Aland Island Disease

Hi,

My son, who is 4, has just been diagnosed with Aland Island disease.
The hospital didn't really give us much information about what this
actually is, and more importantly what it means short and long term
for my son. The research I have done on the web throws up lots of very
technical terms which I am struggling to interpret - I think it is
related to incomplete congenital stationary nightblindness - which is
slightly simpler to understand (but not much!).

Is anyone able to explain what it means in lay terms please?

Thank you.

.