Understanding your Vision Results
When some doctors talk, it can get really hard to follow. There is usually a lot of jargon, abbreviations, and huge words that probably require a 6-year degree just to learn how to spell. And even when you do get an amazing doctor who breaks it down step by step, it can be a lot of information and hard to remember. This is all doubly true for eye exams. There is a lot to learn and sometimes you might not even know your own vision or even what’s normal, but we’re here to break that down for you.
What is 20/20 Vision?
We all know 20/20 is ideal, but what does that even mean? Basically, the top number is just your distance from the eye chart and the bottom number is what an average person can read the same line. So, if you have 20/20 vision you can read the same at 20 feet away as the average person. 20/40 means at 20 feet you can see what most people read 40 feet away.
For reference: California requires you to have at least 20/40 vision to drive without glasses/contacts, 20/80 is the average for people who need glasses and anything smaller than 20/200 is considered a severe visual impairment.
What do the Numbers Mean?
But when you look at your vision prescription it does not just say “20/80” it will have numbers for Sphere, Cylinder, and Axis and everything will be split by OD and OS... What are those all about?
OD refers to your right eye, OS refers to your left. Sphere or SPH refers to the “refractive power of your lenses,” which in English basically means, how messed up your eyes are. The numbers under SPH can be positive or negative, and the closer you are to zero the weaker your prescription is. Someone with 20/20 vision for example, would have a 0 for OD and OS under SPH. Cylinder (CYL) and Axis are for astigmatism. The numbers here again refer to what sort of lens power will be needed to correct the impairment.
To put it as simply as possible, the closer your SPH is to zero, the weaker your prescription. CYL and Axis are for astigmatisms and refer to the amount of correction your glasses will need.
There are other things that can be listed such as “ADD” (additional magnification) and “Prism,” but these are individual to you and should be explained by your optometrist.
So, what exactly is Nearsighted or Farsighted?
Nearsighted means you can see close up, but not far away. Farsighted is the opposite. This can happen for any number of reasons, but the number one cause is age. One isn’t better than the other and they each are corrected with glasses or contacts.
If you are having issues with your eyesight, it is highly recommended to get a prescription as blurry vision can lead to migraines and eye strain.
It is a myth that glasses or contacts weaken your eyes. They actually slow the degradation of your eye health. Wear them if you need them!
Astigmatism? What’s a Refractive Error?
Astigmatism is when your eye has trouble focusing light. This causes blurry vision. If you look at a streetlight or taillight of a car and see long blurry lines or if lights have a very dramatic halo, that means you have astigmatism. These blurry lines and halos are “refractive errors” so that’s what an optometrist means when they refer to them!
You treat astigmatisms by wearing cylindrical lenses. These lenses can be squares, ovals, or cylinders.
Ultimately, eye health is extremely important! And while there might be tons of numbers flung around, it’s necessary to get your annual eye exam to make sure you are getting the help you need.
If you’re an SDPEBA member with VSP or are interested in our VSP plan, check out this page for more information!