How Bad Is My Eye Prescription?

A positive number on an eye prescription indicates that the prescription is correcting farsightedness, whereas a negative number indicates that the prescription is correcting shortsightedness. A higher number suggests a stronger prescription.

Since the numbers and symbols on an eye prescription are often difficult to understand, many people wonder how bad their eye prescription is.

According to research conducted by the Vision Council, approximately three out of four Americans require corrective lenses. However, many people do not understand what their prescription means.

The purpose of this article is to explain how to read an eye prescription and what the numbers indicate.

How to read an eye prescription

Each eye may require a different prescription.

Here are some tips to help people read their eye prescriptions:

• Identify a +: Positive numbers, such as +1.00, imply how strong a lens will have to be to correct farsightedness. Farsightedness is the inability to see objects that are located close to one’s eyes.

• Identify a – sign: Negative numbers, such as -1.00, indicate the lens strength needed to correct shortsightedness. Shortsightedness is when a person can see close things but distant objects appear blurry.

• A large number: Whether a + or -, a large number indicates a stronger prescription.

• OD and OS: The terms Oculus Sinister (left eye) and Oculus Dexter (right eye) refer to the left eye and right eye, respectively, on an eyeglass prescription.

• Eye differences: It is common for people to have different qualities of vision in their left and right eyes, particularly those with astigmatism.

• SPH: Spherical correction (SPH) refers to the amount of lens strength needed to correct vision that affects the whole eye. This number is usually listed first on the prescription.

• Cylindrical correction (CYL): Cylindrical correction is the second number and is only on prescriptions for people with astigmatism.

• ADD: Some people require a different prescription to magnify objects that are close to them. ADD refers to the strength that a vision care professional should add to a prescription when magnifying items close to them.

• AXIS: The axis notation indicates where the astigmatism correction should be placed in a lens.

• PRISM: An eye doctor can use a prism to help correct problems with how the eyes work together, such as an eye that tilts inward and the other looking straight ahead.

It is recommended that a person with any questions regarding the meaning of their prescription speak to their optician. They are able to answer any questions and explain the numbers to them.

What causes my prescription to change?

It is important to note that eyeglass prescriptions are subject to change as people’s eyes change. Usually, these changes are not caused by illness or injury. For example, children don’t fully develop the ability to focus both eyes at the same time until they have reached the age of seven.

As children grow, their eyes continue to change rapidly, and children with glasses should be examined by an eye doctor annually to ensure that their eyeglass prescription continues to meet their needs.

In addition to children, adults also undergo changes in their eyes, although at a slower pace.

It is important to note, however, that not all older adults will experience eye problems, but several eye conditions have been linked to aging, including:

• Cataracts: The National Institutes of Health (NIH) expects over 50% of people in America to develop cataracts by age 75.

• Glaucoma: If left untreated, glaucoma can cause vision loss and blindness.

• Age-related macular degeneration: According to the NIH, this is the leading cause of blindness in people over 65.

Presbyopia is the most common change caused by aging. Presbyopia develops as the lens of the eye becomes less flexible and stiffer as it ages. People can begin to experience the condition as early as their 20s.

Age causes the muscles that control pupil size to weaken, which makes it more difficult for the eyes to adjust to changes in light conditions.

A person’s pupils generally shrink in low light conditions, such as while driving at night, which makes it more difficult for them to see clearly.

Vision protection and improvement

National Eye Institute Trusted Source provides the following recommendations for protecting and improving vision:

• An eye exam with dilated pupils

• Maintaining a healthy lifestyle, which includes physical activity, a varied diet, and not smoking

• Take breaks from computer screens and wear sunglasses and protective eyewear when necessary in order to protect the eyes

61 million Americans are believed to be at high risk for vision loss, but only half have seen an eye doctor in the past year, according to the Centers for Disease Control and Prevention (CDC).

A regular, thorough eye examination plays a crucial role in maintaining and improving vision because it allows the physician to detect problems with the eyes at an early stage. According to the American Academy of Ophthalmology, a complete eye exam should include the following aspects:

• A thorough examination of the eyes is possible by dilating the pupils

• Reviewing the medical history

• Examination of the health of pupils

• Assessing visual acuity in order to determine an individualized prescription

• Testing the peripheral vision

• Conducting a tonometry test on the eyes

• Examining the retina and optic nerve

• The study of eye movement, also known as ocular motility, as well as the alignment of the eyes and the health of the eye muscles

• Performing a visual examination of the lens, cornea, iris, and eyelids

It is especially important for people with the following conditions to take care of their eyes:

• Diabetes – damage to the retina caused by high blood sugar is one of the most preventable causes of vision loss

• High blood pressure

• An eye disease history in the family

Medical professionals should be consulted if anyone notices changes in their vision in order to ensure early diagnosis and treatment.

In summary

By using the above guide, anyone who is uncertain about how bad their eye prescription is can interpret the numbers and notes on their prescription.

Medical professionals, such as opticians, can provide additional information or assistance to those who wish to know more.

As people age, their vision is likely to change, resulting in changes in prescriptions. It is important to maintain good general health and have regular eye examinations to protect their vision.