Cataracts

I am sitting here with one eye blacked out as a result of a cataract operation performed yesterday by the ophthalmologist. (Now there's a tongue-twister of an occupation. Not easy to know what he might do for a living. Not like, take for example, candle-stick-maker. One knows straight away what he does.) This present situation brought to mind my recent visit to Launceston and its premier tourist attraction – the Cataract Gorge. I also have in the back of my mind that someone once told me I had gorgeous eyes. I think gorgeous was the word used!
Isn't it one of those strange quirks of language that a word (here: cataract) should have two widely different meanings with no apparent connection? Why should the medical condition of my eyes where the lenses become clouded over be called the same as water rushing over some impediment?
It seems that the etymologists (they don't make candles either!) can't answer this question satisfactorily either. One online etymology dictionary (www. etymonline.com) gives: “1430, from L. cataracta “waterfall”, from Gk. Katarhaktes “swooping, rushing down,” from kata “down” + arhattein “to strike hard.” Its alternate sense in L. of “portcullis” was probably passed through M.Fr. to form the E. meaning “eye disease” (1547), on the notion of “obstruction.” “ These etymologist people seem to write in a special sort of language.
My theory is simply that the crystal clear stream becomes opaque when it tumbles through a cataract. Maybe all will become clear to me when my eye recovers. I probably first came across cataracts in my early geography lessons where one learned about the cataracts on the Nile river. There was the first cataract, the second, and so on. I can't quite remember exactly how many there were. Which is purely academic for they made a DAM mess of them years ago.
My photo below shows some quiet water in Launceston's Cataract Gorge and the one above some opaque water at the foot of the Krimmel waterfall, Austria's highest. And no, I don't think anyone has ever told me I have (or even HAD) gorgeous eyes.