Relationships Among Pupil Responses to Light, Circadian Rhythms, and Sleep

The investigators are studying relationships among eye pathology, pupil responses to light, sleep, circadian rhythms, and hormones in healthy individuals and those with various medical disorders or illnesses.

All participants will:

* Answer questionnaires about their health * Receive an eye exam, * For one week at home, participants will track their sleep and wake using actigraphy (wrist worn wearable) and an online sleep diary. * Complete a pupillometry session (measuring pupil size in response to different lighting) at MGH

Participants may also choose to participate in the following additional procedures in any order:

* Within one week of their pupillometry session, an at-home saliva collection under dim light. Saliva melatonin can be analyzed to determine Dim-Light-Melatonin-Onset (DLMO), a marker of circadian timing. * If participants participate in one night saliva collection, a second night of at-home saliva collection with a bright light exposure to calculate melatonin suppression in response to light.