The short version
Just 3 companies supply this market — thin enough that a single exit would be felt immediately. The generic price has fallen 50% in a year, to $8.36 per mL — and generics that get this cheap tend to get abandoned rather than defended. The brand (Bepreve) runs $55.94 per mL — 5.7× more. Put together: worth watching — several of the pressures that precede supply trouble are present at once.
The numbers behind every sentence are on this page below — and the Watch button emails you when any of them move.