Mr. linton wants to determine from what distance sam can discriminate letters or numbers written on the board. he should measure sam's

Visual acuity

Explanation:

Visual acuity is the eye's ability to distinguish spatial details, that is, to identify the outline and shape of objects. Understanding a person's degree of visual acuity is nothing more than measuring their functional ability to see. That is, the better and less difficult the person can complete the visual acuity test, the easier it is to see and the better the visual acuity.

There are two tests that can measure a person's visual acuity. The most popular of these is the one that uses the Snellen Chart as its exam base. Easy to find in many eye clinics, the table is made up of several lines filled with letters or numbers, which gradually reduce in size and are at a distance from the patient. The test is based on the patient's ability to distinguish these letters and numbers, similar to the test Mr. Linton is practicing on Sam.