How to Read anEyeglasses Prescription

Pupillary Distance:

Your pupillary distance (PD) is the measurement between the centres of your pupils. This measurement is crucial for placing the optical centres of your lenses correctly.While often measured by an optician, in some cases, you might need to measure it yourself to ensure the best vision experience with your glasses.

Sphere (SPH):

The SPH denotes the power of your glasses. It can tell you if you're short-sighted (“-” negative sign before the power, difficulty seeing distant objects) or long-sighted (“+” positive sign before the power, difficulty seeing closer objects).

Cylinder (CYL):

The cylinder in your prescription refers to astigmatism, a common irregularity in the shape of the eye. It measures the degree of this irregularity. Think of your eyes as ideally spherical, like a basketball. However, many eyes are more like a rugby ball, slightly oval shaped. The cylinder value indicates how much this shape deviates from being perfectly round. A higher cylinder value suggests your eyes are more oval shaped, affecting your vision. If there s a 0 or nothing mentioned in this section, your eyes have a near perfect spherical shape.

Axis:

The axis complements the cylinder and denotes the orientation or angle of the irregularity caused by astigmatism. It s measured in degrees from 0 to 180 and specifies the exact location of this imperfection in your eyes. This helps the optician precisely correct your vision.

Prism:

The prism in your prescription corrects eye alignment issues, such as double vision due to eye misalignment. The prism power, direction (BU = base up; BD = base down; BI = base in; BO = base out), and strength help in aligning your eyes to eliminate visual disturbances.

Add:

The Add refers to additional power, mainly for reading, often associated with age related long sightedness (presbyopia). As we age, it becomes harder to focus on close up objects. This positive number represents the strength of additional power required for clear near vision.

Pupillary Distance:

Your pupillary distance (PD) is the measurement between the centres of your pupils. This measurement is crucial for placing the optical centres of your lenses correctly.While often measured by an optician, in some cases, you might need to measure it yourself to ensure the best vision experience with your glasses.