Blocking Nocturnal Blue Light to Treat Insomnia: A Pilot Randomized Controlled Trial
Phase: NA
Conditions: Insomnia, Sleep
Sponsor: Columbia University

Official title:  
Blocking nocturnal blue light to treat insomnia: A pilot randomized 
controlled trial 
 
NCT #:  
NCT0268800 
 
Date of Document: 
July 26, 2018 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Study Design:  

The current proposal is for a randomized, placebo-controlled, crossover trial to test the effects of 
blocking nocturnal blue light exposure on sleep, sleep habits, and melatonin secretion in 
individuals with insomnia. This will be a combined ambulatory and laboratory investigation. The 
intervention will consist of wearing BB lenses which block 97% of blue light (Uvex amber lenses, 
Bandit wraparound glasses, Honeywell Safety, Smithfield, RI) or non-BB placebo lenses (Uvex 
clear lenses, Bandit wraparound glasses, Honeywell Safety, Smithfield, RI) for the 2 h preceding 
bedtime each night for 1 wk (Fig. 2). Intervention phases will be separated by a 4-wk washout 
period, to reduce carry-
over effects and study 
premenopausal 
women at the same 
menstrual cycle phase. 
This will be followed by 
crossover 
to 
the 
alternate 
intervention 
phase. 
Each 
1-wk 
intervention phase will 
conclude with an in-
patient laboratory visit to characterize the effects of the intervention on sleep and circadian 
physiology (Fig. 3). During the ambulatory portion, participants will be free-living and will expose 
themselves to their habitual light levels and choose their sleep timing. During the laboratory 
portion, an 8-h sleep episode will be scheduled based on participant’s habitual sleep times during 
the week preceding entry. For standardization, and to demonstrate the beneficial effects of the 
BB lenses for preserving nocturnal melatonin secretion, participants will be uniformly exposed to 
an LED light source for 2 h preceding bedtime during the laboratory portion (Fig. 3).  
Potential participants who reply to posted advertisements will be told about the study. They 
will then be scheduled to meet with research staff to sign consent forms and determine eligibility. 
Inclusion criteria will include age 18-65 y, and a report of insomnia for ≥ 1 month. To determine 
insomnia, participants will have scores indicative of the case definition of insomnia based on the 
Insomnia Symptoms Questionnaire. This validated questionnaire assesses the presence, 
frequency, and duration of symptoms, as well as daytime consequences. Symptoms assessed 
include difficulty initiating sleep, difficulty maintaining sleep, and experiencing sleep that is 
unrefreshing. Participants with a diagnosis of obstructive sleep apnea of at least moderate 
severity (apnea-hypopnea index ≥15 events/h), a STOP-BANG score > 5 indicative of a high risk 
of sleep apnea, or other sleep disorders such as periodic limb movement disorder or narcolepsy 
will be excluded. History of deep vein thrombosis will be exclusionary. Night or rotating shift 
workers, those who have traveled across time zones in the 2 wk preceding procedures, will be 
excluded, since these can affect circadian physiology. Participants will be free of any psychiatric 
or neurological disorders, as these can affect sleep/circadian rhythms. Participants will be 
excluded if they are smokers or taking beta-blockers (26), since these decrease melatonin 
release, or if they consume excessive caffeine (>500 mg/d). Hypnotics/sedatives for sleep can 
have been used, but participants will refrain from use for 2 wk preceding the start and throughout 
   1 wk AW; SSQ
   1 wk AW; SSQ
   1 wk AW; SSQ
   1 wk AW; SSQ
Enrollment
and 
Randomization
Blue-blockers,
2 h preceding 
bedtime for 1  wk
lab visit
#1
4-wk 
washout 
Figure 2. The randomized, placebo-controlled, crossover design. AW: actiwatch; SSQ:
subjective sleep quality.
Placebo lenses,
2 h preceding 
bedtime for 1  wk
lab visit
#1
Blue-blockers,
2 h preceding 
bedtime for 1  wk
lab visit
#2
Placebo lenses,
2 h preceding 
bedtime for 1  wk
lab visit
#2

the study. Participants with children <1 y-old will not be included. Women will not be pregnant or 
breastfeeding. CUMC research staff will be involved in the recruitment and enrollment efforts.  
 Individuals meeting inclusion criteria will be enrolled and randomized to receive either BB or 
placebo lenses in phase 1. Participants will be instructed to wear lenses each night, from 2 h 
before bedtime until lights out. Throughout the intervention, upon awakening participants will note 
their bedtime and waketime, and time of wearing lenses, on a sleep-log, and will complete a daily 
post-sleep questionnaire (PSQ). The PSQ entails quantitative estimates of SOL, total sleep time 
(TST), time awake during sleep episode, and number of awakenings, as well as ratings on a 7-
point scale of overall evaluation of sleep (1: extremely bad, 7: extremely good), soundness of 
sleep (1: extremely light, 7: extremely sound), current feeling of sleepiness (1: not sleepy at all, 
7: extremely sleepy), and current feeling of refreshed (1: not refreshed at all, 7: extremely 
refreshed) (42). This will allow us to confirm compliance with intervention and to collect data on 
ambulatory sleep quality and habits across the trial. During each intervention, participants will 
wear a wrist-mounted Actigraph GT3X+ to monitor TST, SOL, and sleep efficiency (SE).  At the 
beginning of the intervention, participants will complete a brief computer-based adaptive 
neuropsychological battery (NIH Toolbox Cognition Battery; www.nihtoolbox.org) to assess their 
functioning in the domains of executive function, attention, episodic memory, language, 
processing speed, and working memory. This assessment will last about 30 minutes. CUMC 
research staff will interact with participants and setup the study. 
Upon completing the 1-wk intervention, participants will be admitted to the Inpatient Unit at 
the Clinical Research Resource (CRR) of CUMC at ~18:00 for the lab testing period (Fig. 3). Upon 
admission, an in-dwelling forearm catheter will be inserted to allow continuous blood sampling 
which will not interrupt the sleep episode. Blood (3 ml/sample) will be collected continuously (1x/h) 
from 19:00-09:00 under “constant posture conditions”. Participants will remain in dim lights (<30 
lux) and in a semi-recumbent position during wakefulness. The sleep episode will occur in total 
darkness in a fully recumbent position. In lieu of meals, small isocaloric servings of BOOST Plus 
Complete Nutritional Drink (Nestle) will be served each hour during wake episodes. Participants 
will be asked to stretch their legs each hour while in the bed during the lab portion, without getting 
out of bed.  
Within the first 2 hours of arrival in the lab, participants will complete the Pittsburgh Insomnia 
Rating Scale-65 (PIRS65), which quantifies insomnia symptom severity. They will also repeat the 
same brief (~30 min) neuropsychological battery (NIH Toolbox Cognition Battery) administered at 
the intervention.  Each hour spent awake in the laboratory, participants will complete a 15-item 
visual analogue scale (VAS) to assess their levels of alertness, hunger, and appetite. CUMC 
research staff will interact with participants and conduct the study/collect data. 
Beginning 2 hours before the sleep episode, participants will be exposed to bright light (500 
lux) and will wear either BB or placebo lenses. The sleep episode will be scheduled based on 
their habitual sleep patterns during the previous week at home. They will have an 8-hour sleep 
opportunity in the lab. This will include a polysomnographic sleep recording. Upon awakening, 
participants will remain in bed in semi-recumbent position for the next 3 hours. Participants will 
complete the PSQ, and will resume the VAS scales, as well as have servings of BOOST Plus. At 

9:00, blood sampling will end and the catheter will be removed. Participants will be discharged at 
10:00. Blood samples will be analyzed for plasma content of melatonin (RIA, ALPCO, Salem, 
NH). After discharge, participants will begin a 4-week washout period. At the conclusion of this, 
they will cross over to the alternate lenses condition. The will be given the alternate lense type 
(BB or clear) and also the actigraph for the 7-day ambulatory tracking period. They will resume 
using the lenses 2-h before bedtime for 7 days, and completing the sleep-log and post-sleep 
questionnaires. After this, they will return to the lab for the second overnight visit. At the conclusion 
of the second overnight visit, they will have completed all experimental procedures.  
Statistical Procedures:  
Two-way within subjects ANOVA for repeated measures (factors: condition x time) will be used 
to analyze continuous melatonin, VAS, and neuropsychological values obtained during the 
laboratory visits. Simple main effects tests will be used to analyze significant interactions. Paired-
samples t-tests will be used to analyze single-value sleep parameters (subjective, actigraphic, 
and PSG), as well as sleep related questionnaires (PIRS65 and PSQ). Data will be tested for 
normality, and non-parametric equivalent tests will be used if data are deemed not normally 
distributed. Significance will be p<0.05