That's an interesting question. There are several components to vision. For example, how sharp you see things is referred to as visual acuity. This is not just determined by your eye (the retina, more specifically), but is also a function of the visual cortex in your brain! Another useful component of vision is depth perception. This means how well you judge how close or far things are compared to their actual distances in the physical world.

Individuals with lighter eye color might be more sensitive to brightness. However, this probably does not affect things like visual acuity or depth perception.

No, the color of the pigment in your iris has nothing to do with your vision. Any light that is not reflected by the pigment is absorbed in the iris, and does not reach your retina.