Akademik

Letters of various sizes used to test visual acuity.

- Jaeger t. type of different sizes used for testing the acuity of near vision.

- point system t. a near-vision test chart in which the various t. are multiples of a point (172 inch), lower-case letters being one-half the designated point size; reading 4-point at 16 inches is normal, and is designated N-4.

- Snellen t. square black symbols employed in testing the acuity of distant vision; the letters vary in size in such a way that each one subtends a visual angle of 5′ at a particular distance.