The Mental Capacity Act 2005

The MCA provides the legal framework for decision-making when capacity is in doubt.^[1][2] Capacity is decision- and time-specific: an adult may have capacity to choose frames yet lack capacity to consent to complex treatment.^[2]

Optical professionals support decision-making before concluding incapacity, record assessments clearly, and apply the best interests process when capacity is absent.^[4][3]

The MCA's five principles applied to clinics

• Presume capacity unless proven otherwise.^[1][2]
• Support decision-making: adjust communication (plain English, large print, visual aids), allow extra time, involve a supporter chosen by the person.^[3][2]
• Right to make unwise decisions: a risky choice does not equal incapacity; look at understanding and rationale.^[1][2]
• Best interests: if capacity is lacking, choose options that reflect the person's values and will, considering benefits/risks and least restrictive alternatives.^[1][2]
• Least restrictive option: achieve the goal with minimal infringement of rights and freedoms.^[1][2]

Functional test and recording

Capacity requires the ability to understand, retain, use or weigh, and communicate relevant information.^[1][2]

In optics, relevance includes the purpose and effects of dilation, risks of not treating glaucoma, and consequences of acquiring costly spectacles.^[4][3]

Document questions asked, adjustments provided, the person's responses, and the conclusion. Where capacity fluctuates, revisit later if safe; for urgent risk (e.g., suspected angle closure), act now under best interests and record why delay was unsafe.^[3][1][2]

Best interests and representation

When capacity is absent, consult those who know the person well and consider any advance statements. For significant decisions without family/friends, involve an Independent Mental Capacity Advocate (IMCA) as required.^[2][5]

Best-interest rationale should show how the decision reflects the individual's values, not professional convenience. Recording this process protects the person and provides clear reasoning for partners reviewing the case.^[2][3]

References (numbered in text) Why we include references

1. Mental Capacity Act 2005 — UK Public General Acts (legislation.gov.uk), 2005 Find (opens in a new tab)
2. Mental Capacity Act Code of Practice — Office of the Public Guardian (GOV.UK), Published 22 July 2013 Find (opens in a new tab)
3. Decision making and consent — General Medical Council, came into effect 9 November 2020 Find (opens in a new tab)
4. Consent — College of Optometrists (College of Optometrists clinical guidance) Find (opens in a new tab)
5. Independent mental capacity advocates — Office of the Public Guardian and Department of Health and Social Care (GOV.UK), Published 27 November 2007; Last updated 26 June 2025 Find (opens in a new tab)