Dictionary.com
definitions

optometry

[op-tom-i-tree]

noun

the practice or profession of examining the eyes, by means of suitable instruments or appliances, for defects in vision and eye disorders in order to prescribe corrective lenses or other appropriate treatment.

Origin of optometry

First recorded in 1890–95; opto- + -metry
Related formsop·to·met·ri·cal [op-tuh-me-tri-kuh l] /ˌɒp təˈmɛ trɪ kəl/, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
British Dictionary definitions for optometry

optometry

noun

the science or practice of testing visual acuity and prescribing corrective lenses
Derived Formsoptometric (ˌɒptəˈmɛtrɪk), adjective
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Word Origin and History for optometry
n.

1886, from optometer (1738), an instrument for testing vision, from opto- "sight," from Greek optos "seen, visible" (see optic) + -metry. Probably influenced by French optométrie.

Online Etymology Dictionary, © 2010 Douglas Harper
optometry in Medicine

optometry

[ŏp-tŏm′ĭ-trē]

n.

The health care profession concerned with examination, diagnosis, and treatment of the eyes and related structures, and with determination and correction of vision problems using lenses and other optical aids.
Related formsop•tom′e•trist n.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.