How To Read A PrescriptionWhen you are done with your eye exam and you are given a prescription, the next thing you think about is probably what kind of glasses to try out. But after looking closely at the prescription, you are unable to understand the language used.

At HiP Optical, we not only offer you superb eyeglasses and sunglasses but also help you to make sense of every number, abbreviation, and term used in your subscription. In doing so, we enable you to understand what the prescription discloses about your vision.

Whether you are a newbie or long-time eyeglass wearer, knowing how to read your prescription will help you to know the kind of glasses you need. In fact, if you will be ordering glasses online, you may be required to input your prescription on the order form. If you can’t read it, the ordering process will get complicated.

The ability to read your subscription gives you a better understanding of your vision problem and what it takes to correct it. Understanding your prescription will also help you to identify and avoid medical errors. The following guide helps you to know how to read a prescription. 

Doctor writing

Some people have found doctor writings hard to read. Others have termed doctors' way of writing as bad. In spite of that, doctors have over the years used their writing to communicate prescriptions for eyeglasses. Usually, eye doctors write prescriptions in a standard format so that they can be interpreted worldwide. 

Physicians use shorthand to communicate details about your vision correction. Historically, prescription writings have been based on Latin words and this happens to date. But why rely on Latin and it is not commonly spoken by many people?

Latin abbreviations

The main reason for using Latin abbreviations is that Latin is universally understood among medical professionals and it’s more concise when compared with other languages. In fact, the word 'prescription' is derived from a Latin word – praescriptus. The prefix 'pre' means before, and 'script' refers to writing.

This indicates that a prescription must be written before administering a drug or using other ways to address an identified problem. Whenever you are in doubt about the doctor's writing, it is always wise and advisable to seek clarification from your physician.

So what do the numbers, abbreviations, and terms on your prescription mean?

Learn how to read eye prescriptions

Eyeglass prescriptions include several elements of your vision that should be corrected. To learn how to read your prescription, you need to understand the meaning of different Latin abbreviations, terms, and numbers used. As you learn how to understand your prescription, you should keep several facts in mind. For instance, the more your prescription numbers deviate from zero, the more rectification is needed.

Additionally, a minus or plus sign that is written in front of eyewear prescription number is a shorthand for far or nearsightedness. Thus, a "+" sign means you are farsighted and thus you experience problems seeing things that are close up. On the other hand, a "-" sign is an indication that you are near-sighted. This means that you have trouble seeing things that are far away.   

Learning how to read a prescription is therefore very vital to the glass wearer. Sometimes there may be errors in printing your prescription. Other times, there may be omissions in the way the prescription is written. But you can overcome these problems by learning how to interpret your eyewear prescription.

Eyeglass prescription

Whenever your eye exam shows that lenses are necessary to correctly identify eye problems, the eye doctor will provide a prescription at the end of the examination. A prescription constitutes various elements that specify the value of every parameter that the eye doctor deems necessary for making corrective lenses. 

Although the elements may vary, they typically include the OS, OD, prism number, and more. The intention of creating an eye prescription is to define the ideal vision correction required to have and enjoy the best possible visual acuity regarding near vision as well as distance vision. So with an eye prescription, you can order new glasses that will help to correct your vision problem. A great step to making sense of your eyewear prescription is to understand the meaning of OS and OD. 

Oculus sinister (OS)

OS is used by eye doctors to refer to the left eye. So issues relating to the left eye will be found under the initials OS. This also applies to the correction required with regard to the left eye. So OS acts as a heading under which numbers and other abbreviations concerning the left eye are written.

Oculus Dexter (OD)

OD is the opposite of OS and represents the right eye. Thus the numbers that represent parameters specific to the right eye are written under OD. These include the visual deficiencies identified with the eye as well as the correction necessary to rectify the problem.

Oculus dexter and Oculus sinister are forms of traditional abbreviations that have been utilized for many years in the prescription for eye medicine, contact lenses, and glasses. However, modern medical professionals are departing from this tradition and are now replacing OD with RE and OS with LE.

If you are planning to order your prescription glasses online, look no further! Hip Optical offers an easy way to place your order. We don’t mind contacting your eye doctor for any clarification with regard to your specifications. 

Sphere (SPH)

The sphere specifies the lens power needed to correct your vision deficiency. The word sphere is derived from the lenses' geometry. A lens usually gets its power from curved surfaces. SPH is measured in diopters and it is prescribed to rectify farsightedness or nearsightedness. If there is a minus sign (-) under the SPH heading, then you have nearsightedness. On the other hand, you are farsighted if there is a plus (+).

Cylinder CYL 

CYL signifies the lens power needed to fix astigmatism. If there is no number under the cylinder, your eye doctor found little or no astigmatism that needed correction. The cylinder number may be preceded by a plus sign (farsighted astigmatism) or a minus sign (near-sighted astigmatism). 

Amount of prismatic power

The prismatic power that is required for your eyes is represented by the prism number. The prescription of the prismatic power is done to aid in resolving eye alignment problems, either horizontally or vertically. Although the amount of prismatic power is one of the elements that are included in eye prescriptions, it is uncommon. This is because the associated problem is rather rare and thus only a negligible number of individuals may have prescription power in their prescriptions.


The axis denotes the position of the eye astigmatism. This element defines the lens meridian with no cylinder power to rectify astigmatism. The axis is denoted with numbers that range from 1 to 180. Number 90 represents the vertical eye meridian while the horizontal meridian is noted by number 180. If your prescription has cylinder power, it will also have an axis value. This value comes after the cylinder power value and it’s led by an 'X'.


This is another aspect of prescription that refers to magnifying or additional power required to rectify presbyopia or the inability to see close up objects. This power increases as one’s eyes move down in the lens corridor with regard to multifocal lenses. Usually, the add number appears as a plus power. This is so even when it isn’t led by a plus sign on the prescription. Often, it is also the same number for both eye lenses.


The pupillary distance (PD) represents the distance between the centers of your eyes pupils. This distance changes particularly as children grow. But it stops changing after you reach adulthood. The PD is used to properly fit your lenses. It is also used to offer you optimum visual performance and comfort. 

At Hip Optical, we use facial-recognition software to determine your pupillary distance. This innovative method helps us to achieve extreme accuracy. So the next time you want to measure your PD and acquire new glasses, try Hip Optical and you will never regret your move.