When you take a gander at your prescription for eyeglasse s , you will see numbers recorded under the headings of OS and OD. They are Latin contractions: OS (oculus evil) implies the left eye and OD (oculus dextrose) implies the correct eye. Once in a while, you will see a documentation for OU, which implies something including both eyes. As a rule, the further far from zero the number on your prescription, the more regrettable your visual perception and the more vision remedy you require. An or more sign before the number means you are farsighted and a short sign means you are partially blind. These numbers speak to diopters, the unit used to gauge the rectification, or centering force, of the focal point your eye requires. Diopter is frequently shortened "D." For instance, if your prescription says - 1.00, you have one diopter of astigmatism. This is a genuinely mellow measure of partial blindness. In the event that you are - 4.25, that implies you have 4 and...