I'm trying to find information on any rare diseases associated with light. Preferably diseases which can be fatal, although in my story the conditions of the medical facilities are so bad that almost anything would be fatal eventually.
There aren't many limitations to the conditions I'm looking for. I know all about albinism, and I also discovered a disease called xeroderma pigmentosum, which fits my criteria nicely. I've also found some info on photophobia and the diseases associated with it, but I'd really like to know about any other rare/serious diseases associated with light. Severe psychological conditions might fit too.
Additional info: The story is set in a futuristic Earth, where the entire population worships an entity called The Light, so any condition which involves an adverse reaction to light is seen as 'satanic'. Like I've said, I've found a fair amount on the more common (and less light-specific) conditions, but I really need something practically unheard of - hence the issues with finding it! - as well as a good selection of other illnesses to plague my characters with.
I've searched Google with a mix of terms I've used in this post - light, adversion, disease, rare disease, etc, and all it came up with was XP. I've also looked on wiki, which was equally unhelpful, and I've browsed several medical websites including wrongdiagnosis.com (which kept directing me to 'light vaginal bleeding' o_O).
If there's nothing else out there that actually exists, I'm sure I can invent fictional conditions, but thanks in advance for any help!