The Three Elements of Valid Consent

Valid consent exists only when three elements are present: competence or capacity, sufficient information, and voluntariness. If any element is missing, consent is not legally or ethically valid-even if the patient appears to agree. Meeting GOC Standard 3 depends on assessing each element in practice. ^[1]

Competence and capacity

Adults are assessed for capacity under the Mental Capacity Act 2005.^[2]

They should be able to understand, retain, weigh up, and communicate relevant information. Capacity may fluctuate-such as in dementia-so decisions are assessed at the time of care. ^[2]

For children, the Children Act 1989 and Gillick competence guide decision-making. A child under 16 can consent independently if they demonstrate sufficient maturity and understanding of the proposed care (e.g., a contact lens fitting). Where competence is uncertain, parental involvement is needed, while still considering the child's views. ^[7][5]

Information

Consent is not valid unless information is provided in a way the patient can understand. Key elements include: ^[4]

• The purpose and nature of the proposed procedure or treatment.
• Potential risks, side effects, and expected benefits.
• Reasonable alternatives-including doing nothing-and the likely consequences of refusal.

In practice, this could mean explaining that dilation drops will blur vision and cause light sensitivity, or that declining referral for raised intraocular pressure carries a risk of glaucoma progression. Tailoring information to health literacy, language, and sensory needs helps ensure accessibility. ^[6]

Voluntariness

Consent must be free from undue pressure or coercion. Influence may come from relatives, carers, or practitioner authority, but the decision should ultimately be the patient's. For example, a relative insisting on spectacle choices against the patient's wishes, or a patient feeling obliged to accept optional procedures as if they were mandatory. ^[1][4]

Creating space for private discussion where needed, checking that the decision is genuinely the patient's, and documenting any concerns about external influence all help confirm voluntariness. Only when competence (or capacity), information, and voluntariness align can consent be considered valid. ^[4][1]

References (numbered in text) Why we include references

1. Consent — General Optical Council Find (opens in a new tab)
2. Mental Capacity Act 2005 — UK Parliament (legislation.gov.uk) Find (opens in a new tab)
3. Mental Capacity Act Code of Practice — Office of the Public Guardian / GOV.UK Find (opens in a new tab)
4. Decision making and consent — General Medical Council Find (opens in a new tab)
5. Making decisions (0–18 years) — General Medical Council Find (opens in a new tab)
6. Accessible Information Standard – implementation guidance — NHS England Find (opens in a new tab)
7. Children Act 1989 — UK Parliament (legislation.gov.uk) Find (opens in a new tab)