Inspired by a fellow visually-impaired photographer on Flickr (see the image of Sandra on the right), I went to my local outdoors store and bought an LED headlamp, the Tikka Plus, from Petzl. The headlamp is great for reading! I have been using booklights to supplement ambient room lighting for a while now, but have never been satisfied. My eyesight forces me to hold the book quite close, so these booklights are often obstructed by my own forehead. While the headlamp is not perfect, it is a significant advance in convenience and quality.
Personally, I would prefer a more diffuse light and one with more low intensity options. The light is designed to throw a wide beam outdoors or in caves, so the light hitting a page a few inches a way works more like a spotlight. I will experiment with some ways to diffuse the light a bit, possible some opaque paper, bu tI already look geeky enough with it on.
Hopefully, someone will come out with a headlamp designed specifically for the visually impaired, or at least for home honnyists whose need for close up lighting is similar. I have contacted Petzl with the suggestion.
Addendum: I have found a web site that has a headlamp specifically for the visually impaired। I can not say anything more about the lamp or the site as I have had no experience with either. Leave a comment if have any thoughts.