| Sumario: | Purpose: To measure the amount of day game (natural) and night game (artificial) illuminance at home plate at the lateral canthi and to determine if day game pupil diameter can be simulated by artificial light levels at night. Methods: Twenty-two subjects stood at home plate, wore a baseball cap, and looked at a distance target (60.5 feet away) while five photos were taken during each scenario. Illuminance was then measured three times at home plate and at each lateral canthi. Three day game and night three game images, of the same eye, were filtered to enhance pupillary margins. Diameters were measured using Adobe Photoshop CS4. A paired sample t-test was used to compare day-night pupil diameters and illuminance. Results: Mean day game pupil diameter and standard deviation was 2.58 ± 0.45 mm. Night game diameter mean ± SD was 6.45 ± 1.11 mm. The mean ± SD diameter increase was 3.87 ± 1.14 mm (P<0.001, r=0.120). Average day game illuminance (foot-candles) measurements were: Home plate = 3907.62, OD = 4505.87, OS = 4096.77. Average night game illuminance measurements were: Home plate = 12.11, OD = 5.60, OS = 5.23. Day game illuminance measurements between home plate and each canthus were not found to be statistically significant (POD=0.344, POS=0.751), but were for night game measurements (POD=<0.001, POS=<0.001). Conclusion: Significantly less light is available to the eye during artificially lighted night game scenarios than during naturally lighted day game scenarios. The magnitude of this difference depends on where illuminance is measured. Subjects experienced a change in pupil diameter at night consistent with earlier studies.
|
|---|