Sleep Quality
Conditions
Brief summary
The aim of this study is to determine the relative effectiveness of monocular and binocular light exposures, with and without selective blue-blocking filtering, on nocturnal melatonin suppression, subjective sleepiness, and visual performance of night shift workers.
Detailed description
Over the course of six, 5-hour study nights, 30 participants will be randomized to 6 study conditions, 1) binocular dim-light control unfiltered, (2) monocular dim-light control (one eye occluded), (3) unfiltered binocular, (4) unfiltered monocular (non-dominant eye occluded), (5) filtered binocular (both eyes filtered), (6) filtered monocular (non-dominant eye filtered, the other non-filtered). Saliva samples will be collected every 30 minutes for melatonin levels. Participants will also be asked to provide subjective sleepiness and visual performance will be assessed. Study nights will be separated by one week and each participant will be randomized to one of the six study conditions each night. All participants will see all conditions.
Interventions
DEVICEFiltered Eyewear
Filtered binocular viewing condition will be produced by eyeglasses frames with orange-tinted blue-blocking filter, eliminating all optical radiation for wavelengths shorter than 540 nm. For the filtered monocular condition, only the lens on the eyeglasses frame on the non-dominant eye will be tinted with the blue-blocking filter.
DEVICEUnfiltered Eyewear
For the unfiltered binocular, the subjects will wear transparent eyeglasses frames with no optical power. Unfiltered monocular vision will be produced by an opaque eyepatch occluding the non-dominant eye.
OTHERNo Filters
Dim lights with no filters.
Sponsors
Icahn School of Medicine at Mount Sinai
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
TREATMENT
Masking
SINGLE (Subject)
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
* Healthy
Exclusion criteria
* Bipolar disorder * Seasonal depression * Diabetes * High blood pressure * History of cancer * Obstructing cataracts * Macular degeneration * Diabetic retinopathy * Glaucoma * Use of melatonin supplements * Use of beta blockers * Use of sleep medications * Use of antidepressant medication
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Melatonin Levels AUC | Each night for 6 study nights | Melatonin levels to assess Melatonin Suppression. Saliva samples will be collected every 30 minutes for melatonin levels. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Karolinska Sleepiness scale to measure Subjective Sleepiness | Each night for 6 study nights | Subjective sleepiness will be measured using the Karolinska Sleepiness scale. This 9-point scale scores range from 1-9, where 1 = very alert, 3 = alert, 5 = neither alert nor sleepy, 7 = sleepy, but no difficulty remaining awake, and 9 = very sleepy, fighting sleep, an effort to remain awake. Full scale from 1-9. A higher number indicates greater sleepiness. |
| Numerical Verification Task (NVT) | Each night for 6 study nights | The NVT requires participants to compare 2 lists of 20 pairs of 5-digit numerals at 2 contrasts (0.2 and 0.8), and the response time required to complete the task is recorded as the performance measure. A faster response time indicates better visual performance. |
Countries
United States
Outcome results
None listed