4 ms·
It's 20/20 and is used in ophtalmology to express dioptry: 10/10 is perfect vision and 20/20 is elven or hawk eye sharp, beyond human eyes' capability.
by Annatar 8y ago
It's 20/20 and is used in ophtalmology to express dioptry: 10/10 is perfect vision and 20/20 is elven or hawk eye sharp, beyond human eyes' capability.