You can also try and integrate over time. Complex? Definitely. Not an exact science because you will have to estimate the motion of both the eyeball and the subject you are trying to identify? Yes (in most cases). Feasible? In some cases: probably.

And that, too, will get better with better hardware. At first, you may only be able to detect hair color and rough hair length in cases where the person being identified has a nice silhouette against an evenly lit sky, but that already is something.