How does an optician interpret the ophthalmologist's prescription?

Very little needed.: There is very interpretation necessary when an optician receives a glasses prescription. There are specific values on the prescription (sphere, cylinder, axis, bifocal power, prism) from the refraction of your eye exam, and should not be changed. The optician makes sure that the frames are adjusted properly for you and checks the pupillary distance so that the lenses are centered properly.

Reading a glasses Rx: A glasses rx typically has information on each eye. Od means right eye. Os means left eye. The first number is the power of the lens, minus for near-sighted or positive for far-sighted. The second number is the astigmatic power if present. The third number is the axis or direction of the astigmatism correction. The optician uses this information to carve a lens blank to the specified rx.