Getting a new eyeglass prescription can be both exciting and a bit perplexing. The series of numbers and terms on that small piece of paper from your eye care professional might seem like a secret code. However, understanding your lens prescription is crucial for obtaining the right eyewear and ensuring optimal vision correction.

Decoding the Prescription

Your prescription typically consists of several components, including Sphere (Sph), Cylinder (Cyl), Axis, and sometimes, additional details for near or reading vision (Add). Here's a breakdown:

1. Sphere (Sph): This indicates the amount of lens power you need to correct nearsightedness or farsightedness. A negative number (-) is for nearsightedness, while a positive number (+) is for farsightedness.
2. Cylinder (Cyl) and Axis: These values address astigmatism, a condition where the eye has an irregular shape, causing blurry or distorted vision. The Cylinder represents the degree of astigmatism, and the Axis indicates the orientation of the astigmatism.
3. Presbyopia (Add): If you're over 40 and require assistance for reading or close-up work, you might see an additional prescription value for reading. This is called the "Add" power, and it indicates the additional magnifying power needed for near vision.

Understanding the Numbers

Let's consider an example: If your prescription reads -2.50 Sph, -1.00 Cyl, 180 Axis, and +2.00 Add, here's what each part means:

• -2.50 Sph: You're moderately nearsighted (myopic), and the negative sign indicates the concave lens needed to correct it.
• -1.00 Cyl: You have astigmatism, and the negative sign indicates the concave cylinder lens required. The -1.00 is the power needed for astigmatism correction.
• 180 Axis: The astigmatism is oriented along the horizontal axis, which is at 180 degrees.
• +2.00 Add: If you're over 40, this indicates that you need additional magnifying power for reading or other close-up activities.

Interpreting Prescriptions for Different Needs

Nearsighted (Myopia):

• Prescription Example: -3.75 Sph
• Explanation: You have difficulty seeing objects at a distance. The negative Sph value signifies a concave lens to correct nearsightedness.

Farsighted (Hypermetropia):

• Prescription Example: +2.25 Sph
• Explanation: You have difficulty seeing close-up. The positive Sph value indicates a convex lens to correct farsightedness.

Astigmatism:

• Prescription Example: -1.50 Cyl, 90 Axis
• Explanation: You have astigmatism, and the Cyl and Axis values determine the correction needed. A cylindrical lens is required, and the Axis denotes the orientation.

Presbyopia (Reading Glasses):‍

• Prescription Example: +1.50 Add
• Explanation: You need additional magnifying power for reading or close-up work.

Tips for Understanding Your Prescription

Power Sign:

• Negative (-): Nearsightedness.
• Positive (+): Farsightedness.

Cylinder and Axis for Astigmatism:

• Understand that these values work together to correct distorted vision caused by astigmatism.

Reading Addition (Add):

• This is relevant if you're over 40 and need assistance for reading.

OD (Right Eye) and OS (Left Eye):

• Your prescription might have values specified for each eye.

Conclusion

Understanding your lens prescription empowers you to make informed choices about your eyewear. If the numbers still seem like a puzzle, don't hesitate to ask your eye care professional for clarification. Remember, your prescription is unique to your eyes, and the right lenses can make a significant difference in your vision clarity and overall eye health.