Why does my prescription look so different?

There are multiple debates in eye care, but one of the longest standing is plus versus minus cylinder when writing glasses prescriptions. Optometrists tend to prefer minus cylinder, and ophthalmologists prefer plus cylinder. What does this mean? It means that your glasses prescription can look very different, depending on who writes it.

For example:

+5.00-3.00x010 means that at axis 10, the prescription is +5.00, and 90 degrees away at axis 100, the prescription is +5.00-3.00 which is +2.00.

+2.00+3.00x100 means at axis 100, the prescription is +2.00, and 90 degrees away at axis 10, the prescription is +2.00+3.00 which is +5.00.

Both of these prescriptions mean +5.00 at axis 10 and +2.00 at axis 100, but are written two different ways.

A patient may see +5.00 on the first prescription and +2.00 on the second prescription and assume there is something incorrect, when in reality, the prescriptions are exactly the same. The axis is also written 90 degrees apart.

If you receive a prescription that appears drastically different than a previous prescription, the first thing you should check is whether the math of the prescription is written as MINUS or PLUS.