Reliability of the Smart Bulb and Comparison to the Lux IQ
Maude Gravel1, Marilou Sibley1, Elliott Morrice2,3, Caitlin Murphy1,2,3 & Aaron Johnson2,3
1School of Optometry, University of Montreal, 2Department of Psychology, Concordia
University, 3CRIR/Lethbridge-Layton-Mackay
Rehabilitation Centre du CIUSSS du Centre-
Ouest-de-l’Île-de-Montréal
Background
More than 5.5 million Canadians with visualimpairment
• >60% referred to vision rehabilitation have difficulties with reading
There is a general agreement stating that visual acuityimproves with increasing illumination
• Performance is better at all levels if contrast isincreased.
The type of lighting and its intensity, color and direction all affect an individual’s visual performance
Each person responds differently to light;
• Therefore appropriate lighting must beassessed.
Statistics Canada, 2018, Wittich et al., 2018
Characteristics of Light
Brightness:
Hue:
Temperature:
Participants
Questionnaires and Screening Tools
Questionnaires
● Informed Consent● Language Background Questionnaire
Screening Tools
● Montreal Cognitive Assessment (MoCA)● Freiburg Visual Acuity & Contrast Test (FrACT)● Hardy Rand and Rittler (HRR) Plates
Testing Procedure
Lux IQ
● 10 IReST text + practice text● Adjustments using the
practice text prior to the startof each trial.○ Settings go back to
recommended start point according to LuxIQ protocol: 500lux & 6500K
Smart Bulb
● 10 IReST text + practice text● Adjustments using the practice
text prior to the start of each trial.○ iPad: Light parameters
(brightness, temperature and hue)
○ Distance between the light source and the text
Settings remained the same for the duration of the trial
Descriptive Statistics
Lux IQ Smart Bulb
Reading Speed
(words/minute)
Mean: 215.1 ± 20.7
Range: 168.0-251.3
Mean: 207.5 ± 28.78
Range: 148.5 - 281.9
Number of errors Mean: 0.95 ± 0.82
Range: 0 - 3
Mean: 1.90 ± 1.46
Range: 0 - 7
Brightness (lux) Mean: 953.3 ± 526.1
Range: 500 - 3400
Mean: 103.8 ± 78.58
Range: 6.39 - 342
Temperature (K) Mean: 5494 ± 1011
Range: 545 - 6550
Mean: 3731 ± 1699
Range: 2287 - 1.45e+4
Linear Regression
Lux IQ Smart Bulb
R value 0.181 0.575
R2 value 0.0327 or 3.27% 0.330 or 33.0%
Correlations
Lux IQ Smart Bulb
Reading Speed and
Brightness
p = 0.620 Not
Significant
p = <.001 Significant
Reading Speed and
Temperature
p = 0.135 Not
Significant
p = 0.685 Not
significant
Brightness and
Temperature
p = 0.135 Not
Significant
p = 0.025 Significant
F(9, 35.93) = 22.83
p < 0.001*
F(9, 36.18) = 28.23
p < 0.001*F(9,36.6)=0.205
p=0.992
F(9,31.1)=0.788
p=0.629
Brightness & Temperature Across Participants
Lux IQ Smart Bulb
IntraclassCorrelations
Lux IQ
Brightness
ICC 0.967
Temperature
ICC 0.745
Brightness
ICC 0.745
Temperature
ICC 0.970
Smart Bulb
Independent t-Test: Lux IQ v Smart Bulb
Reading Speed
t(159)=1.92, p=.057
Brightness
t(198)=15.97, p<.001*
Temperature
t(188)=8.80, p<.001*
Discussion & Conclusion
No correlation between reading speed and the Lux IQ parameters
Bias protocol leading to cooler and brighter parameters
No correlation between reading speed and the light device used
Brightness and temperature selecion was more consistent with the Smart Bulb
Smart BulbCheaper than Lux IQ (20-140$ v. 1500$ CAD)All parameters can be modified using an appCan be installed with many different types of lamps
Next step: To evaluate both light devices in older individuals with & without visual impairment
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