Some eyes are more sensitive than others.
Testing your patient's solar sensitivity is important when they are selecting a shade for their sunglasses. The patient stands away from the meter and focuses on the target test pattern. At the point where the test pattern is no longer visible or the light intensity becomes uncomfortable, the patient releases the button. This triggers the meter to provide a percentage density which would be the recommended solar prescription. The patient's lenses can then be tinted in either your own or your lab's tinting system and then dispensed.