Sensitive Eyes (3.5e Trait)
From D&D Wiki
Light stings your eyes, but you see better in the dark.
Prerequisite: Cannot already have any other form light-sensitivity.
Benefit: You gain 30 feet of Darkvision.
Drawback: The character's eyes become sensitive to sunlight, sometimes other forms of light as well, and are dazzled by sunlight.
Roleplaying Ideas: The character could choose to stay inside more often, and perhaps become more reclusive.