| Answer | Crossword Clue |
|---|---|
| opsiometers | OPSIOMETER, an instrument for testing vision |
| opsiometer | an instrument for testing vision |
| optometers | OPTOMETER, an instrument for testing vision |
| lactometer | an instrument for testing the relative density of milk |
| optometers | An instrument for testing the refractive power of the eye |
| lactometers | LACTOMETER, an instrument for testing the relative density of milk |
| optometer | An instrument for testing the refractive power of the eye |
| planometer | an instrument for gauging or testing the flatness of a plane surface |
| planometers | PLANOMETER, an instrument for gauging or testing the flatness of a plane surface |
