The goal of this study is to understand how caffeine and alcohol affect the ocular and physiological systems, especially how the pupil (the aperture in the colored part of the eye) responds to light. It will also test whether these changes can be used to detect recent caffeine or alcohol intake using a portable eye device.
The main questions it aims to answer are:
1. How does caffeine change pupil responses, eye movements, and other ocular and physiological measurements? 2. How does alcohol change these same ocular and physiological responses? 3. Are the effects of caffeine and alcohol different from each other? 4. Can these changes be used to accurately identify whether someone has consumed caffeine or alcohol?
Researchers will compare caffeine, alcohol, and a placebo (a look-alike drink with no active substance) to see how each affects the ocular and physiological outcomes.
Participants will:
1. Attend three separate sessions where they will consume caffeine, alcohol, or a placebo (in random order) 2. Undergo pupillary response evaluation using a handheld device that measures responses to different colored light stimuli 3. Have their eye movements analyzed 4. Have retinal and choroidal thickness, blood perfusion, and ocular oxygen levels measured 5. Have basic body measurements recorded (such as pulse rate and blood pressure) 6. Complete tests at multiple time points over 2 hours after consumption
The results of this study may help develop a quick and non-invasive way to detect recent caffeine or alcohol use for clinical and safety purposes.
Age: 30 to 50 years of age
Visual Acuity: Best Corrected Visual Acuity (BCVA) of 0.20 LogMAR or better in both eyes
Ability to provide informed consent: Participants must be able to understand and sign the informed consent form
Ability to consume both caffeine and alcohol: Participants must be willing and able to consume caffeine and alcohol as part of the study
Diagnosed ocular conditions: Participants with ocular or ocular movement diseases such as glaucoma, age-related macular degeneration, diabetic retinopathy, amblyopia, severe ptosis, or conditions relating to pupils: anisocoria, irregular pupil, Adie tonic, Horner's syndrome, Argyll Robertson pupil, etc. These exclude cataracts, refractive errors, and any ocular condition not affecting vision or ocular movement or obstructing the pupil.
Diagnosed and unresolved neurological conditions:Stroke, unresolved traumatic brain injury, space-occupying lesions in the brain, neuropathies, demyelinating conditions, nerve palsies, etc.
Diagnosed systemic conditions that may restrict the participant from drinking caffeine or alcohol: Hypertension, cardiovascular disease, liver disease, kidney disease, etc.
Medications: Participants taking any medications that may interact with caffeine or alcohol, affect alertness, or cause drowsiness
National University of Singapore
Lead sponsor
Home Team Science & Technology Agency (HTX)
Collaborator