ABSTRACT

The Pupillary Light Reflex (PLR) is a fundamental physiological response; it is a reflexive constriction of the pupil in response to light stimulation, which is mediated by the autonomic nervous system (ANS). Traditional methods of evaluating the Pupillary Light Reflex (PLR) involves using a penlight to shine light into the eyes and observing the pupillary response. However, in recent years, smartphones with built-in flashlight have become increasingly popular, raising the question of whether smartphone flashlight can be used as an alternative to penlight for PLR evaluation. The study was aimed at comparatively assessing pupil size, latency and constriction amplitude using penlight and smartphone flashlight.This study follows an experimental study design carried out on 50 individuals between the ages of 16-50 years who visited the Optometry Teaching Clinic, University of Benin. The pupillary reflex of both eyes was tested using the two light sources and the results taken down using the assessment metrics.  The SPSS version 21.0 was utilized in analyzing the data obtained. Descriptive statistics was also used to analyse the data, and paired t-test was used as well to compare of pupillary response and determine statistical significance. The result showed significant differences in the consensual pupil size (p=0.000) and consensual constriction amplitude (p=0.000) in both eyes and a significant difference in the direct latency (p=0.000) in the left eye. Majority of the participants preferred the use of penlight against smartphone flashlight. In conclusion, the results of this study showed that the penlight is  more reliable and comfortable light source for pupillary light reflex evaluation when compared with the smartphone flashlight.

Keywords: Penlight, Smartphone, Flashlight, Reflex