If you have received an eye prescription from Dr. Ngoddy, you may have wondered what all the numbers and abbreviations mean. Eye prescriptions look confusing at first, but they are actually quite simple once you understand what each part means. This guide explains every element of your prescription so you know exactly what your doctor determined about your vision.
If you have received an eye prescription from Dr. Ngoddy, you may have wondered what all the numbers and abbreviations mean. Eye prescriptions look confusing at first, but they are actually quite simple once you understand what each part means. This guide explains every element of your prescription so you know exactly what your doctor determined about your vision.
Sample Eye Prescription
Here is what a typical eye prescription looks like:
OD (Right Eye)
Value
Sphere (SPH)
-2.50
Cylinder (CYL)
-0.75
Axis
180
Add
+2.00
OD (Right Eye)
Value
Sphere (SPH)
-2.50
Cylinder (CYL)
-0.50
Axis
175
Add
+2.00
Understanding Each Part of Your Prescription
OD and OS
OD stands for "Oculus Dexter" which means right eye
OS stands for "Oculus Sinister" which means left eye
You may also see "OU" which means both eyes
Sphere (SPH)
The sphere is the basic lens power needed to correct your vision. This number corrects either nearsightedness or farsightedness.
Negative numbers (like -2.50) mean you are nearsighted. You have trouble seeing things far away, but see clearly up close.
Positive numbers (like +2.50) mean you are farsighted. You have trouble seeing things up close, but see clearly far away.
Zero or no number means you do not need correction for nearsightedness or farsightedness.
Cylinder (CYL)
The cylinder value corrects astigmatism, which is an irregularity in the shape of your cornea that causes blurred vision at all distances.
If there is no cylinder value listed on your prescription, you do not have astigmatism.
If there is a cylinder value, the number is always negative and is usually smaller in magnitude than your sphere number.
Axis
The axis is a number from 1 to 180 that indicates the direction of astigmatism in your eye. Think of it like the hand on a clock showing the angle of the astigmatism.
You will only see an axis number if you have astigmatism. If you do not have astigmatism (no cylinder value), there is no axis.
Add Power
The "Add" is additional power used in bifocals, trifocals, or progressive lenses for reading or other close work. It is typically a positive number like +1.50 or +2.00.
You will only see an Add if you need correction for presbyopia, which is difficulty focusing on close objects (usually after age 40).
What Your Numbers Mean
Let's break down that sample prescription:
Right Eye (OD)
-2.50 -0.75 x 180
This means: "You are nearsighted with a sphere power of minus 2.50. You also have astigmatism with a cylinder power of minus 0.75. The astigmatism is oriented along the 180 degree axis."
Left Eye (OS)
-2.25 -0.50 x 175
This means: "You are nearsighted with a sphere power of minus 2.25. You have mild astigmatism with a cylinder power of minus 0.50. The astigmatism is oriented along the 175 degree axis."
Why Your Eyes Are Different
Notice that the right and left eye prescriptions in the example are different. This is completely normal. Most people have different prescriptions in each eye. Your left eye may need more or less correction than your right eye, or the astigmatism may be different in each eye. That is why Dr. Ngoddy tests each eye separately and provides an individual prescription for each eye.
What You Should Know About Your Prescription
Your Prescription Has an Expiration Date
Eye prescriptions are typically valid for one to two years. After that, you need a new exam to update your prescription. Your vision can change over time, and a current prescription ensures you have the best possible vision.
Glasses and Contacts Prescriptions Are Different
Your glasses prescription is not the same as your contact lens prescription. Contact lenses sit directly on your eye, while glasses sit slightly away from your eye. This small difference requires different power calculations. You need a separate contact lens prescription from Dr. Ngoddy.
You Can Share Your Prescription With Anyone
By law, your eye prescription belongs to you. After your exam, Dr. Ngoddy must provide you with a copy of your prescription.
Questions About Your Prescription
If you do not understand something about your prescription, call EyeServe and ask. Dr. Ngoddy is happy to explain your prescription in detail so you understand your vision needs.
Understand Your Prescription Better
Call: (404) 460-6163
Location: 844 Cleveland Ave SW, East Point, GA 30344
Sample Eye Prescription
Here is what a typical eye prescription looks like:
OD (Right Eye)
Value
Sphere (SPH)
-2.50
Cylinder (CYL)
-0.75
Axis
180
Add
+2.00
OD (Right Eye)
Value
Sphere (SPH)
-2.50
Cylinder (CYL)
-0.50
Axis
175
Add
+2.00
Understanding Each Part of Your Prescription
OD and OS
OD stands for "Oculus Dexter" which means right eye
OS stands for "Oculus Sinister" which means left eye
You may also see "OU" which means both eyes
Sphere (SPH)
The sphere is the basic lens power needed to correct your vision. This number corrects either nearsightedness or farsightedness.
Negative numbers (like -2.50) mean you are nearsighted. You have trouble seeing things far away, but see clearly up close.
Positive numbers (like +2.50) mean you are farsighted. You have trouble seeing things up close, but see clearly far away.
Zero or no number means you do not need correction for nearsightedness or farsightedness.
Cylinder (CYL)
The cylinder value corrects astigmatism, which is an irregularity in the shape of your cornea that causes blurred vision at all distances.
If there is no cylinder value listed on your prescription, you do not have astigmatism.
If there is a cylinder value, the number is always negative and is usually smaller in magnitude than your sphere number.
Axis
The axis is a number from 1 to 180 that indicates the direction of astigmatism in your eye. Think of it like the hand on a clock showing the angle of the astigmatism.
You will only see an axis number if you have astigmatism. If you do not have astigmatism (no cylinder value), there is no axis.
Add Power
The "Add" is additional power used in bifocals, trifocals, or progressive lenses for reading or other close work. It is typically a positive number like +1.50 or +2.00.
You will only see an Add if you need correction for presbyopia, which is difficulty focusing on close objects (usually after age 40).
What Your Numbers Mean
Let's break down that sample prescription:
Right Eye (OD)
-2.50 -0.75 x 180
This means: "You are nearsighted with a sphere power of minus 2.50. You also have astigmatism with a cylinder power of minus 0.75. The astigmatism is oriented along the 180 degree axis."
Left Eye (OS)
-2.25 -0.50 x 175
This means: "You are nearsighted with a sphere power of minus 2.25. You have mild astigmatism with a cylinder power of minus 0.50. The astigmatism is oriented along the 175 degree axis."
Why Your Eyes Are Different
Notice that the right and left eye prescriptions in the example are different. This is completely normal. Most people have different prescriptions in each eye. Your left eye may need more or less correction than your right eye, or the astigmatism may be different in each eye. That is why Dr. Ngoddy tests each eye separately and provides an individual prescription for each eye.
What You Should Know About Your Prescription
Your Prescription Has an Expiration Date
Eye prescriptions are typically valid for one to two years. After that, you need a new exam to update your prescription. Your vision can change over time, and a current prescription ensures you have the best possible vision.
Glasses and Contacts Prescriptions Are Different
Your glasses prescription is not the same as your contact lens prescription. Contact lenses sit directly on your eye, while glasses sit slightly away from your eye. This small difference requires different power calculations. You need a separate contact lens prescription from Dr. Ngoddy.
You Can Share Your Prescription With Anyone
By law, your eye prescription belongs to you. After your exam, Dr. Ngoddy must provide you with a copy of your prescription.
Questions About Your Prescription
If you do not understand something about your prescription, call EyeServe and ask. Dr. Ngoddy is happy to explain your prescription in detail so you understand your vision needs.
Understand Your Prescription Better
Call: (404) 460-6163
Location: 844 Cleveland Ave SW, East Point, GA 30344