Snellen Chart Distance: Setting Up an Exam Lane at 20 Feet, 6 Meters or Less

The standard Snellen chart distance is 20 feet in the US and 6 meters in metric practice. That is the...

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How to Use a Phoropter: A Step-by-Step Guide to the Controls

Knowing how to use a phoropter comes down to running its controls in a fixed order, every time: level the...

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