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Normal pupillary size in fluorescent and bright light.
Michael D Witting1, Deepi Goyal
1Division of Emergency Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA. mwitt001@umaryland.edu
Annals of Emergency Medicine
|January 28, 2003
Summary
Normal pupillary size ranges were defined in two lighting conditions. Sizes outside 2.6-5.0 mm in dim light or 1.9-3.6 mm in bright light are rare in healthy adults.
Area of Science:
- Ophthalmology
- Clinical Measurement
Background:
- Pupillary size is a common clinical measurement.
- Previous descriptions of normal pupillary size ranges are imprecise.
Purpose of the Study:
- To precisely define the distribution of normal pupillary sizes.
- To establish normal ranges in two clinically relevant lighting conditions: ambient fluorescent and bright direct light.
Main Methods:
- Pupillary sizes were measured in 128 healthy adults using a modified Haab scale.
- Measurements were taken under standardized fluorescent lighting (2,700–5,400 lux).
- Measurements were also taken using bright handheld light sources (>54,000 lux), with different devices tested.
Main Results:
- Mean pupillary size was 3.6 ± 0.7 mm in fluorescent light and 2.6 ± 0.5 mm in bright light.
- In fluorescent light, 5th-96th percentile range was 2.6–5.0 mm.
- In bright light, 3rd-96th percentile range was 1.9–3.6 mm; light source type did not affect results.
Conclusions:
- Pupillary sizes outside 2.6–5.0 mm in fluorescent light are rare (<10%) in healthy individuals.
- Pupillary sizes outside 1.9–3.6 mm in bright light are rare (<10%) in healthy individuals.