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Blue blocking glasses worn at night in first year higher education students with sleep complaints: a feasibility study
© The Author(s). 2018
- Received: 26 March 2018
- Accepted: 22 October 2018
- Published: 1 November 2018
Late adolescence and early adulthood is a period of highest incidence for onset of mental health problems. Transition to college environment has been associated with many risk factors such as the initial disruption—and subsequent irregularity—of the student’s sleep and activity schedule. We tested the feasibility of using blue blocking glasses (BBG) at night in first year higher education students with sleep complaints, to obtain preliminary evidence for the impact of BBG on sleep, activity, and mood.
Participants were 13 first year undergraduates (from 10 different academic courses) living on campus for the first time with sleep complaints/disorders confirmed at screening via the Duke Structured Interview Schedule for Sleep Disorders. We used a 2-week, balanced crossover design (BBG vs placebo glasses; participants were unaware which was the active intervention) with computer-generated random allocation. Exploratory analyses provided descriptive and frequency summaries to evaluate feasibility of the intervention.
Preliminary evidence supports the feasibility and acceptability of the trial; almost all screened participants consented and completed the protocol with high adherence; missing data were negligible. Additionally, the effectiveness of BBGs to enhance sleep, mood, and activity levels in young adults was supported.
The results of this feasibility trial suggest that BBG have potential as an inexpensive and feasible intervention for reducing sleep and circadian dysregulation in young adult students. A larger trial, following this successfully implemented protocol, is necessary to fully test the efficacy of BBG.
- Blue blocking light
Late adolescence and early adulthood, a time associated with newfound independence and excitement for the future, is also the period of highest incidence for onset of mental health problems . Research on the prevalence of mental health disorders on college campuses suggest that nearly half of students are affected [2, 3].The college environment is associated with many risk factors for vulnerable individuals, including easy access to alcohol and drugs, and reduced contact with family and existing support networks. Among the most powerful risk factors may be the initial disruption—and subsequent irregularity—of the student’s sleep and activity schedule . In secondary school, most adolescents live structured lives, bound by obligations of school, extracurricular activities, family, parental control, and social life; but for many in college, classes are infrequent, and at least early on, there are fewer other obligations to meet, which can lead to irregular sleep and activity schedules [5, 6]. These risk factors may be particularly likely to increase risk for mood pathology; research has shown that depression is associated with insomnia and social isolation [7, 8]; and sleep disturbances and irregular social behavior are associated with mania and bipolar disorder [6, 9]. Research suggests that a young adult, deprived of only one night’s sleep, will experience greater levels of anger, anxiety, and stress than if s/he did sleep [7, 10]. Additionally, even relatively minor sleep disruptions due to social events or schoolwork can negatively impact daytime functioning and temporarily lower mood and decrease academic performance .
Disturbances of sleep and daily activity interfere with the circadian rhythm—the body’s clock , which is responsible for maintaining myriad biological processes, including sleep, metabolism, and energy . The impact of dysregulated circadian rhythm is evident in other systems; for example, poor sleep is associated with weight gain . Importantly, disruptions of the circadian rhythm and the resulting impact on mental and physical health are not due only to schedule disruptions; exposure to blue light—the type emitted from the sky (and from our omnipresent electronic devices)—is also a factor [12, 14]. Specifically, specialized retinal ganglion cells containing melanopsin (OPN4) track levels of blue and blue-green light (peak sensitivity ~ 470 nm) and signal the master clock in the brain (the suprachiasmatic nucleus of the hypothalamus ), to regulate other body processes to achieve the appropriate state of alertness (or sleepiness) based on environmental cues [12, 16]. In addition to time spent in front of the computer for academic reasons, young people tend to spend a significant amount of time in the evening engaging with technology—TV, video games, text messaging, etc. On average, they engage in more than four such activities after 9 pm . This affects sleep significantly: Most adolescents and young adults get less than 8 h of sleep during the week—in many cases directly attributable to electronic device use , the consequences of which include depression, obesity, and poor academic performance .
These negative outcomes can derail an individual’s future . Preventing depression, obesity, and poor academic performance during this period would be ideal, and evidence suggests that targeting students’ sleep problems can have broad, positive effects . A new intervention, “virtual darkness” [14, 21], generated by wearing blue blocking glasses (BBG) may address this need. BBG work by “tricking” the body’s clock into believing that it is nighttime regardless of the blue light (whether from devices or the sky) in the environment . Previous research has demonstrated that BBG can have a potent mood-stabilizing effect on inpatient adults with bipolar disorder  and can regulate sleep and improve mood in both healthy people  and postpartum women . Importantly, BBG are a safe and well-tolerated intervention, positioning “virtual darkness” as a candidate preventive intervention that deserves further evaluation, particularly in groups in which sleep disturbance is prominent, like college students.
Our primary aims were to test the feasibility and acceptability of a balanced crossover design and to evaluate the effects of BBG in first year higher education students with sleep complaints. Changing sleep behaviors is often difficult , and given the unique living arrangements and social pressures on campus (i.e., students live together which creates an environment that might be incompatible with wearing glasses and/or with modifying one’s sleep, even if the BBG increased sleep drive, as expected), we determined that it was necessary to first test whether participants would follow the study protocol before launching a larger efficacy trial. Based on previous research [21, 22], we hypothesized that we would be able to successfully recruit our target sample (> 80% of N = 15) and that at least 70% of consented participants would complete the trial and demonstrate adequate adherence to the BBG protocol. Further, when BBG were worn at night for 3 h before target bedtime, we expected that preliminary evidence would show an effect in the expected direction of BBG improving sleep, activity, and mood, compared to a non-BBG intervention.
This study used a 2-week, balanced crossover design with computer-generated random allocation. The Faculty of Health and Medicine Research Ethics Committee (FHMREC), Lancaster University, approved the research protocol. Participants provided written informed consent. After protocol completion, participants were debriefed and received an Amazon voucher worth £75.
We recruited 13 Lancaster undergraduates (from 10 different academic courses) from October 2015 to April 2016 via advertisements around campus. Sample size determination was based on pragmatic factors such as limited resources from pilot grant that payed for up to 15 participants. Inclusion criteria were first year undergraduates students living on campus for first time with sleep complaints/disorders confirmed at screening via the Duke Structured Interview Schedule for Sleep Disorders (DSISD; ). We excluded participants if they were unable or unwilling to comply with protocol; reported having severe retinal or corneal damage on both eyes; reported daily use of non-steroidal anti-inflammatory drugs, beta blockers, calcium-antagonist, or central stimulants like methylphenidate or venlafaxine; reported traveling outside the UK time zone during the past 2 months; reported changes in hormonal contraceptives during the past 2 months; or had brain dysfunction as observed during the screening interview.
Participant characteristics (e.g., demographics) and questionnaires were collected online via Qualtrics software (2005), Version 3.5.0, Copyright © .
Feasibility outcomes, such as protocol acceptance, were measured through recording of daily activities via Qualtrics (e.g., sleep diary completion and BBG wearing times) and corroborated by objective measurement of wear times of the actigraph. We collected data about recruitment timeline, and attrition and retention through database records. At the end of the study, the PI had a brief debriefing interview with participants, to ask about the experience of wearing BBG and whether participants accessed information on BBG from external sources during trial (which could create an expectancy effect confounding self-report of some measures of interest in future studies), and to get any suggestions about improving tolerability.
The 7 Up-7 Down  is a 14-item self-report scale carved from the 73-item General Behavior Inventory . It shows good internal consistency, high correlations with the full length scales, and good discriminative validity separating cases with mood disorders from other clinical complaints.
The Positive Affect–Negative Affect Schedule (PANAS)  is one of the most widely used rating scales to measure positive and negative emotions. It has 10 items of each valence rated on a Likert-type scale.
The PI screened and consented all participants. At screening, participants were evaluated with the Duke Structured Interview Schedule for Sleep Disorders (DSISD; ). Baseline measures were repeated at days 3, 7, 10, and 14. Active (sleep log diary) and passive (Actigraphy, Actiwatch 2, Philips Respironics) activity and sleep data were collected daily, and sleep time and architecture based on peripheral arterial tone plus pulse oximetry (WatchPAT200, Itamar Medical  were collected at days 7 and 14.
Baseline data (days 1–3) was collected, and glasses and procedure were introduced to participants by PI. On day 4, participants previously matched by gender and morningness/evening preference at screening were randomly allocated (by computer) to wear either amber (active BBG; Uvex S1933X with required wave-length-blocking properties) or blue glasses (non-BBG; Uvex S1932X). Participants were told by PI that we were testing two pairs of glasses, each of which filtered different wavelengths of light, to reduce the likelihood of participant expectations about the effects of the BBG versus the blue glasses). Participants were instructed to put on the glasses at least 3 h before their target time to fall asleep until sleep onset each night (e.g., a participant with the goal of falling asleep at 1 am on day 4 would use the lenses after 10 pm with instructions to avoid taking them off until bedroom lights were off). A washout period occurred during days 8, 9, and 10 (no glasses). On day 11, participants crossed over to the other color of glasses. We asked participants to maintain their regular sleep-wake schedule during the 2-week period.
Exploratory analyses provided descriptive and frequency summaries to evaluate feasibility of the intervention. Non-parametric tests (independent-samples Mann-Whitney U tests) compared medians between groups at night 7 and 14. Functional linear modeling of actigraphy data  investigated patterns of activity during intervention. Hierarchical linear modeling inspected preliminary evidence of impact of the intervention on self-report mood measures. Analyses were conducted in SPSS version 23 using the Actigraphy package  in R .
We report data for 12 participants (67% females; age mean 18.5, SD = .52; 5 White British, 4 Arabic, 2 Hispanic, and 1 Indian) who completed the 2-week protocol. One participant was unable to participate due to flooding on campus during scheduled data collection, and one participant was rejected for having traveled outside the UK time zone during the past 2 months.
Sleep disorder diagnoses based on Duke structured interview schedule for sleep disorders by participant (N = 12)
Sleep Disorder Diagnoses and ID
Primary insomnia, current
Circadian rhythm disorders
Dyssomnia (Restless legs syndrome, poss.)
Inadequate sleep hygiene
Insomnia related with MH (depr, past)
Breathing related sleep disorder, poss.
Insomnia related with MH (anx, past)
Parasomnia nos (Legs cramps, current)
Minimal criteria for insomnia
Parasomnia nos (Sleep paralysis, past)
Insomnia related with MH (past¤t)
Primary Insomnia, past
All participants who were screened and eligible for the trial agreed to take part in the study. Only one participant refused to participate before screening because of level of commitment needed to complete daily assessments. We had a retention rate over the 2-week protocol of 92%; all participants completed the trial. We did not make any adjustments to the eligibility criteria or study design/expectations once recruitment began.
Additionally, adherence to the study requirements was high. The median number of days wearing glasses was 8 for BBG (range 5 to 8, expected number of days was 8), and 7.5 for non-BBG (range 4 to 9). The median number of minutes wearing BBG glasses per day was ~ 196 min (range 140 to 228, expected minutes 180), and ~ 205 min for non-BBG (range 138 to 212). No adverse events or unintended effects were reported.
All 12 participants wore the actigraph watch according to protocol instructions, and completed all daily assessments via Qualtrics. The level of missing data at item level was negligible. Seventy percent (n = 9) completed both peripheral arterial tone and pulse oximetry assessments at night 7 and 14. None of the participants reported having accessed information about BBG from external sources such as internet during study. These findings support the feasibility and acceptability of BBG as a sleep intervention in university students.
Preliminary sleep, activity, and mood outcomes data
In terms of chronotype (morningness or eveningness preferences), the sample mean score was 14.58, SD = 3.48, range 9 to 20 from possible range of 0 to 24, where 0 means morningness preference.
Peripheral arterial tone plus pulse oximetry (WP-200) results at night 7 and 14 between groups
This study needs replication given the small sample size, and potential impact of design characteristics, in particular length of wash-out period on carry-over effects of BBG. Notably, all findings observed ran in the expected direction, supporting the potential use of BBG to target difficulties associated with circadian dysregulation, such as sleep or mood difficulties. However, given the small sample size, our analyses were not adequately powered and should be considered preliminary, pending replication in a larger, adequately powered efficacy study.
Wearing BBG at night shows promise as an inexpensive and feasible intervention for reducing problems associated with circadian dysregulation for young adults as well as adults. Larger studies with non-clinical and young clinical samples (inpatients and outpatients) should unpack the effects on cognitive functioning as well as mood and activity, as well as inform the development of more refined protocols for timing and otherwise improving sleep hygiene and implementation.
We thank the students who participate in our study and Lancaster University for support via Early Career Small Grants, Lancaster University—HRA7893.
This work was supported by the Early Career Small Grants, Lancaster University—HRA7893.
Availability of data and materials
The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.
GPA was the PI of the study and was in charge of conception of the manuscript, writing and data analysis. AVM contributed with conception of the paper, writing and draft readings. BD contributed with conception of the paper and draft reading. SJ supervised project and contributed with conception of paper and draft reading. EAY contributed with conception of project, paper, supervised data analyses, writing and draft reading. FL supervised full project, contributed with conception of paper, writing and draft reading. All authors read and approved the final manuscript.
Ethics approval and consent to participate
The Faculty of Health and Medicine Research Ethics Committee (FHMREC), Lancaster University, approved the research protocol (UREC Reference: S2014/106). Consent to participate was obtained from participants.
Consent for publication
Drs. GPA, AVM, SJ and FL have no conflicts of interest to disclose. EAY has consulted with Joe Startup Technologies, Janssen, Lundbeck, Otsuka, Western Psychological Services, and Pearson. BD has a licensing agreement with Lundbeck for the use of a psychosocial treatment manual for depression.
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