For many patients, the eye prescription slip received after an eye exam looks confusing and intimidating. Filled with numbers, abbreviations, and plus or minus signs, it often raises more questions than answers. Understanding your vision prescription helps you make informed decisions about glasses, contact lenses, and your overall eye care.

An eye prescription primarily measures how well your eyes focus light. The most common terms you’ll see are SPH (sphere), CYL (cylinder), and AXIS. SPH indicates the degree of nearsightedness or farsightedness. A minus sign means you are nearsighted and have difficulty seeing distant objects clearly, while a plus sign indicates farsightedness, where near objects may appear blurry. The higher the number, the stronger the correction required.

CYL and AXIS are related to astigmatism, a condition where the eye’s surface is slightly irregular,causing blurred or distorted vision at all distances. CYL shows the amount of astigmatism correction needed, while AXIS indicates the direction of that correction. These values work together and are essential for accurate lens design.

Another common value on your prescription is ADD, which is usually seen in people over the age of 40. This refers to presbyopia, a natural age-related change where near vision becomes more difficult. The ADD value helps in prescribing reading glasses or progressive lenses. You may also see PD, or pupillary distance, which measures the distance between the centers of your pupils and ensures proper lens alignment.

It’s important to understand that your prescription is not permanent. Vision can change due to age, health conditions, lifestyle, or screen habits. Wearing an outdated prescription can cause eye strain, headaches, fatigue, and reduced visual clarity. This is why regular eye check-ups are essential even if you feel your vision hasn’t changed.

Knowing how to read your eye prescription helps you become an active participant in your eye care journey. When you understand what those numbers mean, you can make better choices andensure your eyes receive the care they truly need.