You’re not wrong!
What’s going on is that, while the definition of albinism in mammals is pretty firm (it gets murky in other animals because melanin isn’t their only pigment) there are multiple kinds of albinism, medically speaking, differentiated by the genetic mutations that cause them. Oculocutaneous albinism is the most common kind and there are different types of that based on what genes are mutated. As for the red eyes, recall that I said Lady Aldreda has oculocutaneous albinism type 2. What you’re thinking of is type 1.
OCA2 is caused by a mutation of the OCA2 gene (named after the thing the mutation causes!) on Chromosome 15, a gene that codes for melanocyte-specific transporter protein. I could explain the biochemistry a bit more, but what it amounts to is a drastically decreased production of melanin, but the body does still make some, and melanin gives the iris its color. Large amounts of melanin result in brown eyes, while very small amounts, like in OCA2, result in icy blue eyes. OCA2 is the most common form of albinism, occurring in either 1in 20,000 or 1 in 15,000 births (sources vary slightly)
OCA1, on the other hand, is far rarer (1 in 40,000 births), but is probably the most iconic form of albinism, caused by a mutation of the TYR (tyrosinase) gene on Chromosome 11. People with OCA1 don’t make any melanin, not even in their eyes. As a result, the iris is transparent, and you can see the red blood in the retina through the iris, hence the red color. I actually wanted Lady Aldreda to have OCA1 in my initial planning stage, as I thought the red eyes would look cool, factor into the negative reactions to her and contribute to her exotic beauty (there probably would have been a bit during Elis’s description of Aldreda talking about her striking ruby-colored eyes) but I ran into a problem.
You see, melanin doesn’t just color your iris or help keep your skin from being hurt by the sun. It’s actually important in the development of multiple parts of the eye, including the iris, retina, optic nerve and eye muscles, so a total lack of the chemical has adverse effects on vision. People with OCA2 may sometimes suffer from problems with bright lights, but people with OCA1 have it far worse. You’ve heard of 20/20 vision? Well, people with OCA1 can have 20/200 or even 20/400 vision. They’re not blind, but it’s a pretty severe impairment. This wouldn’t necessarily hinder Lady Aldreda’s melee capability (she could compensate for decreased vision with her other senses), but I also wanted her to be good with her crossbow, and she needs sight for that.
Thank you again for the compliment, and I’m sorry for the biology lesson I just gave you above.
Well, given that this is sort of a retelling of the story, when you mentioned the Great Fog of ‘64, I figured it might be a reference and did some research. By the time you mentioned ‘39, I knew what that was about.
Oops! Had that backwards...