If you’re reading this, you’re probably about to have cataract surgery, you work in eye care, or you’re just trying to understand what the law actually expects when it comes to consent. The word “consent” gets thrown around a lot in medicine, but when you strip away the paperwork and the legal jargon, it’s really about one thing: communication. You and your surgeon need to have a proper, open conversation so you can make a fully informed choice.
This article explores how consent for cataract surgery works in the UK — what your rights are as a patient, what surgeons are legally and ethically obliged to do, and how the General Medical Council (GMC) and UK law define the process. We’ll also unpack what happens when consent goes wrong, how capacity is assessed, and how all of this links back to real clinical practice in busy eye clinics.
So, let’s start from the beginning — what consent really means, and why it’s more than just signing a piece of paper.
What Consent Actually Means in Cataract Surgery
When you agree to have cataract surgery, you’re giving your surgeon permission to perform a procedure on your eye. But that permission has to be informed, voluntary, and given by someone who has capacity. Informed means you understand the benefits, risks, and alternatives. Voluntary means you’re not being pressured. Capacity means you can understand and weigh the decision.
For cataract surgery, this conversation should include the risks (such as infection, inflammation, retinal detachment, or residual refractive error), the expected benefits (improved clarity and quality of vision), and alternatives (doing nothing, waiting longer, or managing with glasses). Surgeons are also expected to explain the uncertainties — because no procedure, even a routine one, is risk-free or guaranteed.
In the UK, consent is not a one-off signature before surgery. It’s an ongoing process that starts when cataract surgery is first discussed and continues right up until the operation itself. This is especially important because many cataract patients are older and may need more time, reassurance, or help processing the information.
The Legal Foundation: The Montgomery Standard
For decades, doctors followed what was called the “Bolam test,” which said that if a doctor acted in line with a responsible body of medical opinion, they were unlikely to be found negligent. But this changed dramatically after a 2015 Supreme Court case called Montgomery v Lanarkshire Health Board.
In that case, a patient wasn’t told about a specific risk that later caused her serious harm. The court ruled that it wasn’t enough for doctors to decide what to disclose based on what their peers would do. Instead, patients have the right to know about any material risk that a reasonable person in their position would want to know — and about any reasonable alternative treatments.
That ruling reshaped medical consent across the UK, including in ophthalmology. Today, surgeons must disclose any risk that could affect a patient’s decision, even if it’s statistically small. For example, the risk of complete visual loss from cataract surgery is very low, but because it’s a life-changing outcome, it must always be discussed.
So, when your surgeon talks through the possible complications, that’s not to scare you — it’s to make sure the decision is truly yours, and that it’s made with full awareness of what could happen.
The Role of the GMC: Guidance for Surgeons
The General Medical Council sets the ethical framework for all doctors in the UK. Its guidance, Decision Making and Consent (updated in 2020), is the reference point for how consent conversations should happen.
The GMC makes it clear that doctors must:
- Listen to patients and understand their goals and values.
- Provide all relevant information about benefits, risks, and uncertainties.
- Support patients to make their own decisions without coercion.
- Check that patients understand the information before proceeding.
For cataract surgeons, this means the conversation should go beyond simply listing complications. It should be about how those risks relate to you — your lifestyle, your vision needs, and your expectations. For instance, a retired person who wants to drive occasionally has different priorities from someone who needs excellent near vision for detailed work.
The GMC also expects surgeons to make sure patients have enough time to ask questions and reflect before signing consent forms. Rushing the process or delegating it entirely to junior staff isn’t acceptable. Consent is the surgeon’s personal responsibility.
Understanding Capacity: When Patients Struggle to Decide
Because cataract surgery often involves older adults, there are times when capacity becomes an issue. Under the Mental Capacity Act 2005, a person is presumed to have capacity unless proven otherwise. But if there’s doubt — say, due to dementia, delirium, or confusion — a proper capacity assessment must be done.
The Act sets out four tests: can the person understand, retain, weigh up, and communicate the decision? If they can, their consent is valid even if others disagree with it. If they can’t, then the decision must be made in their best interests, ideally involving family, carers, or an independent advocate.
For surgeons, this adds another layer of responsibility. You can’t rely on a relative’s permission or assume someone wants surgery “because it will help them.” The law requires that any best-interests decision considers the person’s previous wishes, feelings, and values as far as possible.
For patients and families, it’s equally important to understand that no one can force you into surgery without consent — unless there’s a genuine emergency and you’re unable to decide.
What Counts as a Material Risk in Cataract Surgery?
The Montgomery case changed how “risk” is defined in medical law. A risk is material if a reasonable person in the patient’s position would want to know about it, or if the doctor knows that particular patient would want to know.
In cataract surgery, the following are generally considered material risks:
- Infection inside the eye (endophthalmitis)
- Permanent vision loss
- Retinal detachment
- Posterior capsule rupture
- Need for further surgery or laser treatment (YAG capsulotomy)
- Persistent blurred or double vision
- Glare or haloes
- Unsatisfactory refractive result requiring glasses
Even if these complications are rare, they are serious enough that most patients would want to be informed. Surgeons should also discuss non-surgical risks such as delayed healing or sensitivity to bright light.
The conversation should be individualised — not every patient needs an exhaustive list, but every patient deserves a clear, honest explanation relevant to them.
The Documentation: Why It’s More Than Paperwork
Every NHS and private clinic has a consent form, but the form itself is not consent. It’s simply the written record of a conversation that should already have taken place. The GMC and medical defence organisations often remind doctors that a signed form won’t protect them if the discussion was poor or rushed.
Good documentation should record what was explained, what the patient asked, and how the surgeon checked understanding. Some ophthalmologists now include notes about the patient’s priorities — for instance, “patient values driving vision” or “wants to avoid glasses if possible.” That context helps show that the decision was genuinely personalised.
If you’re a patient, you have the right to take the information home, discuss it with family, and come back with questions. Consent is not a one-time event; you can change your mind at any point before the operation.
Shared Decision-Making in Practice
Shared decision-making means that you and your surgeon decide together what’s best, rather than the doctor deciding for you. In cataract surgery, this might involve comparing different intraocular lenses (IOLs), such as monofocal, multifocal, or toric lenses, depending on your visual goals and budget.
The surgeon’s role is to provide evidence-based information and clinical recommendations, while your role is to express your values and preferences. For example, if you do a lot of night driving, you might prefer a monofocal lens to avoid glare. If you’re keen to reduce dependence on glasses, a multifocal or EDOF lens might be discussed.
This kind of dialogue takes time, but it’s the cornerstone of modern consent. It leads to better satisfaction, fewer complaints, and a stronger trust between patient and surgeon.
The GMC stresses that even when patients defer to their doctor’s recommendation, the decision must still be based on a meaningful exchange of information — not just, “Do whatever you think best, doctor.”
When Consent Fails: Legal and Professional Consequences
Failure to obtain valid consent can have serious implications. If a patient suffers harm and it’s found that they weren’t properly informed, the surgeon could face legal action for negligence.
In civil law, compensation claims often revolve around whether a patient would have made a different decision if properly informed. Regulatory bodies such as the GMC can also take disciplinary action if a doctor consistently fails to follow consent standards.
For example, if a cataract surgeon routinely delegates risk discussions to nurses without personal involvement, or omits key risks in documentation, that could be viewed as misconduct. The courts and the GMC now expect a very high standard of patient-specific discussion, not generalised information.
Special Scenarios: Private vs NHS Settings
Consent principles apply equally in both NHS and private cataract surgery, but the context can differ. In private practice, patients are often choosing between premium lens options and paying directly, which means financial consent overlaps with medical consent.
Surgeons must make it crystal clear what is included in the package — for instance, whether postoperative care or enhancement procedures are covered. Patients must also be told if a particular lens choice involves higher risk of glare, halos, or adaptation difficulties.
In the NHS, lens choices are usually standard monofocal options, so the focus is more on clinical suitability and timing rather than product selection. But the ethical and legal framework — respect for autonomy and full disclosure — remains identical.
The Future of Consent in Ophthalmology
Digital consent tools are becoming increasingly common in the NHS and private eye hospitals. These platforms allow patients to watch information videos, read about risks, and electronically sign consent forms. They can improve accessibility and consistency — especially for patients with language barriers or those needing extra time.
However, digital systems are not a substitute for human conversation. The best approach combines both: online resources to help patients understand, and a personalised discussion with their surgeon to clarify doubts.
As medicine evolves, one thing remains constant: the patient’s right to make an informed choice. Cataract surgery may be quick and low-risk, but the ethical standards around consent are as strict as ever.
Frequently Asked Questions
1. Do I have to sign a consent form before cataract surgery?
Yes, you do — but signing the form is only one part of the process, not the main event. The true consent process is the series of conversations you have with your surgeon beforehand, where you discuss your vision goals, potential risks, and any alternatives. The signed form is just written evidence that those discussions took place. It should reflect an informed decision, not replace it. If you ever feel like you’ve been handed a form to sign without a proper talk first, it’s completely appropriate to ask for a more detailed explanation.
2. What happens if I change my mind after signing the consent form?
You have the legal right to change your mind at any point before the surgery begins, even if you’ve already signed the consent form. Consent in the UK is a continuous process, not a fixed contract. If you later decide you’re not ready or want to explore other options, your surgical team must respect that choice. No doctor can proceed with cataract surgery without your ongoing and voluntary agreement. It’s always better to delay and feel confident than to go ahead when uncertain.
3. Can someone else give consent for me if I can’t decide?
If you’re unable to make or communicate a decision due to conditions such as dementia, confusion, or a temporary loss of consciousness, someone legally authorised — usually a person with a lasting power of attorney (LPA) for health and welfare — can consent on your behalf. If no LPA exists, doctors must act in your best interests, following the Mental Capacity Act 2005. This means they’ll consider your previous wishes, beliefs, and values, as well as consulting close family members or carers. No one can override your decision while you still have capacity.
4. What if the surgeon doesn’t mention a risk that later happens?
If a complication occurs that wasn’t explained beforehand, the key question is whether that risk was something a reasonable person in your position would have wanted to know about. Under the Montgomery ruling, doctors must disclose all material risks — meaning those that could influence a patient’s decision. If a risk was serious and relevant but not mentioned, it may be grounds for a complaint or legal claim. This is why open, honest discussions before surgery are so crucial for both sides.
5. How do I know the surgeon has properly explained everything?
You’ll know the consent discussion was thorough when you feel comfortable asking questions, understand the benefits and drawbacks of surgery, and can clearly explain back what you’ve been told. A good surgeon won’t rush or use overly technical language. They’ll also make sure you understand the likelihood of complications and what happens if you choose not to have surgery. If you leave the consultation feeling uncertain or confused, that’s a sign to ask for more time or information before deciding.
6. Is consent different in private cataract surgery?
The principles are exactly the same whether you’re treated privately or on the NHS. The key difference is that private patients often have more options, such as premium lenses or combined procedures, which can make the discussions longer and more detailed. Surgeons must still provide all the same information about risks, benefits, and costs, and you should have just as much opportunity to ask questions. Consent in private practice is both a medical and financial process, and full transparency is essential for both.
7. What if I feel pressured to go ahead with surgery?
You should never feel pressured, rushed, or coerced into having cataract surgery. True consent must be voluntary. If you’re not ready, you can postpone the operation until you’re confident in your decision. You also have the right to seek a second opinion from another surgeon if you want to confirm the advice you’ve been given. Ethical surgeons and clinics will always support that choice, as informed, willing patients are far more likely to achieve a successful outcome and feel satisfied afterwards.
8. Can I record the consent discussion?
Yes, you can, as long as you inform your surgeon before doing so. Many patients find it helpful to record the consultation or take notes, especially if they struggle to remember complex information. It’s perfectly reasonable to do this for personal use, to review the details later or share them with family members. Most doctors are used to this and will appreciate your effort to understand the process fully. The aim of consent is clarity — whatever helps achieve that is encouraged.
9. Does the surgeon have to tell me about very rare risks?
If a risk is rare but serious — for example, infection or permanent loss of vision — your surgeon must still mention it, even if the chance is tiny. The law focuses on the impact of the risk, not how often it happens. On the other hand, very minor or temporary side effects that wouldn’t normally influence your decision may not need detailed discussion. A good surgeon will balance this by explaining which risks are statistically low but still important to consider in your case.
10. How long is consent valid for?
Consent is valid for as long as the information, your condition, and the proposed procedure remain the same. If there’s a long delay between your consultation and the operation, or if something changes in your health or the planned technique, your surgeon should revisit the discussion. This is known as “reconfirming consent.” It ensures that your decision is still based on accurate, current information. Think of it as a respectful check-in rather than an administrative task — it’s there to protect you.
Final Thoughts
Cataract surgery has one of the highest success rates in modern medicine, but success isn’t just measured in clear vision — it’s also measured in how well patients are informed, respected, and involved in decisions about their care.
For surgeons, getting consent right isn’t about ticking legal boxes; it’s about practising medicine with integrity. For patients, understanding your rights helps you engage confidently in your care.
At London Cataract Centre, our team ensures every patient has the time, clarity, and reassurance they need before deciding on surgery. Informed consent isn’t just good ethics — it’s good medicine.
References
- General Medical Council (2020) Decision Making and Consent – Professional standards. London: GMC. Available at: https://www.gmc-uk.org/professional-standards/the-professional-standards/decision-making-and-consent (Accessed: 4 November 2025).
- Supreme Court of the United Kingdom (2015) Montgomery (Appellant) v Lanarkshire Health Board (Respondent) [2015] UKSC 11. Available at: https://www.supremecourt.uk/cases/uksc-2013-0136 (Accessed: 4 November 2025).
- General Medical Council (2020) Factsheet – Key legislation and case law relating to Decision Making and Consent. London: GMC. Available at: https://www.gmc-uk.org/-/media/documents/factsheet—key-legislation-and-case-law-relating-to-decision-making-and-consent-84176182.pdf (Accessed: 4 November 2025).
- Academic article: Purcell, G. (2023) ‘The conundrums of the reasonable patient standard in English medical law’, Journal of Medical Ethics, 49(3), pp. 175-181. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC9948388/ (Accessed: 4 November 2025).
- MDU Journal (2020) ‘Seven Principles of Consent: Latest GMC Guidance’, MDU Journal – Winter 2020. Available at: https://mdujournal.themdu.com/issue-archive/winter-2020/seven-principles-of-consent-latest-gmc-guidance/ (Accessed: 4 November 2025).