 1,000 cases) but can threaten vision if not treated promptly. Symptoms are sudden onset pain and dramatically reduced vision in the days after surgery. This is a medical emergency requiring immediate contact with the surgical team.

• Posterior capsule opacification (PCO): the most common 'complication' — affecting up to 20–30% of patients within 5 years. The back of the capsule that supports the IOL becomes hazy, causing blurred vision to gradually return. Easily treated with a painless 10-minute outpatient laser procedure (YAG capsulotomy).
• Posterior capsule rupture: the back of the lens capsule can tear during surgery (approximately 1–3% of cases). Usually manageable at the time, but may affect the final visual outcome or require a different approach to IOL placement.
• Raised intraocular pressure: eye pressure can temporarily increase after surgery. Usually resolves with drops. Patients with pre-existing glaucoma require close monitoring.
• Cystoid macular oedema (CME): swelling of the central retina after surgery. Usually treated with anti-inflammatory drops and resolves completely, though it can temporarily reduce vision.
• Retinal detachment: slightly increased lifetime risk following cataract surgery. Symptoms — sudden floaters, flashes, or a curtain across vision — require urgent assessment.
• Corneal cloudiness (decompensation): rare, particularly in patients with pre-existing corneal disease.
• Incorrect IOL power: vision may be over or under-corrected. Usually managed with glasses, though IOL exchange is possible if significant.

NHS vs private cataract surgery — what is the difference?

Both NHS and private cataract surgery use the same surgical technique (phacoemulsification) and the same standard of sterile theatre environment. The key differences are around access, choice and continuity.

NHS cataract surgery is free at the point of care and is of high quality — the UK NHS has a strong track record for cataract outcomes. However, waiting times from GP referral to surgery are typically 6–18 months. NHS patients receive a standard monofocal IOL; premium lens options are not funded.

Private cataract surgery offers significantly faster access (typically 2–4 weeks from consultation to surgery), the full range of IOL technologies (toric, multifocal, EDOF), dedicated pre-operative biometry planning, and named-consultant care throughout. You will see the same consultant for your consultation, surgery, and follow-up.

Considering private cataract surgery in Yorkshire?

Mr Mohamed Mohyudin is a Consultant Ophthalmic Surgeon with over 5,000 personally performed cataract operations. He is a substantive NHS Consultant at Calderdale and Huddersfield NHS Foundation Trust and offers private cataract surgery at Spire Elland Hospital, Elland, West Yorkshire (near Huddersfield, Halifax and Bradford).

Private consultations are typically available within 1–2 weeks. No GP referral is required for self-pay. Mr Mohyudin is Bupa Fee-Assured and recognised by AXA Health, Aviva, Vitality, WPA and all major UK insurers.

To book a consultation, call Spire Elland Hospital on 01422 324000, or visit the booking page on the Spire website.