Ophthalmology is among the most technology driven of all medical specialties, with advanced medical imaging devices - and specialised computer software - increasingly adopted for routine clinical use. While many such devices are capable of completing specific tasks, lack of "usability" prevents their widespread adoption (i.e., such devices are not easy to learn and remember, or are not efficient or subjectively pleasing to use). Moreover, devices that are difficult to use expose patients to clinical risk as a result of human error during usage.

With the introduction of a new medical technology, it is essential, therefore, to have a deep understanding of patients, what they need, what they value, their abilities, and also their limitations.

Human factor and usability testing, also known as "human factor engineering", deals with the formal study of people's interaction with their environment (in this case, the binocular optical coherence tomography (OCT) device). Structured, patient-centred, usability testing is essential to the design, clinical validation, regulatory approval, and widespread implementation, of all new medical devices. This is particularly the case for a putative binocular OCT system - a device intended for automated use in visually impaired, often elderly, populations. Although the binocular OCT is already at an advanced stage of hardware development, the EASE study will facilitate an iterative process of operating software and workflow modifications to optimize the device for use in these populations.

Inclusion criteria for participants with chronic eye disease will include:

• Presence of retinal disease, glaucoma or strabismus
• Male or female, aged 18 years or older
• Ability to understand nature/purpose of the study and to provide informed consent
• Ability to undergo binocular OCT imaging
• Ability to follow instructions and complete the study
• Ability to speak English

Exclusion criteria for participants with chronic eye disease will include:

• Optical media opacity sufficient to preclude adequate ocular imaging with OCT
• Hearing impairment sufficient to interfere with hearing instructions
• 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.

Inclusion criteria for healthy subjects will include:

• No self-reported ocular history (although wearing corrective prescription glasses is permitted)
• Male or female, aged 18 years or older
• Ability to understand nature/purpose of the study and to provide informed consent
• Ability to undergo binocular OCT imaging
• Ability to follow instructions and complete the study
• Ability to speak English

Exclusion criteria for healthy subjects will include:

• Presence of ocular pathology
• Hearing impairment sufficient to interfere with hearing instructions
• 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 chronic eye disease (retinal disease, glaucoma, and strabismus) will be recruited from appropriate eye clinics at Moorfields Eye Hospital and from a patient advisory group established for this purpose.