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Also question is, what does CF mean in vision?
counting fingers
Diopter Measure | 20/20 Measure |
---|---|
-1.00 | 20/40 |
-2.00 | 20/80* |
-3.00 | 20/150* |
-4.00 | 20/300* |
Keeping this in view, what do vision numbers mean?
An eye chart measures visual acuity, which is the clearness or sharpness of vision. The top number is your distance in feet from the chart. The bottom number is the distance at which a person with normal eyesight can read the same line. For example, if you have 20/30 vision, it means your vision is worse than average.
Visual acuity is usually measured with a Snellen chart. Snellen charts display letters of progressively smaller size. "Normal" vision is 20/20. This means that the test subject sees the same line of letters at 20 feet that person with normal vision sees at 20 feet.