Estimation of pupil size using a digital camera
Avelino L. Zapanta Jr., MD, Jerome S. Sarmiento, MD, Carlos Alberto, MD, Monserat A. Zapanta, MD
Purpose
To compare pupil-size determination using a digital camera with the Rosenbaum-pupil-comparison and the millimeter-ruler methods.
Methods
The pupil size of 30 eyes of 15 medical students with a mean age of 27 years was measured by two examiners using a digital camera, Rosenbaum pupil comparison, and direct millimeter rule. Both examiners determined the mean pupil sizes for bright, dim, and dark settings.
Results
The mean pupil size as measured by both examiners at bright and dim light conditions was 5.6 mm (range 4.5 to 7.5) and 6.3 mm (range 4.5 to 8.0) respectively. The mean measurement for both examiners for dark is 7.0 (range 6.5 to 7.5). Only the digital camera was able to measure in dark setting with mean of 7.0 mm (range 6.5 to 7.5) for both examiners. Inter-examiner difference was lowest for the digital photography in all simulated settings.
Conclusion
The use of digital camera in determining pupil size was comparable to Rosenbaum chart and direct millimeter rule with lower inter-examiner differences.
Keywords: Digital camera, Pupil size, Rosenbaum pupil comparison.