Age-related macular degeneration (AMD) is the leading cause of visual impairment in the UK. The condition is characterised by damage to the region of the retina (macula) responsible for detailed central vision, this leading to problems with tasks such as reading and face-recognition. The ability to accurately measure vision is central to the detection and management of AMD. The most common test (visual acuity) typically requires patients to identify black letters of varying size on a white background, with the smallest letter read representing the limit of vision. Conventional tests are however known to be variable, making it difficult to determine if a true change in vision has occurred.

Previous work has found the Moorfields Acuity Chart, which contains specially constructed letters composed of a black core and white border, to be more sensitive to early AMD compared to standard charts. Despite this advantage, it is unclear if there is an associated increase in measurement variability with the Moorfields Acuity Chart and if this changes with the severity of disease. In this study, the relationship between vision test sensitivity and measurement variability will be quantified with both conventional visual acuity tests and the new Moorfields Acuity Chart to identify the optimal vision test to detect and monitor AMD in the clinic.

Group 2 - Healthy control participants:

Inclusion criteria will include:

• Absence of ocular disease in either eye
• Male or female, aged 18 years or older
• The absence of significant media opacities
• Ability to understand nature/purpose of the study and to provide informed consent
• Ability to follow instructions and complete the study
• Ability to speak English

Exclusion criteria will include:

• Any systemic disease likely to affect visual performance
• Presence of any ocular disease
• Hearing impairment sufficient to interfere with hearing instructions
• Poor understanding of English language and/or alphabet
• Any condition which, in the investigator's opinion, would conflict or otherwise prevent the subject from complying with the required procedures, schedule, or other study conduct.

Participants with reduced vision attributable to AMD will be recruited and tested as part of this study.