1. A computer-implemented method of performing a specified ophthalmologic assessment, the method comprising: receiving an input specifying subject information on a handheld computing device; capturing an image, using an image-capturing device of the handheld computing device, containing a left eye pupil and a right eye pupil of a subject; analyzing the image captured on a processing unit of the handheld computing device to determine a position of the left eye pupil of the subject and a position of the right eye pupil of the subject in the image captured; measuring, using the processing unit, an interpupilary distance between the position of the left eye pupil and the position of the right eye pupil; determining, using the processing unit, a distance from the image-capturing device to a subject's eyes based on a comparison of the interpupilary distance measured with a predetermined interpupilary distance corresponding to the subject information; determining whether the distance determined is within an appropriate distance range for performing the specified ophthalmologic assessment; and in response to a determination that the distance determined is not within the appropriate distance range, causing the handheld computing device to perform a remediation action.