Your Complete Guide to Eyeglass Lenses and Prescriptions

When shopping for eyeglasses, many people find themselves overwhelmed by the technical terms on their prescription. Numbers, abbreviations, and special lens options can look confusing at first glance. But once you understand what they mean, you’ll realize that each parameter is carefully designed to give you the clearest, most comfortable vision possible. In this guide, we’ll break down common prescription terms and explore different lens customization options to help you choose what’s best for your lifestyle.

Key Prescription Parameters

1. Sphere (SPH) – Nearsightedness or Farsightedness

The SPH value corrects overall vision clarity by compensating for either nearsightedness (myopia) or farsightedness (hyperopia).

• Minus (-): You are nearsighted and need help seeing things far away.
• Plus (+): You are farsighted and need help with near vision.

👉 Think of SPH as the foundation of your prescription — it adjusts the way light enters your eyes, ensuring sharper focus.

2. Cylinder (CYL) & Axis – Correcting Astigmatism

If you see CYL and Axis values on your prescription, it means your eye doctor has diagnosed you with astigmatism.

• Cylinder (CYL): Measures the degree of astigmatism — how much correction your eyes need.
• Axis: The angle (between 0° and 180°) indicating where the astigmatism occurs on your cornea.

👉 Together, CYL and Axis sharpen distorted or blurred vision.

3. ADD (Addition) – Near Vision Support

The ADD value appears in prescriptions for people who need help with close-up tasks, such as reading or working on a computer. This is common for people with presbyopia (age-related difficulty in seeing up close).

Typically listed as a positive number: Indicates the additional magnifying power required.

👉 If you’ve ever heard of progressive lenses or bifocals, the Add value is what makes them possible.

4. Pupillary Distance (PD) – Aligning Lenses with Your Eyes

PD is the distance between the centers of your pupils, measured in millimeters. Accurate PD ensures that the optical center of your lenses matches your eyes.

• Single PD: One measurement for both eyes.
• Dual PD: Separate measurements for the left and right eye (e.g., 32mm/31mm).

👉 Without the correct PD, even perfectly made lenses may feel uncomfortable or cause eye strain.

Lens Customization Options

Once your prescription is set, you can further enhance your glasses with different lens coatings and upgrades. These add comfort, durability, and protection to match your daily activities.

1. UV Protection Coating

Protects your eyes from harmful ultraviolet rays, reducing the risk of long-term eye conditions such as cataracts. This coating is especially useful if you spend time outdoors.

2. Blue Light Filter

Perfect for people who work on computers, use phones frequently, or spend hours in front of digital screens. It reduces eye strain, improves sleep quality, and helps protect your eyes from digital fatigue.

3. Anti-Reflective (AR) Coating

Minimizes glare from headlights, computer screens, and bright lighting. Ideal for night driving or anyone who wants clearer vision in bright conditions.

4. Scratch-Resistant Coating

Extends the life of your lenses by protecting them from everyday wear and tear.

5. Photochromic Lenses

Also known as “transition lenses,” these automatically darken in sunlight and return to clear indoors — giving you the convenience of sunglasses and eyeglasses in one.

Common Lens Materials

When choosing a new pair of glasses, the lens material is just as important. The right lenses not only affect how well you see, but also determine comfort, durability, and safety. Here’s a breakdown of the most common lens materials and their advantages.

1. Glass Lenses 

• Pros: Excellent optical clarity, scratch-resistant.
• Cons: Heavy, breakable, unsafe for children or active users.
• Best for: People who prioritize crystal-clear vision and don’t wear glasses for long hours.

2. Plastic Resin Lenses (CR-39)

• Pros: Lightweight, affordable, high optical quality.
• Cons: Easier to scratch compared to glass (needs protective coating).
• Best for: Everyday eyewear—this is the most commonly used lens material.

3. Polycarbonate Lenses 

• Pros: Impact-resistant, lightweight, thin. Provides built-in UV protection.
• Cons: More prone to scratches (anti-scratch coating recommended).
• Best for: Children, athletes, or anyone needing strong safety protection.

4. High-Index Lenses 

• Pros: Thinner and lighter than standard plastic lenses. Stylish and comfortable for high prescriptions.
• Cons: More expensive, may show slight color distortions at the edges.
• Best for: People with strong prescriptions who want thinner, more attractive lenses.

5. Trivex Lenses 

• Pros: Combines the lightness and safety of polycarbonate with sharper optical clarity. Strong, impact-resistant, and lightweight.
• Cons: Higher cost than standard resin or polycarbonate lenses.
• Best for: Those who want both excellent vision quality and safety.

Final Thoughts

Choosing the right lens customization is just as important as picking the right frame. From Sphere Power, Cylinder, and Axis corrections to specialized coatings and materials, every detail contributes to better vision and daily comfort.

At our store, we not only provide stylish AR Glasses but also offer customized lens services tailored to your exact prescription and lifestyle needs. If you’re unsure which type of lens or coating suits you best, our team is here to guide you step by step.