The Patient Who Cannot Consent Clearly
An 80-year-old woman is brought to the eye clinic by her daughter with a dense, mature cataract in the left eye causing counting-fingers vision; the right eye is 6/12. She has mild cognitive impairment (MMSE 22) and lives with her daughter, who provides most of her care. She is able to hold a conversation but repeats questions and cannot explain the risks of surgery back to you. The daughter is adamant that her mother 'would want it done' and asks you to book the operation. The patient herself says she 'wants to see better' but becomes distressed when you discuss the possibility of complications. Surgery is elective and would require her to lie still and cooperate with a local anaesthetic block and draping.
1. How do you assess whether this patient can consent to cataract surgery?
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Consent requires capacity for this specific decision, assessed functionally rather than by diagnosis or MMSE score alone. I would assess whether she can:
- Understand the relevant information - that she has a cataract, that surgery is an option, and the alternatives (including doing nothing).
- Retain it long enough to decide.
- Weigh it - appreciate the likely benefit against the risks of surgery and of not operating.
- Communicate a choice.
Her mild cognitive impairment does not automatically mean she lacks capacity. But her inability to explain the risks back, her repetition, and her distress when complications are discussed suggest she may not currently meet the 'understand and weigh' limbs for this decision. I would assess in a quiet setting, over more than one conversation, using simple language and perhaps written or pictorial aids, and involve her daughter to support communication (not to substitute her own decision).
2. If she is judged to lack capacity for this decision, what is the correct process, and what is the daughter's role?
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If she lacks capacity for this specific decision, the decision must be made in her best interests, following the legal framework in force (in the UK, the Mental Capacity Act 2005):
- Presume capacity unless established otherwise; assess for the specific decision.
- Support her to participate as far as possible - her stated wish to 'see better' is relevant and should be weighed.
- Consider less restrictive options and whether the decision can be deferred.
- Consult people who know her well - her daughter - to establish her past and present wishes, feelings, beliefs and values. The daughter is a source of evidence about what her mother would want, not a person who can consent on her mother's behalf to elective treatment.
- Where there is no one with legal authority (e.g. a health and welfare attorney or deputy), consider whether an Independent Mental Capacity Advocate should be involved for a serious decision.
For an elective operation, the bar for proceeding in the patient's best interests is higher; if the benefit is uncertain or she would be distressed and uncooperative, it may be right to defer.
3. What practical factors would influence whether surgery is in her best interests, beyond the consent question?
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Best interests is broader than paperwork:
- Ability to cooperate: cataract surgery under local anaesthetic requires lying still, tolerating drapes, and cooperating with the block and the microscope. Her distress and cognitive impairment raise a real risk of an unsafe, aborted, or complicated procedure. Alternatives include general anaesthesia (with its own risks in an 80-year-old) or deferring.
- Likely benefit: the left eye is counting fingers and the right eye is 6/12 - she is not functionally blind, so the urgency is low and the operation can be planned carefully. Improving the worse eye may still meaningfully help her.
- Support and follow-up: her daughter's involvement in drops, appointments, and aftercare matters for a good outcome.
- Reversibility and alternatives: optimising the right eye, low-vision aids, and home environment changes may be reasonable interim options.
The judgement is that this is an elective operation where the process - assessing capacity properly, involving the family as evidence of wishes, planning anaesthesia to maximise cooperation, and documenting the best-interests decision - matters as much as the surgery itself.