ArticleCurrent eye research2026
Classifying Indoor Versus Outdoor Environments Using the Actiwatch Spectrum PRO | A 1000 Lux Threshold is Questionable.
Article in Current eye research, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 2 papers.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
2 citing papers in PubMed.
- Validation of a Multimodal Wearable Device for Assessing Environmental and Behavioral Risk Factors of Myopia in Children and Adolescents.Ophthalmic & physiological optics : the journal of the British College of Ophthalmic Opticians (Optometrists) · 2026Article
- Annual Solar Cycles: Investigating Seasonal Variations in Southern Norway and Their Potential Role in Human Eye Growth.Investigative ophthalmology & visual science · 2026Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
4 authors.
Funding
Abstract
introductionWearable light sensors allow for a more objective classification of a child's habitual light environment. The aim of this study was to develop an optimal illuminance and/or RGB irradiance thresholds as a proxy for distinguishing between indoor and outdoor environments through empirical analysis of data collected with the Actiwatch Spectrum PRO, as an example of wearable light-sensing technology.
methodsSix participants, aged 18-22 y, wore an Actiwatch Spectrum PRO, for two consecutive days as they went about their daily activities. The Actiwatch was configured to record at 30 s epochs, both overall illuminance (lux) and irradiance (µW/cm2), for each of its three wavelength channels (R, G, B). Using the Actiwatch's scoring feature, participants indicated changes in their environment and its type, i.e. indoors or outdoors. For each individual dataset, mean illuminance, as well as mean red, green, and blue irradiances were calculated for each event, i.e. interval spent in a particular environment. Criteria for distinguishing between indoor and outdoor environments were evaluated using ROC analyses.
resultsBased on the collected data, a 1000 lux white light threshold, which has been commonly used to distinguish between outdoor and indoor settings, resulted in significant misclassification of reported outdoor events (sensitivity: 43.5%, specificity: 93.6%). The use of two time-dependent red light irradiance thresholds covering sunrise to 2 pm, and 2 pm to sunset, proved to more reliably identify outdoor settings (sensitivity: 85.1%, specificity: 82.6%).
conclusionIn this small-scale study of the Actiwatch Spectrum Pro, derived red light irradiance thresholds out performed the more commonly used 1000 lux white light threshold in correctly classifying indoor and outdoor environments. In this context, the potential utility of wavelength-dependent irradiance cutoff values warrants further investigation, with due consideration to study-specific differences in geographic locations, climate and season.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.