Reading vision screening results involves understanding the various metrics and tests used to assess visual acuity and other aspects of vision. And how to read vision screening results?

1. Visual Acuity

Visual acuity measures the sharpness of vision. The most common format for reporting visual acuity is the Snellen fraction (e.g., 20/20).

Snellen Fraction (20/20):
The first number (20) represents the testing distance, usually 20 feet.
The second number indicates the smallest line of letters that the person can read. A result of 20/40 means the person sees at 20 feet what a person with normal vision sees at 40 feet.
20/20: Normal vision.
20/40: Below average; might need corrective lenses.
20/200: Legally blind in the U.S. if this is the best corrected vision.

2. Refractive Errors

Refractive error measurements are often provided in diopters (D) and indicate nearsightedness, farsightedness, and astigmatism.

Myopia (Nearsightedness):
Negative values (e.g., -2.00 D) indicate difficulty seeing distant objects clearly.
Hyperopia (Farsightedness):
Positive values (e.g., +1.50 D) indicate difficulty seeing close objects clearly.
Astigmatism:
Cylinder (CYL) values (e.g., -1.25 D) indicate the degree of astigmatism.
Axis (0 to 180 degrees) specifies the orientation of astigmatism.

3. Binocular Vision

Tests for binocular vision assess how well the eyes work together.

Stereoacuity (Depth Perception):
Results are measured in arc seconds (e.g., 40 arc seconds). Lower values indicate better depth perception.
Cover Test:
Detects eye misalignment (strabismus). Results might indicate whether the eyes are aligned or if there is any deviation (e.g., esotropia, exotropia).