How to Read and Understand Your Glasses Prescription

Looking to buy prescription glasses online in the UK but unsure how to read your prescription? At 2020Glasses.co.uk, we make it easier than ever to find the perfect pair of glasses for your vision needs. Understanding your prescription is crucial for ensuring you get the right lenses for both comfort and clarity. This guide will explain how to read your glasses prescription and what all the numbers mean, so you can confidently shop for your next pair of prescription glasses.

What Information Is on Your Glasses Prescription?

When you visit an optometrist, they will provide you with a prescription that includes several measurements. These numbers help determine the ideal lenses for your eyes. Here’s a breakdown of the main components of a typical prescription and how to interpret them.

1. Sphere (SPH): The Strength of Your Prescription

The Sphere (SPH) value indicates whether you are nearsighted (myopic) or farsighted (hyperopic). It also tells you the strength of the prescription.

• Minus (-): If your SPH value is preceded by a minus sign, it means you are nearsighted. This means you have difficulty seeing objects in the distance.
• Plus (+): If your SPH value has a plus sign, it means you are farsighted, and you have difficulty seeing objects up close.

Example:

• SPH -2.50means you are nearsighted with a prescription of -2.50 diopters.
• SPH +1.75means you are farsighted with a prescription of +1.75 diopters.

2. Cylinder (CYL): Astigmatism

The Cylinder (CYL) value indicates the presence and strength of astigmatism, a condition where the cornea or lens is irregularly shaped, causing blurred or distorted vision. The cylinder number is always followed by either a plus (+) or minus (-) sign:

• A minus (-)sign means you have nearsighted astigmatism.
• A plus (+)sign indicates farsighted astigmatism.

Example:

• CYL -1.00means you have nearsighted astigmatism with a correction of -1.00 diopters.
• CYL +0.75means you have farsighted astigmatism with a correction of +0.75 diopters.

3. Axis: The Direction of Astigmatism

The Axis value refers to the orientation of the astigmatism. It’s measured in degrees from 1 to 180 and shows where the steepest part of the cornea or lens is. This is important for correcting the irregular shape of the eye.

Example:

• Axis 90°means the steepest part of your cornea is vertical.
• Axis 180°means the steepest part of your cornea is horizontal.

4. Add: Near Vision for Reading (Bifocal/Progressive Lenses)

The Add value is for those who need additional magnification for near vision tasks, like reading or using a smartphone. The Add value is used for bifocal or progressive lenses to help with close-up vision. It’s always positive (+) and is added to your SPH value for near-sightedness correction.

Example:

• Add +2.00means you need an additional 2.00 diopters for near vision.

5. Pupillary Distance (PD): Accurate Lens Alignment

The Pupillary Distance (PD) is the measurement between the centers of your pupils, typically measured in millimetres. This ensures that the lenses in your glasses are aligned properly in front of your eyes. Providing the correct PD is essential when buying prescription glasses online to ensure a comfortable fit.

Example:

• A typical PD ranges from 54mm to 68mmfor adults but can vary depending on facial features.

6. Prism: Correcting Eye Alignment Issues

The Prism value on your prescription is used if you have binocular vision problems or eye alignment issues. Prism correction helps prevent or reduce double vision (diplopia) by ensuring your eyes work together properly. It’s commonly prescribed for conditions such as strabismus (eye misalignment) or when the eyes have difficulty focusing on a single point.

• The Prismvalue is usually given in prisms diopters and is accompanied by a direction (Base), indicating the direction the prism should correct.

Example:

• Prism 1.50 BDmeans you have 1.50 prism diopters, and the base is downward (BD = Base Down).

7. Base: The Direction of Prism Correction

The Base value indicates the direction of the prism correction. It tells your optician how to align the prism in your lenses. The direction can be one of the following:

• Base Up (BU): Prism is directed upwards.
• Base Down (BD): Prism is directed downwards.
• Base In (BI): Prism is directed inwards, towards the nose.
• Base Out (BO): Prism is directed outwards, towards the temple.

Example:

• Prism 2.00 BOmeans you need 2.00 prism diopters with the base directed outward.

Understanding Your Prescription: A Sample Breakdown

Here’s an example of a full prescription with all the measurements we’ve discussed:

Right Eye (OD):

• SPH -2.50
• CYL -1.00
• Axis 90°
• Add +2.00
• Prism 1.50 BD
• Base Down (BD)

Left Eye (OS):

• SPH -2.00
• CYL -0.50
• Axis 80°
• Add +2.00
• Prism 1.00 BO
• Base Out (BO)

PD: 64mm

This means:

• You are nearsighted in both eyes.
• You have astigmatism in both eyes.
• You need additional magnification for close-up vision (reading glasses).
• Your PD is 64mm, ensuring proper lens alignment.
• You have prism correction to align your eyes properly, with the right eye requiring downward correction (BD) and the left eye needing outward correction (BO).

How to Use Your Prescription When Shopping for Glasses Online

When shopping for prescription glasses online at 2020Glasses.co.uk, ensure that you have the following details from your prescription:

1. SPH: The degree of nearsightedness or farsightedness and the strength of your prescription.
2. CYL and Axis: If you have astigmatism, and the orientation of the astigmatism.
3. Add: For near vision correction, especially for bifocals or progressive lenses.
4. PD: For proper lens alignment and comfort.
5. Prism and Base: If you have any binocular vision issues that require prism correction.

Make sure all the details are accurate, and you’ll have no trouble finding the perfect pair of prescription glasses at 2020Glasses.co.uk.

Key Tips When Ordering Prescription Glasses Online

• Double-Check Your Prescription: Ensure that the prescription is up-to-date and all measurements are correct.
• Enter Your PD: Always provide an accurate Pupillary Distance (PD) when ordering online.
• Choose the Right Frame: co.ukoffers a variety of stylish frames. Choose one that fits your prescription and complements your style.

Conclusion: Get the Best Prescription Glasses from 2020Glasses.co.uk

Understanding your glasses prescription is essential when buying prescription eyewear online. By knowing how to interpret your SPH, CYL, Axis, Add, Prism, Base, and PD measurements, you can confidently shop for glasses that will fit your needs. At 2020Glasses.co.uk, we are here to help you every step of the way. Browse our extensive collection of prescription glasses and choose from a variety of stylish frames to find your perfect match.

If you’re unsure about entering your prescription details online, don’t worry! You can always upload a photo or scan of your prescription, and one of our optical experts from 2020Glasses.co.uk will contact you directly to discuss your requirements and ensure you get the perfect lenses.

Need help with your prescription or choosing the right glasses? Our customer service team is always here to assist. Start shopping today at 2020Glasses.co.uk, and see the world clearly!