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.
The first movement of a symphony usually has a structure called sonata form. Sonata form is simple, and understanding it will enhance your appreciation of almost all classical music. What follows is simplified further still, but it applies to the first movement of most classical symphonies.