Types and Forms of Consent

Consent varies by decision, form, and the level of information provided. Recognising these distinctions helps ensure patient permission is proportionate to the intervention.^[3]

Types of consent

In day-to-day practice, teams often refer to:

• Implied consent - inferred from actions such as sitting in the test chair or placing the chin on the slit-lamp; suitable for routine, low-risk steps but with clear limits.^[1]
• Express consent - given explicitly, verbally or in writing, for specific interventions (e.g., agreeing to pupil dilation or contact lens fitting).^[2]
• Informed consent - only valid where the patient understands the nature, purpose, benefits, risks, and alternatives of the procedure.^[3]
• Valid consent - combines capacity, adequate information, and voluntariness; all three must be present.^[3]
• Specific consent - tied to a clearly defined decision (e.g., referral for cataract surgery) and does not automatically extend to other procedures.^[2]

Forms of consent

Documentation can reflect what best fits the situation:^[1]

• Verbal consent - common in optical practice, for example when agreeing to intraocular pressure measurement.^[4]
• Written consent - appropriate for higher-risk interventions (e.g., refractive surgery or invasive procedures) where a record is essential.^[2]
• Behavioural/implied consent - observed through cooperation with an examination step, such as following fixation targets during visual field testing.^[1]

Everyday examples in optical care

Applying proportionality keeps consent practical and robust. ^[1]

• A sight test typically relies on implied consent when the patient sits in the test chair.^[1]
• Pupil dilation calls for express and informed consent, as effects such as light sensitivity and blurred vision must be explained.^[2][3]
• A surgical referral requires specific and informed consent so the patient understands why referral is needed, what it involves, and any alternatives.^[2][3]

References (numbered in text) Why we include references

1. Principles of consent. General Optical Council Find (opens in a new tab)
2. Consent. The College of Optometrists Find (opens in a new tab)
3. Decision making and consent. General Medical Council Find (opens in a new tab)
4. Consent to treatment. NHS Find (opens in a new tab)