Is it safe to have cataract surgery on both eyes at the same time? Advantages, risks and who it suits

One of the most common questions I hear in clinic is whether both eyes can be done on the same day. In the UK the traditional pattern has been to operate one eye first, review it a week later, then do the second. That model is safe and well understood — but for the right patient, immediately sequential bilateral cataract surgery (ISBCS), commonly called 'same-day both eyes', is now supported by strong international evidence and delivered routinely in leading private centres.

This piece explains what the surgery involves, what the published safety data actually shows, what the practical advantages are, and — just as important — who I do not recommend it for.

What 'same-day both eyes' actually means

In ISBCS the two eyes are treated as two separate, fully sterile operations performed one after the other in the same visit. Each eye has its own instrument set, its own batch of intraocular fluids, its own intraocular lens (IOL) and, critically, its own intracameral antibiotic. The theatre is fully re-prepped between eyes. It is not 'one operation on two eyes' — it is two individually complete operations, back to back.

You go home the same afternoon with a clear plastic shield taped over each eye for the first night, and you start drops in both eyes that evening.

The evidence on safety

The concern that historically kept UK surgeons cautious was the fear of bilateral endophthalmitis — a devastating infection affecting both eyes at once. Modern evidence has largely answered that concern:

- The International Society of Bilateral Cataract Surgeons (iSBCS) registry, covering hundreds of thousands of ISBCS cases worldwide, has recorded no confirmed cases of simultaneous bilateral endophthalmitis when strict aseptic separation and intracameral antibiotics are used.

- Large cohort studies from Finland, Sweden, Canada and Spain — where ISBCS has been routine for over a decade — show visual outcomes, refractive accuracy and complication rates that are statistically indistinguishable from delayed sequential surgery.

- The Royal College of Ophthalmologists' current guidance recognises ISBCS as an acceptable option in appropriately selected patients, provided the two eyes are treated as fully independent procedures.

The single most important safety rule is patient selection. Bilateral surgery is only offered when both eyes are anatomically straightforward, biometry (lens power measurement) is highly reliable, and there are no risk factors that would make me want to see how the first eye behaves before operating on the second.

The advantages — why patients ask for it

For the right person the practical advantages are real:

- One recovery, not two. You use one block of time off work, one course of drops, one set of restrictions on driving, swimming and heavy lifting. Most patients are back at a desk within 3–4 days rather than repeating that pause a fortnight later.

- Faster balanced vision. After single-eye surgery there is usually a 1–2 week gap where one eye is corrected for distance and the other is still cataractous or short-sighted. That mismatch (anisometropia) can cause imbalance, headaches and difficulty judging steps. ISBCS eliminates it — both eyes clear together.

- One anaesthetic exposure. Particularly valuable for patients who are anxious, who have needle phobia, or who need sedation. It also matters for frail patients and those who have travelled a long distance or from overseas for surgery.

- One theatre fee, one anaesthetist fee. In private practice ISBCS is typically 10–20% cheaper than two separate procedures because much of the fixed cost of a theatre session is only paid once.

- Better for premium lens patients. Multifocal and extended-depth-of-focus (EDOF) lenses are designed to work as a pair. Operating both eyes on the same day gets you to the finished visual result — and to the brain's neural adaptation to the new optics — in days rather than weeks.

Who I recommend it for

In my clinics I typically offer ISBCS to patients who:

- Have straightforward, age-related cataracts or clear-lens exchange in both eyes

- Have healthy corneas, normal axial lengths and reliable biometry with the Zeiss IOLMaster 700

- Have no diabetic retinopathy, macular disease, glaucoma or previous refractive surgery complications

- Have a supportive adult at home to help with drops and daily tasks for the first 48 hours

- Are choosing premium lenses and want the fastest route to balanced binocular vision

- Are travelling from outside the UK and cannot easily return for a second visit

Who I recommend against it for

I actively steer some patients towards the traditional one-eye-at-a-time pathway:

- Only-eye patients, or very asymmetric prescriptions where the calculation of the second lens should be adjusted based on how the first eye actually settles

- Complex cases — dense white cataracts, previous vitrectomy, uveitis, pseudoexfoliation, small pupils, floppy iris syndrome

- Anyone at higher infection risk: active blepharitis, untreated dry eye, immunosuppression, poorly controlled diabetes

- Patients who live alone with no support at home for the first 24–48 hours

- Patients who feel more comfortable knowing the first eye is fully healed before committing the second — that instinct is legitimate and I always respect it

What recovery looks like

The photograph on this article shows what patients typically look like on the evening of surgery: both eyes shielded, comfortable, resting at home. Practical points for the first 48 hours:

- Shields on both eyes overnight, and for daytime naps, for the first week

- Drops in each eye four times a day, on the exact same schedule

- Vision is blurry and light-sensitive for the first evening and the following morning; by day 2 most patients are watching TV comfortably and reading larger print

- You will need someone to bring you home and stay overnight

- No driving until I confirm you meet the DVLA standard, usually at the day 7–10 review

- Both eyes are reviewed together on day 1 and again at 1–2 weeks

For a full picture of the recovery arc, my cataract surgery recovery day by day guide applies to each eye — the timeline is the same, it just runs in parallel rather than sequentially.

Cost and how to decide

Bilateral lens replacement in my private practice starts at £2,750 per eye for monofocal lenses and rises with premium multifocal, EDOF and toric lenses. The consultation, biometry, both procedures and all post-operative reviews are included in the quoted fee — there are no separate anaesthetist or facility charges. See lens replacement cost UK for the full breakdown.

The decision between same-day bilateral and staged surgery is a clinical one — it depends on your scans, your general health, your lifestyle and your personal preference. I will not push you either way. In my consultations we look at the biometry together, walk through the pros and cons for your specific eyes, and agree the plan you feel most confident with.

Next steps

If you would like to discuss whether same-day bilateral cataract or lens replacement surgery is right for you, we run consultations across 17 UK clinics and offer a full diagnostic workup — including Zeiss IOLMaster 700 biometry, corneal topography and macular OCT — at the initial visit. You can book a consultation online or call 020 3137 3237.