Systems and methods are disclosed to enable performance of a lens distance test in head-mounted displays (HMDs) to determine the distance between a user's eye and a lens of the HMD (e.g. the display lens in a virtual or augmented reality device). In embodiments, the HMD is configured to determine a current pose of the eye based on a series of captured eye images. The pose information is used to determine the distance from the apex of the cornea to a closest point on the lens. If the determined distance is too small or too large, an alert or notification is generated instructing to adjust the HMD or change the light seal to achieve better distancing, in order to reduce the risk of eye injury and/or improve user experience. In embodiments, the lens distance test may be repeated during a user session to reevaluate and/or monitor the lens distance.