Definition of optometer in English:

optometer

noun

  • An instrument for testing the refractive power of the eye.

    • ‘We have developed an optometer to measure the ocular astigmatism of human eyes and tested its performance.’
    • ‘He immediately became hypermetropic (long sighted) in that eye, but using his optometer found ‘the same inequality in the horizontal and vertical refractions as without the water’.’

Origin

Mid 18th century: from Greek optos seen + -meter.

Pronunciation:

optometer

/ɒpˈtɒmɪtə/