How to read your eyeglass prescription?

How to read your eyeglass prescription?

eyeglass prescription

What is an eyeglass prescription?

A glasses prescription is a detailed and professional document provided by an optometrist, outlining the specific requirements for your eyeglasses. It contains precise measurements indicating the necessary lens strength to correct your vision. This prescription is essential for addressing various visual impairments, including myopia (nearsightedness), hyperopia (farsightedness), and astigmatism. It serves as a crucial guide for opticians to create lenses that enhance your vision to optimal clarity, effectively transforming your visual experience to the highest definition.

Types of eyeglass prescriptions

Glasses prescriptions are highly individualized and vary significantly based on the specific visual requirements of each person. They are tailored to address diverse types of refractive errors, such as myopia, hyperopia, astigmatism, and presbyopia. Each prescription is meticulously calculated to provide the optimal level of correction for the wearer’s vision, ensuring precise and effective enhancement of eyesight.

(1). Myopia Prescriptions

If distant objects appear blurry while close-up reading remains clear, this indicates myopia or nearsightedness. In such cases, the prescription typically features a minus (-) sign, denoting the lens power required to correct this condition and bring distant objects into sharp focus.

(2). Prescription for farsightedness

If you have clarity in viewing distant objects, such as a plane in the sky, but face difficulty in reading small print, this condition is indicative of hyperopia, or farsightedness. In this scenario, your prescription will include a plus (+) sign, indicating the lens power necessary to correct your vision for close-up tasks.

(3). Astigmatism prescription

If your vision is distorted, with objects appearing wavy or unclear, this is likely due to astigmatism. In such cases, the prescription will include cylinder (CYL) and axis values. These measurements are crucial for customizing the lenses precisely, ensuring they correct the astigmatism and enhance the clarity of your vision.

(4). Bifocal and progressive prescriptions (multifocal)

Multifocal prescriptions function similarly to DJ mixing tracks, as they seamlessly combine different lens strengths for near and distant vision. This allows for a comprehensive range of vision correction, accommodating activities from close-up reading to recognizing distant street signs.

(5). Prescriptions with prismatic correction

A prism prescription is designed to correct alignment issues in your eyes. It functions as a corrective measure, ensuring both eyes coordinate effectively and efficiently. This specialized prescription addresses binocular vision discrepancies, facilitating improved and harmonious visual function.

What do all those letters and numbers mean?

Your eyeglass prescription contains specific numerical values that dictate the precise cutting of your lenses to suit your vision requirements. It is crucial to regularly update this prescription to ensure these values accurately represent your current visual needs. Commonly, the prescription includes a series of abbreviations and terms such as SPH, CYL, Axis, Prism, PD, among others, each signifying key aspects of your vision correction needs. Understanding these terms is essential for comprehending the details of your prescription.

(1). What do OD and OS mean?

OD (Oculus Dexter) and OS (Oculus Sinister) are critical terms in your eyeglass prescription, indicating the specifications for your right and left eye, respectively. OD refers to the right eye, while OS denotes the left eye. These terms are integral to ensuring that each lens in your eyeglasses is correctly customized to meet the individual visual needs of each eye. When reviewing your prescription, OD and OS act as clear indicators for the lens requirements of each eye, aiming to provide the precise vision correction required for each side.

(2). What does Ax (Axis) in the prescription mean?

The ‘Axis,’ often abbreviated as ‘Ax’ in your eyeglass prescription, plays a crucial role for individuals with astigmatism. This parameter, ranging from 0 to 180 degrees, specifies the precise orientation at which the lens must correct the irregular curvature characteristic of astigmatism. It directs the lens to focus on the specific angle necessary to rectify blurred or distorted vision. Essentially, the axis acts as a navigational tool for the lens, ensuring it accurately targets and corrects the astigmatic area for optimal visual clarity.

(3). What does PD (Pupillary Distance) in the prescription mean?

Pupillary Distance (PD) is a key measurement in eyeglass prescriptions, indicating the distance between the centers of your pupils. This measurement is critical as it ensures the lenses are accurately centered in your frames. Proper alignment of lenses according to your PD is essential for achieving optimal visual clarity and comfort. PD serves as a guide for precisely positioning the lenses, thereby guaranteeing you are looking through the most effective part of the lenses for the best possible vision.

(4). What does the CYL in the prescription mean?

In an eyeglass prescription, CYL (Cylinder) is a crucial parameter for individuals with astigmatism. It specifies the amount of lens power required to correct the visual distortions or blurriness characteristic of astigmatism. The CYL value acts as a corrective factor, fine-tuning the lens to precisely counteract the irregular curvature of the eye’s surface. This correction ensures that lines and images are perceived sharply and clearly. Essentially, the CYL figure represents the additional corrective strength needed in the lenses to effectively address the unique challenges posed by astigmatism.

(5). What does SPH (spherical) in your glasses prescription mean?

SPH, short for Sphere, in your eyeglass prescription, is a primary factor in correcting your overall vision. This value determines the necessary power of your lenses to ensure clear vision. A negative (-) sign accompanying the SPH value indicates correction for nearsightedness, helping to bring distant objects into clear focus. Conversely, a positive (+) sign is used for farsightedness, enhancing the clarity of objects that are near. In essence, SPH adjusts the lens power to optimize vision, whether for objects near or far, ensuring sharp and clear visual perception.

(6). What does ADD (add) mean in a prescription?

In multifocal eyeglass prescriptions, “ADD” stands for Addition. This value represents the extra lens power required for close-up activities, such as reading or intricate tasks like crafting. ADD is specifically designed to compensate for presbyopia, a common age-related decrease in near focusing ability. It is an additional power that supplements the primary prescription, ensuring clear vision for near tasks without the need to hold objects at an arm’s length or squint. Essentially, ADD serves as a crucial component in multifocal lenses, seamlessly bridging the gap between near and distant vision, maintaining clarity across various distances.

(7). What is the meaning of prism in prescription?

A prism in an eyeglass prescription is a specialized correction for individuals whose eyes do not align correctly. This optical element adjusts the direction of light entering the eye, thereby aiding in the coordination of both eyes. Prisms are typically prescribed for conditions such as double vision or eye muscle imbalances. Their role is to ensure proper alignment of the eyes, promoting harmonious visual function. The use of a prism in lenses is integral in correcting visual misalignments, enabling a unified and clear perception of the world.

(8). What does VA in your glasses prescription stand for?

VA, standing for Visual Acuity in an eyeglass prescription, refers to the clarity or sharpness of your vision. It is a metric that assesses how well you can discern shapes and details at various distances. Typically evaluated using an eye chart, often recognized by the prominent “E” at the top, VA quantifies your visual performance. When VA appears on your prescription, it indicates the level of your visual acuity, such as 20/20 vision, which is considered optimal. It essentially serves as a measure of your eyesight’s effectiveness, gauged by an eye care professional.

Frequently asked questions about prescriptions

(1). What is the difference between SPH and CYL in a prescription?

In eyeglass prescriptions, SPH (Sphere) and CYL (Cylinder) have distinct roles. SPH refers to the overall lens power required to correct myopia (nearsightedness) or hyperopia (farsightedness), providing a general vision correction. In contrast, CYL addresses the specific issue of astigmatism, which is caused by an irregular curvature of the eye leading to blurred or distorted vision. While SPH provides a broad correction to enhance overall visual clarity, CYL offers precise adjustment to correct the unique visual distortions associated with astigmatism. Together, these elements work in tandem to ensure comprehensive clarity in your vision.

(2). What if I have PLANO/PL under SPH?

In an eyeglass prescription, the term “PLANO” or “PL” listed under the SPH (Sphere) section signifies that there is no correction required for either nearsightedness or farsightedness in that specific eye. PLANO, indicating zero power, implies that the eye’s ability to see distant objects is satisfactory. Therefore, if PLANO is noted in your prescription, it indicates that this aspect of your vision does not require correction. Any necessary adjustments for other vision issues, such as astigmatism, would be addressed by different sections of the prescription, notably the CYL (Cylinder) and Axis.

(3). What if I have SPHERE/SPH/S/DS under CYL?

When “SPHERE,” “SPH,” “S,” or “DS” is noted under the CYL (Cylinder) section of an eyeglass prescription, it indicates that no correction for astigmatism is necessary for that particular eye. These terms signify that the eye does not require the specific focusing power typically addressed by CYL corrections for astigmatism. In essence, this part of the prescription confirms that there are no astigmatism-related issues to correct. As a result, the lenses will be tailored to address other vision problems, as specified by the SPH (Sphere) value and other elements of the prescription.

(4). What if I have 2 ADD values?

When a glasses prescription includes two different ADD values, it indicates the need for varying levels of close-up vision correction for each eye. This is often observed in prescriptions for multifocal lenses, such as bifocals or progressive lenses. In these scenarios, each eye may require a specific level of magnification to efficiently perform near-vision tasks, such as reading or computer work. Consequently, the lenses are individually crafted, with each ADD value precisely adjusted to meet the distinct requirements of each eye. This customization ensures that the wearer achieves the best possible clarity and comfort for near-distance activities.

(5). How does a contact lens prescription differ from an eyeglass prescription?

A contact lens prescription differs from a glasses prescription in several key ways. While both prescriptions correct vision, a contact lens prescription includes additional measurements due to the fact that the eye is not in the correct position. A contact lens prescription differs from a glasses prescription in several key ways. While both prescriptions correct vision, a contact lens prescription includes additional measurements due to the lenses being placed directly on the eyes.

Base Curve (BC): This measures the curvature of the contact lens to ensure a proper fit on the eye’s surface.

Diameter (DIA): This indicates the overall size of the contact lens.

Lens Brand and Type: Specific brands and types of contacts are often prescribed based on the eye’s health and wearing pattern needs.

Additionally, the power in a contact lens prescription may slightly differ from glasses due to the distance from the eye (contacts sit directly on the eye, while glasses are positioned a bit away). Additionally, the power in a contact lens prescription may slightly differ from glasses due to the distance from the eye (contacts sit directly on the eye, while glasses are positioned a bit away).

(6). Can a glasses prescription be used to purchase contact lenses?

No, a glasses prescription cannot be directly used to purchase contact lenses. While both types of prescriptions address vision correction, they have different specifications and measurements. A contact lens prescription includes specific details like base curve and diameter, tailored to how the lens fits directly on your eye. A contact lens prescription includes specific details like base curve and diameter, tailored to how the lens fits directly on your eye. It’s essential to get a separate, specific fitting and prescription for contact lenses from your eye care professional.

Extra nuggets of info to your prescription that go beyond the basic numbers

Your eye care professional may include additional information in your prescription beyond the standard parameters, such as specific lens recommendations to optimize your visual health.

Multifocal Lenses: Designed to provide multiple focusing powers, these lenses facilitate clear vision at different distances. Bifocals and trifocals feature separate areas for near and distant viewing.

Progressive Lenses: These lenses offer a seamless transition across different vision zones, accommodating near, intermediate, and distant sight without visible lines.

Anti-Reflective Coating: Applied to lenses, this coating minimizes glare from artificial light sources, enhancing vision clarity and reducing eye strain.

Photochromic Lenses: These adaptive lenses remain clear indoors and automatically darken when exposed to UV light outdoors, providing versatile vision correction.

Pupillary Distance (PD): This measurement, sometimes included in your prescription, is essential for aligning the lenses precisely with your eyes to ensure optimal vision.

Best place to buy eyeglasses

Warby Parker has stylish, high-quality frames at affordable prices.

Liingo Eyewear is another great option to buy glasses online.

EyeBuyDirect has a wide variety of budget frames starting at $6.

Best place to buy

1-800 Contacts is our #1 recommendation to buy contacts online. 1-800 Contacts is the best place to buy contacts online.

glasses USA
GlassesUSA has a huge selection of contacts, glasses, & sunglasses.

How long does it take for my prescription glasses to be ready?

On our website, it is usually 3 days, for some complex prescription glasses it is 9 days!



Hello! I'm Leimeng, and I wear a couple of hats at Qingzi Optical. Not only do I craft the articles you see on our website, adding a touch of professionalism with each word, but I also lead the export sales team. This dual role keeps my days interesting and dynamic!

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