Award Date


Degree Type


Degree Name

Doctor of Philosophy (PhD)



First Committee Member

Daniel Allen

Second Committee Member

Bradley Donohue

Third Committee Member

Rachael Robnett

Fourth Committee Member

Katherine Hertlein

Number of Pages



BackgroundInsomnia impacts 30% of people and is associated with increased risk for medical and psychiatric illness. However, pharmacological treatments for sleep yield mixed results and often result in undesirable side effects indicating a need for novel insomnia interventions. Sleep patterns also demonstrate high intra-individual variability which may be associated with greater daytime impairment, and sleep-wake cycles are strongly affected by the timing of exposure to blue-green wavelength light. Virtual darkness, a novel intervention, blocks blue wavelength light from reaching the eye to simulate actual darkness on retinal cells sensitive to light. Therefore, the purpose of the current study is to examine whether virtual darkness is a feasible intervention to improve insomnia symptoms and decrease sleep variability.

MethodsParticipants were young adults with moderate to severe insomnia and were randomized to one of three treatment conditions in a double-blind, placebo-controlled, crossover design. Participants wore clear glasses (placebo) or blue-light filtering glasses (virtual darkness) for three hours prior to bedtime and completed a sleep diary and mood questionnaire each morning. Participants texted a selfie to monitor compliance with wearing the study glasses each night and reported side effects weekly. Mixed-effects location-scale models (MELSM) were used to assess whether virtual darkness improved total sleep time (TST), sleep efficiency (SE), sleep onset latency (SOL), number of times waking after sleep onset (WASO), sleep quality, and mood, calmness, and energy upon waking

ResultsOn average, participants demonstrated 90% compliance with wearing the study glasses. The most common intervention related side effects were mild eye strain and head pressure while wearing the placebo and active treatment glasses. MELSM results indicated that participants’ SOL significantly improved with treatment such that participants fell asleep faster during the virtual darkness phase compared to placebo. Participants also had decreased WASO, better self-reported sleep quality, more positive mood upon waking, and greater calmness upon waking during the virtual darkness phase. Intra-individual variability of SOL also improved with SOL becoming 47% more consistent during the virtual darkness phase compared to placebo. Virtual darkness did not significantly impact TST, SE, or energy upon waking.

ConclusionsPreliminary results suggest that virtual darkness may represent a promising low-cost intervention for insomnia symptoms. Treatment with virtual darkness resulted in clinically meaningful improvements in sleep outcomes.

Controlled Subject

Light and darkness; Sleep; Sleep disorders; Insomnia


Clinical Psychology

File Format


File Size

1259 KB

Degree Grantor

University of Nevada, Las Vegas




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