Hey there,
Lupus can certainly cause all kinds of eye troubles, but I've never heard anything about it being able to cloud one's lenses.
It is my understanding that cloudy lenses are sometimes a sign of cataracts (amongst a lot of other things), though of couse cataracts usually have noticeable symptoms that go along with the lens clouding (i.e. blurry vision et cetera).
Has Serena been on steroids for a long time? I do remember my doctor mentioning needing to get one's eyes checked for caractacts and/or increased eye pressure a couple of years ago after I'd gotten iv steroids a couple of times. Does she see an opthamologist for her yearly plaquenil eye checks? If so then he would have picked up on anything that might have been going on with her eyes. If she gets her checks at the optometrist's it might be an idea to mention this to the gp or rheumy when you next see them and see if they think you should investigate more (ie. by going to an eye doc for a check-up) or not.
Do bear in mind that this might be something that Serena just happens to have, something that might be perfectly normal for her and that it isn't something necessarily abnormal. I have a blue patch in the sclera of my right eye and I was bounced from eye specialist to eye specialist in my teens when if first appeared as they were all quite impressed with the odd colouring and didn't know whether it signified anything sinister or not. Well, after hearing some fancy and strange eye (and bone amazingly!) disease names flying about, turns out it's just a harmless blue patch in my eye :lol: !
Hope you and Selena are doing ok,
Zoi