Cataract surgery: both eyes on the same day or on different days?

People who need cataract surgery on both eyes may wonder whether it is better to have them done on the same day or on different days. In this blog, Sarah Chapman looks at the Cochrane evidence on how the two approaches compare and discusses what else might be important to consider.

There is a shorter version of this blog – Cataract surgery: a quick look. Both blogs have links to useful information for patients. Stay on this page if you would like a bit more detail and discussion.

Take-home points It is very common for people to develop cataracts, often in both eyes, as they age. These can be treated by surgery to remove the cataract and replace the cloudy lens of the eye with a clear plastic one. A Cochrane Review comparing the safety and effectiveness of operating on both eyes on the same day or on different days suggests “there are probably no clinically important differences in outcomes” between the two approaches. Same day surgery, which saves time and resources, is becoming more common in the UK. NICE guidelines recommend considering it for people at low risk of eye complications. Personal preferences and priorities are important when making treatment choices. These might include your feelings about more/fewer hospital visits and one operation versus two, as well as considerations around recovery from surgery and disruption to your usual activities.

Cataract surgery seems to me a remarkable thing. In under an hour, it’s out with the old lens, in with the new, and off you go. All being well, you’ll soon be enjoying good vision – perhaps the best it’s been for a very long time. At least, those of us with access to this surgery will…*

Here in the UK, cataract surgery is available on the NHS, though some people pay to have it done privately. I know lots of people who have either had cataracts removed or are on a waiting list for surgery, and this is unsurprising. Many of us develop them as we age, often in both eyes, with factors such as eye injury, diabetes, smoking or too much alcohol, or a family history of cataracts increasing the risk.

What is a cataract?

A cataract is a clouding of the lens of the eye, affecting the vision. It gets worse over time and, if a change to your glasses prescription is no longer enough, then surgery is needed to replace the cloudy lens (the cataract) with a clear plastic one.

You may have heard that the cataract has to become ‘ripe’ or ‘ready’ before it’s removed, but this is no longer true. Technology and techniques have moved on and the surgery is now possible at any stage. Your optician can tell you whether your cataract meets the criteria for removal on the NHS.

It’s usual for cataract surgery to be done under local anaesthetic, so you’ll be awake but won’t feel pain in your eye or the area around it. The cataract is taken out and the new lens put in through a tiny cut. You can read patient-friendly information from the links below, which give clear explanations about cataracts, the operation and what to expect, as well as practical information.

Timing of surgery – two cataracts at once?

When my sister was preparing to have her cataracts removed, I was surprised to hear that she was to have both done on the same day. Soon after, my uncle had his done with some weeks between the first and second eye being operated on, which is the more common approach in the UK. I wondered what the evidence is for how the two approaches compare, and what else might be important to consider.

A recent Cochrane Review, Immediate sequential bilateral surgery versus delayed sequential bilateral surgery for cataracts (April 2022) has brought together evidence that might answer questions about whether operating on both eyes on the same day (Immediate sequential bilateral surgery or ISBS) is as safe and effective as doing them on different days (delayed sequential bilateral surgery or DSBS). The evidence is relevant to people with age-related cataracts.

The bottom line:

“…there are probably no clinically important differences in outcomes” between doing cataract surgery on one eye and then the other on the same day compared with doing them on different days.

A bit more detail:

  • There was little evidence on the risk of infection which is, thankfully, a very rare complication. The review authors say there was a very low risk in both groups. Based on very few cases of infection in one eye, it seems that the timing of surgery (doing two eyes on the same day or on different days) may make little to no difference, but we can’t be sure.
  • There may be little to no difference in other complications, such as bleeding or retinal detachment, either during or after the operation (but again the evidence is very uncertain).
  • There is probably little to no difference between the two in visual outcomes, one to three months after surgery.
  • There was probably little to no difference between the two in the answers people gave in questionnaires after surgery. The questionnaires asked about visual function and patient satisfaction with vision.

Same-day surgery saves time and money

The Cochrane Review can’t tell us about this but, in terms of resources and convenience, one visit has distinct advantages over two. The pandemic gave same-day surgery a boost, with surgeons being encouraged to offer it to those suitable for it, given the advantages of reducing hospital visits and using services more efficiently (Healey, 2021).

For patients, same-day surgery means fewer hospital visits and only one post-operative recovery period – so less time off work or away from other activities and less time needing help at home after surgery. For people with cataracts in both eyes, they stand to gain more from having them done together, as their vision after surgery will be better than during a period of waiting for the second cataract to be removed. This also avoids the increased risk of falls that is associated with the period between a first and second cataract operation. For the few people who need to have a general anaesthetic (such as some people with learning difficulties or dementia), a single operation exposes them to the associated risks once rather than twice.

However, in the NHS, it seems that the way payment works is a disincentive to give patients the option of having both eyes operated on together. According to Consultant Ophthalmic Surgeon Professor David Spalton at St Thomas’s Hospital in London, speaking in 2021, “If you do two operations, you get paid for two operations. If you do it as bilateral, you usually get paid about one and a half.” (Healey, 2021).

Is same-day cataract surgery more risky?

Surgeons are divided about the balance of risks and benefits for same-day surgery. Some say the risk of infection in both eyes is unacceptable. But the chances of this rare complication are reduced by measures such as using antibiotics during surgery and treating each eye as if they belong to two different people – for example, using fresh equipment and different batches of fluids for each.

Although delaying the second operation enables the surgeon to check the results of the first before doing the second eye, doing one and then immediately the other means the surgeon has information from how the first eye behaved during surgery that may be helpful as they do the second.

In the UK, the NICE guideline Cataracts in adults: management (October 2017) says same-day surgery for both eyes should be considered for people who are at low risk of eye complications, and for some people who need to have surgery done under general anaesthetic.

In the Netherlands, where current guidelines do not allow same-day surgery on both eyes, a multi-centre randomised controlled trial is in progress to compare the two approaches (O’hEineachain, 2021). Preliminary results show “comparable safety and effectiveness” for same-day versus delayed second eye surgery. Let’s hope that when the Cochrane Review is updated, this and other studies will be available to add to the evidence.

What’s important to you?

 There are three key elements to making choices about any health treatments:

  • what your preferences and priorities are
  • clinical expertise
  • information from the best available evidence, including an awareness of where there are uncertainties about the effects of treatment

This can be a useful basis for discussing options with a healthcare professional involved in your care.

You can ask your ophthalmologist (eye specialist) whether having both cataracts operated on at the same appointment is an option for you. They will discuss any considerations, including the risks and how these apply to you.

If you are given the choice between having two eyes done on the same day or at different appointments, given that the available evidence shows there is probably little to no difference in visual outcomes and safety, then other considerations may be deciding factors. These may include your feelings about having one operation and recovery period versus two, the resources available to you (such as help at home while you recover) and the impact on your usual activities, such as driving, work, or care responsibilities.

Find out more

*As with so much else, enormous regional inequalities exist. More than 90% of people with visual impairment due to cataracts live in low- and middle-income countries, where access to this relatively simple and cost-effective treatment is often restricted.

Join in the conversation on Twitter with @CochraneUK @SarahChapman30 or leave a comment on the blog.

Please note, we cannot give specific medical advice and do not publish comments that link to individual pages requesting donations or to commercial sites, or appear to endorse commercial products. We welcome diverse views and encourage discussion but we ask that comments are respectful and reserve the right to not publish any we consider offensive. Cochrane UK does not fact check – or endorse – readers’ comments, including any treatments mentioned.

References (pdf)

Sarah Chapman has nothing to disclose.

Cataract surgery: both eyes on the same day or on different days? by Sarah Chapman

is licensed under a Creative Commons Attribution-NoDerivatives 4.0 International

18 Comments on this post

  1. I had major problems after having both eyes operated on immediately after each other on the same day. I would like to suggest there is a great advantage to have a gap of time to monitor reactions to severe hypersensitivity to eye medications used pre op, during op and post op, when having both eyes operated on the same day. Hi my name is Susan and I live in New Zealand. My operation was done privately. I paid over $12,000 to have this operation. In my case there was no gap or rest time between eyes being operated on. Just as the second eye was being finished my first eye began to sting. I was told that was normal. By the time I was out of theatre and sitting waiting to b picked up – the pain was excruciating in my first eye operated on. It felt like intense searing burning and stinging. 9/10 on pain scale. It felt as if I had had acid poured into my eye. My sensitivity to light was also intense. I couldn’t couldn’t open my eyes – the excessive intolerance to light was felt through my closed eyelid. I asked for a towel to be put over my head to keep out the light. The surgeon was called and checked me. I was still in the clinic waiting to b picked up and driven home. Both eyes were streaming with tears even tho at that stage only one eye was very painful. The surgeon added more anaesthetic drops to that eye. This gave immediate but short term relief. He also put a pressure bandage over both eyes “to stop them from moving”. This didn’t help. I was sent home. Soon after leaving the clinic my other eye became excessively painful too. The pain was intolerable. To cut a long story short – 12 weeks and a lot of ongoing but extremely slowly decreasing pain later – my eye pain and burning is settling very well. My vision is so much better than it was but my journey has been a nightmare. Although rare – it is obvious I have a hypersensitivity to the eye medication drops given directly before my operation as well as the ongoing medications eye drops post surgery. Most eye drops have the same preservative benzalkonium chloride. I understand it is rare – but it is already established some of us can have a reaction to this preservative. Having five drops of different medications pre op is most likely to b the cause of the excessive pain and burning to both of my eyes. Both the steroid and the moisturising eye drop prescribed for post op use have this same preservative. Each subsequent application of the ongoing drops caused two to three hours of greater eye redness, swelling, pain and great amount of burning. I understand some momentary staining is common. My reaction to each drop was 2-3 hours with each drop. This tended to settle down just a little before the next application of the drops. At 9 weeks op: Almost two days after I was told to abruptly stop using the steroid (at 9 weeks) it was a great relief my eyes became free of much of the pain and irritation apart from some much milder residual burning that was also decreasing. Although the sclera ( white portion of the eye ) remained a little more red than it was pre- op. After a almost two days of great relief I experienced re-bound potentially due to the abrupt stopping of the steroid drops – instead of ‘tapering off’ the steroid as advised by the pharmaceutical information on this steroid.
    Subsequent recent examination (at 12 weeks post op) by a different specialist determined the surface of my eye has a great number of healing abrasions. This severe reaction to meds/preservative is rare. But when it happens it is debilitating for many weeks – if the ongoing medication is cause of the symptoms. But I feel this excessive and very long term pain burning and distress could have been avoided in my second eye – had there been a space of time between the same day eye operations to monitor the eye for adverse reactions to the eye drops. Maybe it is possible to pre-test for hypersensitivity to the different eye drops that are to be used during and after surgery? I hope this account of my experience can help ensure others don’t go through a similar experience.

    Susan / Reply
  2. I have just had cataract surgery on both eyes at the same time.
    I hope my experience will help others.
    Basically do your homework, read all you can and ask your questions
    Make sure you are confident with this knowledge and also with the surgeon. Once you are armed with this you will feel much more at ease.
    I found the surgery difficult, but not painful. Probably because I’m a bit sensitive to anything to do with my eyes.
    I was vigilant with the eye drops as I am not able to have antibiotics, so it was important not to get an infection.
    I also really made sure I stayed away from people to avoid risk of colds etc
    So now I await my check up a month later. From my perspective it has been an enormous success. I have wonderful vision and the world is so much brighter.
    On reflection I would have both eyes done again together, without a doubt.
    Hope this helps someone to make that important choice

    Roberta Minty / Reply
    • Roberta, may I ask if you have the option available to you in the UK, to choose which lens you receive? What I mean by that is in Canada, if you are unable to afford the bifocal/progressive type Intra ocular lens, the government will pay for a single vision lens which means you may/will then need reading glasses at the least for the rest of your life.
      IF you can afford the more advanced (expensive lens) then you will have 20/20 vision and not require reading glasses….of course one is not able to say “forever” but that is the hope in receiving the more advanced (expensive) lens(‘S).
      A side not for those wondering….for two lenses it work out roughly to be approximately $5,000 CAD.

      Also when you say “do your homework” I am curious as to what you mean? Do you mean ensure your chosen Doc is in good standing and has great success? Did you ask questions such as “Do you use two separate Surgical trays?” (One for each eye as studies show that treating bilateral cataract surgery as if it were two entirely separate eyes or patients, cut the contamination/infection rate in half-which it sounds like your surgeon would be hyper vigilant with you due to your inability to use antibiotics so that may not have been a concern for you or perhaps it was? I am wondering if you asked that because if I were the Doctor, I might think that would be an insulting question but then again it is the EYES!….. The wheels are spinning most assuredly).

      Almost lastly…..were you told that you would have a “Better outcome by having BOTH done at the same time.”?. It seems to be a repetitive theme with some Ophthalmologists that say that but studies do not show that there is a better outcome…at least not yet……hoping Dr. Chapman and Dr. Cochrane’s study does come out soon…..I just stumbled across them now and say your comments which is exactly what my husband is about to go through. It may be a bit different however as he has gone from +1.00 Diopter to -8.50 in less than 7 months which is incredibly fast and he is only 67 (I never thought I would say “only” before saying “67” 25 years ago!!). Life has thrown us a curveball but as they say, we plan and G-d laughs! So I am doing exactly what you are saying to do….homework…..I just happen to have started with YOU. ♥️

      Insofar as you having bilateral Cataract Surgery (ISBS) how long were you without any sight and unable to drive etc?

      Thank you in advance Roberta. I am so very grateful for any insight (no pun intended!) into your experience as he will be doing bilateral without a doubt due to the speed of these forming.

      Wishing you all the success and continued as well as PERFECT healing!

      Tovah / (in reply to Roberta Minty) Reply
      • Hi again. Wow so many question but I shall cover what I can.
        Today I had my check up and confirm the operation was a great success !! I had no infection, little discomfort and am glad it’s over. The drops 4 times daily, diminishing over the weeks were an inconvenience but not a problem.
        My surgeon suggested the lenses, but said should I wish the alternative to his recommendation, I would have to go elsewhere.
        When I said ‘do your homework’ I meant simply look up the surgeons profile, study it and ask questions via his secretary. . Make sure it is actually Him doing the procedure!! That’s a must.
        I had both eyes done literally one after the other, not on a following day.
        I understand I will now need to see the optician who will confirm if I need glasses for very close work. I can do the supermarket without. As yet I am not driving (my choice) until after the opticians appointment As I mentioned I am extra vigilant.
        You may want to purchase some sunglasses that literally go around and cover the eyes. This is because bright light is harsh and you may need them outside. Plus it will prevent wind travelling to the eyes. You may also wish to get some very low key specs for reading to tie you over.
        Good luck and I hope I’ve been a little help!
        With regards

        Roberta Minty / (in reply to Tovah) Reply
  3. My name is Dawn deisher I been wearing eye glasses along time what year should I get,eye,surgery done in Athens Ohio Iam in my 50 right now thank you

    Dawn deisher, / Reply
  4. There was little evidence on the risk of infection which is, thankfully, a very rare complication. The review authors say there was a very low risk in both groups. Based on very few cases of infection in one eye, it seems that the timing of surgery may make little to no difference.

    Dona Nelson / Reply
  5. I’m in Aotearoa New Zealand and my husband sent me this website. I was quite surprised to learn that my surgeon, whom I have not met, is suggesting doing both eyes on the same day. This is going through a private system which will cost about NZ$8,650. I don’t have an insurance which covers this. Our health system which was recently made into a nationally-run system is in crisis as we don’t have enough doctors or nurses. Many are leaving for higher salaries an working conditions. I feel for those who can’t afford to pay for the operation.

    I’m feeling rather nervous about the operation but my husband, friend and sister have all had successful operations, each eye on a different day.

    Deborah W / Reply
  6. Thanks for this input, it helped me take the decision to have a two-eye surgery next week on the same day!

    Jonas / Reply
    • That’s great to hear! Very best wishes for a good recovery from your surgery.
      Sarah Chapman

      Sarah Chapman / (in reply to Jonas) Reply
  7. I’ve had one eye done and I am waiting for the go ahead for the next one, I would have preferred them done on the same day as having one eye with perfect vision and the other one blurred is not ideal.

    Michael John Gbasai / Reply
    • Thank you for your comment. What a shame you weren’t given the option to have two done together, as that was your preference. I hope you don’t have to wait too long for the second.
      Best wishes,
      Sarah Chapman

      Sarah Chapman / (in reply to Michael John Gbasai) Reply
      • In the USA, Medicare reimbursements to the surgeon ($425) for cataract surgery barely covers the cost to perform the surgery. 30 years ago reimbursement was $2500 – so an 80% reduction with no consideration for skyrocketing increases in supplies, costs, inflation. Reimbursement for the second eye with bilateral surgery is 50% of the price for the first eye. Therefore, the surgeons can actually be losing money. Also, there will definitely come the day when bilateral endophthalmitis will occur. I feel sorry for the poor patient and surgeon that this will happen to! Bilateral blindness will occur. To say it never will is not scientifically supported. Just my 2 cents.

        Phillip Hoopes / (in reply to Sarah Chapman) Reply
  8. My dad had two separate surgery appointments scheduled for cataract and was stressed about overall ‘down time’ and arranging all the travel to appointments and follow ups. I shared the Cochrane Review and this blog post with him. Knowing that there were no clinical outcome differences and he was low risk for complications, he shared then shared the review with his doctor and his preferences and discussed changing his appointments. He was rebooked for both eyes in one visit last week and has had a fast, one-time recovery! Many thanks for helping inform the decision making process with evidence!

    Muriah Umoquit / Reply
    • Thanks so much for sharing this with us, Muriah. We’re so pleased to read about your dad’s positive experience – and how he was able to use the review, and this blog, to help make the best decision for him!

      Selena Ryan-Vig / (in reply to Muriah Umoquit) Reply
  9. My cataract operations were carried out in a private eye hospital but as a NHS patient; at the pre-op consultation my request to have both done at the same time was refused. The hospital administration was most efficient, the staff very competent and the operations on my eyes, twelve weeks apart, successful. The establishment gives the impression of being very successful financially and appears to be one of three such private eye hospitals in the Southampton area. If the clinical evidence as to separate or simultaneous operations is as scant as is suggested above and the payment for performing operations is in the manner quoted at St. Thomas’ then clearly the decision about the pattern of operations is a question of cash-flow and not clinical necessity.

    Roger Hardy / Reply
  10. This is very clear and thorough. Having had two cataracts replaced at two different locations. I have to say, that, in hindsight if I’d been given the opportunity, I would have been happy to have had tgem replaced on the same day….. But because the 2nd location was much more efficient than my local hospital. I was referred to the 2nd location BY the NHS, but the treatment seemed more like private treatment. Having 2 cataracts replaced on the same occasion would have been brilliant, because my sight immediately became so much better.

    Viv Lever / Reply
    • Thank you for taking the time to comment; I’m glad you found this blog clear and thorough. It’s great that you have had a good result from your operations. Hopefully, it will become much more common to offer people the choice to have two done at once.
      Best wishes,
      Sarah Chapman

      Sarah Chapman / (in reply to Viv Lever) Reply
    • I wondered about that. I am going to see a Dr in about 5 hours who does cataract surgeries. Can I get both done in the same day if I live alone? Do Dr automatically 2 different set of instruments for the surgery. My Dr once worked in East London and South Africa. Now he works in Canada.

      Monique Ashby / (in reply to Viv Lever) Reply

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