While Glance can adapt to many levels of ambient light, its performance may be affected under certain circumstances. This article describes some of the possible scenarios where a decrease in performance can occur.
Generally speaking, strong levels of sunlight may have an adverse effect on Glance's ability to adequately track your presence and/or attention.
Environments where a large amount of direct sunlight is being projected directly towards your Glance equipped screen, whether it is from behind you or from the side, would be the most problematic.
However, moderate amounts of sunlight, or diffuse sunlight, should have little to no impact on Glance.
Artificial Light Levels
Unlike sunlight, a large amount of artificial light will not affect Glance in a significant way. The only exception to this would be a very concentrated source of artificial light positioned behind your head as you use Glance.
Also, extremely low amounts of artificial light, such as complete darkness, may also diminish Glance's performance.