Painless and progressive, cataracts slowly cloud the lens. The first symptom of cataracts is often decreased night vision. The light distortion caused by cataracts also frequently produces halos around lights -- again, mostly at night. Blurry vision is also common.
sonata form. n. Music. A form of a movement consisting of three sections, the exposition, development, and recapitulation, often followed by a coda.
1 Some are in one movement; I know one symphony in 24 very short movements. Many composers have abandoned the usual forms altogether.  Variations on Sonata form in chamber music begin with Beethoven, who wrote some Piano Sonatas that are not really in Sonata form at all.