Aspects are disclosed for determining refractive error. In an aspect, a line pattern is displayed to a user, and a distance between the line pattern and the user is ascertained. The line pattern includes a first and second line in which an aspect of the line pattern is varied, and where refractive error is quantified based on the distance and a selected variance of the line pattern. In another aspect, the varied aspect of the line is at least one of a width between the first and second line, a thickness of the first or second line, a darkness of the first line or the second line, or a color of the first line or the second line. An input corresponding to a focused line pattern variance selected by the user is then received, and a refractive error is quantified based on the input and an approximate distance between the line pattern and the user.