Girl in the dark : a memoir / Anna Lyndsey.

Enhanced descriptions from Syndetics:

A gorgeous memoir of an unthinkable life: a young woman writes of the sensitivity to light that has forced her to live in darkness, and of the love that has saved her.
 
      "Something is afoot within me that I do not understand, the breaking of a contract that I thought could not be broken, a slow perverting of my substance."

     Anna was living a normal life. She was ambitious and worked hard; she had just bought an apartment; she was falling in love. But then she started to develop worrying symptoms: her face felt like it was burning whenever she was in front of the computer. Soon this progressed to an intolerance of fluorescent light, then of sunlight itself. The reaction soon spread to her entire body. Now, when her symptoms are at their worst, she must spend months on end in a blacked-out room, losing herself in audio books and elaborate word games in an attempt to ward off despair. During periods of relative remission she can venture cautiously out at dawn and dusk, into a world that, from the perspective of her normally cloistered existence, is filled with remarkable beauty.
    And throughout there is her relationship with Pete. In many ways he is Anna's savior, offering her shelter from the light in his home. But she cannot enjoy a normal life with him, cannot go out in the day, and even making love is uniquely awkward. Anna asks herself "By continuing to occupy this lovely man while giving him neither children nor a public companion nor a welcoming home--do I do wrong?" With gorgeous, lyrical prose, Anna brings us into the dark with her, a place from which we emerge to see love, and the world, anew.