Variation of Ambient Illumination Across Different Locations: An Impact on Antimyopia Strategy.
Level 4 - case-series / case-control
Cross-sectional environmental measurement study evaluated by design analogy.
PubMed 39959594 · doi:10.4103/meajo.meajo_135_23
What was done
Illuminance was recorded in winter across 6 outdoor locations (open playground, between two buildings, between three buildings, under a porch facing east, under a big tree, under a porch facing west) and 5 indoor locations (rooms with multiple large windows, combination light sources, single artificial light, multiple artificial lights, canopy covering buildings) using a factory-calibrated digital lux meter under varying times of day, weather conditions (sunny vs. foggy), source positions, and sun protection.
What was found
The median illumination was 1900 lux (range 803–4300 lux) across outdoor locations and 227 lux (range 82–556 lux) across indoor locations. Indoor locations generally stayed below 1000 lux, although rooms with multiple large windows exceeded 1000 lux during specific intervals (10:00–11:00 and 13:00–14:00) in both sunny and foggy weather. The open playground consistently had the highest illumination level across all tested conditions.
Why it matters
The findings demonstrate that open outdoor settings in winter consistently meet the 1000-lux threshold commonly proposed for antimyopia strategies, while indoor settings rarely do.
Limits
No human participants or myopia progression outcomes were evaluated. The geographic location, specific latitude, and sample size of individual light measurements are not reported in the abstract, and observations were restricted to winter conditions.
Cited by
- supports Outdoor light lux intensity on a cloudy day substantially exceeds the lux intensity of indoor building lighting.