A novel phone application (SOBER-EYE) was developed to quantify measures of pupillary light reflex (PLR) that extends beyond traditional PLR dichotomous measurement techniques. Prior to implementation into clinical practice, the test–retest reliability must be evaluated. The primary outcome measure was the intraclass correlation coefficient. Intraclass correlation coefficients for two PLR trials included: constriction amplitude (.825), constriction velocity (.693), initial pupil diameter (.888), latency (.962), and minimum size (.851). Clinical utility was found as all intraclass correlation coefficient values were >.60. The SOBER-EYE phone app has the potential to be used in the clinical environment to assess PLR.