What Does My Eye Prescription Mean?
An eye prescription is a written order for corrective lenses. It is written by an optometrist, ophthalmologist, or optician.
An eye prescription includes:
- Patient’s name
- Date the prescription was issued
- Expiration date
- Specifications for vision correction
- Prescriber’s name, contact number, and signature
Decoding Your Eye Prescription
An eye prescription may include any of the following abbreviations:
- OD: oculus dexter (right eye)
- OS: oculus sinister (left eye)
- OU: oculus uterque (both eyes)
- SPH: the strength of magnification in the lenses
- CYL: cylindrical correction, or the amount of lens power needed to correct astigmatism
- AXIS: indicates the angle of astigmatism correction
- ADD: addition, used for bifocal and multifocal lenses
The numbers listed on the prescription refer to the prescribed focusing power.
Focusing power refers to the eye’s ability to focus on something at a given distance. Its unit of measurement is called a diopter.
A positive number (indicated by a ‘+’ sign) refers to farsightedness or hyperopia. A negative number (indicated by a ‘-’ sign) refers to nearsightedness or myopia.
On an eye prescription, 0.00 represents vision that doesn’t need correction. The numbers indicate the level of severity of your nearsightedness or farsightedness. The further away from zero (+ or -), the worse the eyesight.
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How Bad Is My Eye Prescription?
No eye prescription should be considered ‘bad.’ Different prescriptions refer to different levels of correction needed to restore normal vision.
The American Academy of Ophthalmology uses the following benchmarks to classify the severity of nearsightedness or farsightedness:
- Mild +/-0.25 to +/-2.00
- Moderate +/-2.25 to +/- 5.00
- Severe +/- 5.00
What Eye Prescription is Legally Blind?
The term "legally blind" actually comes from the government. The U.S. Social Security Administration (SSA) uses this term to determine who is eligible for certain disability benefits, tax exemptions, and low-vision training.
In the United States, a person has legal blindness if:
- Their vision with glasses or contacts is 20/200 or worse
- Their visual field is 20 degrees or less in the better-seeing eye11
This means that a legally blind person has to stand 20 feet away from an object to see it clearly. People with normal vision can stand 200 feet away from that same object and see it clearly.
A legally blind person's vision is at least 10 times worse than someone with normal vision.
Some legally blind people have visual acuity better than 20/200. However, their peripheral vision is poor.
People with normal vision have a lateral field view of almost 180 degrees. This means that they can see objects located directly to their left or right at the same time.
If your visual field is only 20 degrees, your peripheral vision is reduced drastically. This is often called tunnel vision.
What Causes Legal Blindness?
Many eye diseases can lead to legal blindness. The most common causes of blindness are:10
Cataracts
Cataracts cause clouding of the eye’s lenses. It is the leading cause of blindness worldwide.
Glaucoma
Glaucoma is a disease that damages the optic nerve. It can cause blindness.
Age-related macular degeneration (AMD)
AMD is a disease affecting the retina's macular region. It is a leading cause of blindness in adults over age 65.
Diabetic retinopathy
Diabetic retinopathy is a condition that can affect people with diabetes.
Is It Bad if My Prescription Changes?
You shouldn't worry about your eye prescription changing over time. Gradual changes to visual acuity are normal as the flexibility of the natural lens changes over time.
These changes can be caused by aging or other eye conditions, such as:
Astigmatism
Astigmatism is a refractive error, like farsightedness or nearsightedness. It causes blurry or distorted vision.
Astigmatism is indicated on a prescription as part of the cylindrical (CYL) correction. If there is no number under CYL, it means there is no astigmatism, or it is so slight that it doesn’t need correction.
Amblyopia
Amblyopia is also called a lazy eye. One or both eyes don’t develop properly during childhood, which affects the eyes’ ability to focus.
Presbyopia
Presbyopia is also called age-related farsightedness. The eyes gradually lose the ability to see objects up close. It typically develops in people over 40 years old.
Sudden vision changes may signify serious eye disease, which should be looked at immediately.
What is 20/20 Vision?
"Normal" vision is 20/20. Someone with 20/20 vision can stand 200 feet from an eye chart and see it as clearly as a legally blind person sees it from 20 feet.
In most states, drivers must have 20/40 vision or better for an unrestricted driver’s license. If you wear eyeglasses or contacts, your corrected vision must be at least 20/40.
The World Health Organization uses the following benchmarks to categorize visual impairment:
- Normal: 20/10-20/25
- Near Normal visual impairment: 20/30-20/60
- Moderate visual impairment: 20/70-20/160
- Severe visual impairment: 20/200-20/400, or 11-20 degrees on the visual field
- Profound visual impairment: 20/500-20/1000 visual acuity, or 6- 10 degrees on visual field
- Near-total visual impairment: Counting fingers, Hand motion, Light perception, or 5 degrees or less on visual field
- Total visual impairment: No light perception
Treatment for Bad Eyesight
Medical professionals recommend an eye exam every two years for adults ages 19 to 40 with vision problems. Adults older than 40 should get their eyes checked once a year.
Treatments for bad eyesight include:
Summary
Eye prescriptions change slowly over time. While there's no "bad" eye prescription, you can be "legally blind" when your prescription is 20/200 or worse. Different diseases can cause bad eyesight, some treatments can help improve your vision. There are many resources for blind people.
In this article
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FAQs
Is My Eye Prescription Bad? - What is Legal Blindness? ›
If your prescription is -2.5 or lower, this means that you are legally blind. Visual acuity of -2.5 is equivalent to 20/200 vision. Visual acuity of -3.0, for instance, means that you have 20/250 or 20/300 vision. From there, visual acuity of -4.0 means that you have 20/400 vision.
What prescription level is legally blind? ›While there's no "bad" eye prescription, you can be "legally blind" when your prescription is 20/200 or worse. Different diseases can cause bad eyesight, some treatments can help improve your vision.
What is a legally blind loss of vision? ›Legal blindness: This is when the central vision is 20/200 in your best-seeing eye even when corrected with glass or contact lenses. Having 20/200 vision means that you have to be 10x closer or an object has to be 10x larger in order to see compared to a person with 20/20 vision.
Is 20 500 legally blind? ›In the United States, any person with vision that cannot be corrected to better than 20/200 in the best eye, or who has 20 degrees or less of visual field remaining, is considered legally blind.
Is 20 100 legally blind? ›With visual acuity of 20/100, you aren't legally blind. However, you may be referred for a specialized low vision exam to identify what optical devices or other support systems could help you.
Is 9.5 prescription legally blind? ›Most health institutions and government agencies agree that if the vision in your best eye is 20/200 with correction, then you are legally blind.
Is minus 7 legally blind? ›The definition of legal blindness is 20/200 vision WITH correction. If you see better than 20/200 with your -7.00 on you are NOT legally blind. If you were -100.00 and could see better than 20/200 with your glasses you would not be legally blind either.
What is the difference between blindness and legally blind? ›Legally blind means a person has a corrected vision of 20/200 in their best-seeing eye. If visual aids such as glasses can correct a person's vision to 20/20, they are not considered legally blind. Totally blind refers to a complete loss of sight.
What are the 4 types of blindness? ›- Low vision. If you have permanently reduced vision but retain some amount of your sight, you have low vision. ...
- Total blindness. Total blindness describes people with eye disorders who have no light perception (NLP). ...
- Congenital blindness. ...
- Legally blind.
-3.00 diopters or less is mild. -3.00 to -6.00 diopters is moderate. -6.00 to -9.00 diopters is severe. -9.00 diopters or more is extreme.
Is 7.5 legally blind? ›
Visual acuity less than 20/200 is considered legally blind, but to actually fit the definition, the person must not be able to attain 20/200 vision even with prescription eyewear.
Is minus 15 legally blind? ›First: What does it mean to be "legally blind?" In most states, if you have distance visual acuity less than 20/200 that is not correctable with glasses/contact lenses, you are legally considered to be "severely visually handicapped" (which used to be called "legally blind").
What are the legally blind rules? ›We consider you to be blind if your vision can't be corrected to better than 20/200 in your better eye. We also consider you blind if your visual field is 20 degrees or less in your better eye for a period that lasted or is expected to last at least 12 months. The duration requirement does not apply for SSI payments.
Is 20 400 vision a disability? ›20/200 to 20/400 is considered severe visual impairment, or severe low vision. 20/500 to 20/1,000 is considered profound visual impairment, or profound low vision. Less than 20/1,000 is considered near-total visual impairment, or near total blindness.
Is 20 70 legally blind? ›"Partially sighted": the person has visual acuity between 20/70 and 20/200 with conventional prescription lenses. "Legally blind": the person has visual acuity no better than 20/200 with conventional correction and/or a restricted field of vision less than 20 degrees wide.
Is 20 80 vision legally blind? ›Does having 20/80 vision mean you are legally blind? No, not necessarily. If your vision is worse than 20/200 then you would be legally blind. But if your vision is between 20/80 and 20/200 and you can still see reasonably well, then you are considered to have low vision.
Is minus 11 eyesight bad? ›Mild: -0.50 to -3. Moderate: -3.25 to -5.00. High: -5.25 to -10. Extreme: greater than-10.
What is legally blind 6? ›Legal blindness is defined as someone with less than 6/60 vision.
Is minus 6 eyesight bad? ›A refractive error greater than -6 is when an optometrist might diagnose high myopia in a patient. Low myopia can have a refractive error as low as -0.25, while moderate myopia caps out at -5.75. If left untreated and with age, high myopia can progressively worsen to a greater degree of refractive error.
Is minus 9 eyesight legally blind? ›If you're legally blind, your vision is 20/200 or less in your better eye or your field of vision is less than 20 degrees. That means if an object is 200 feet away, you have to stand 20 feet from it in order to see it clearly. But a person with normal vision can stand 200 feet away and see that object perfectly.
Is minus 9 eyesight bad? ›
At values +0,25 to +3,0 diopters we speak about slight defect, values +3,25 to +6,0 diopters represent medium farsightedness, from +6,25 to +9,0 diopters we talk about high defect. Serious defect (from +9,25 up) comes with impaired vision, but not only in the near but also for further objects.
Is negative 5.75 legally blind? ›You are legally blind when your visual acuity drops below 20/200 even with best possible correction or if you have a visual field less than 20 degrees. You are not legally blind as long as you can see 20/200 with your glasses.
Does legally blind mean disabled? ›Many people wonder is blindness a disability? If your vision is 20/200, or legally blind, you may qualify for disability benefits. The Social Security Administration (SSA) considers “legal” or “statutory” blindness as a qualified disability.
What causes legally blindness? ›The four leading causes of legal blindness are eye disorders, namely Age-related Macular Degeneration, Cataracts, Diabetic Retinopathy, and Glaucoma.
How many legally blind are there? ›Gender. Of the 253 million people in the world who are visually impaired, 55% are women (139 million).
Are there levels to blindness? ›Mild – visual acuity worse than 6/12 to 6/18. Moderate – visual acuity worse than 6/18 to 6/60. Severe – visual acuity worse than 6/60 to 3/60. Blindness – visual acuity worse than 3/60.
What is low vision disability? ›Low vision is a vision problem that makes it hard to do everyday activities. It can't be fixed with glasses, contact lenses, or other standard treatments like medicine or surgery. You may have low vision if you can't see well enough to do things like: Read.
What's the worst eye disease? ›Cataract. Cataract is a clouding of the eye's lens and is the leading cause of blindness worldwide, and the leading cause of vision loss in the United States.
Is minus 8.5 legally blind? ›Having a prescription of -8.50D just means you are very short-sighted and as long as you can see around 20/20 with Spectacles or contact lens, you are not legally blind. If when wearing spectacles or contact lenses and the vision in one eye is 20/200 or worse then you would be legally blind.
How bad vision can LASIK fix? ›The average refractive prescription that qualifies for laser eye surgery is: Nearsighted ness up to -8.0 diopters. Astigmatism up to -3.0 diopters. Nearsightedness with astigmatism up to -9.0 diopters.
What's the highest eye prescription? ›
Typically, eye doctors will set their limits to +6 for farsightedness, -12 for nearsightedness, and 6 diopters for astigmatism. However, not all laser strengths are the same, so there's some wiggle room. Plus, someone with a -12 prescription might be approved for LASIK while someone with a -9 prescription isn't.
How blurry is legally blind? ›Legally blind refers to vision that is 20/200 or less in your better eye that cannot be corrected with standard glasses or contacts, or a visual field of 20 degrees or less.
Is minus 14 eyesight bad? ›A lens Rx for -14 Diopters tells us you have a very, very high degree of nearsightedness (myopia). This would be considered in the "severe" range. Of all the people who are myopic, less than 2% are worse than -10 Diopters.
How negative do you have to be to be legally blind? ›And to be deemed "legally blind," their vision must be bad enough that they meet one of two standards: They must have a visual acuity of 20/200 or less in the eye they can see out of best (while wearing corrective glasses or contacts) or have a visual field of no more than 20 degrees.
What is total blindness? ›Total blindness is a term used to describe those who have complete lack of light perception, documented as no light perception (NLP). Only about 15% of people with eye disorders have total blindness, the majority of those with visual impairment have some level of vision.
Is 20 180 legally blind? ›A person is considered to have low vision if their best-corrected visual acuity is 20/70 or less. If their best-corrected vision is 20/200 or less, they're considered legally blind.
Is minus 6 eyesight legally blind? ›Normal vision is 20/20. That means you can clearly see an object 20 feet away. If you're legally blind, your vision is 20/200 or less in your better eye or your field of vision is less than 20 degrees.
Is minus 10 eyesight bad? ›It is high myopia.
Is minus 12 legally blind? ›First: What does it mean to be "legally blind?" In most states, if you have distance visual acuity less than 20/200 that is not correctable with glasses/contact lenses, you are legally considered to be "severely visually handicapped" (which used to be called "legally blind").
Is minus 14 legally blind? ›What eye prescription strength would be classified as "legally blind"? You are legally blind when your visual acuity drops below 20/200 even with best possible correction or if you have a visual field less than 20 degrees.
How bad is minus 14 eyesight? ›
A lens Rx for -14 Diopters tells us you have a very, very high degree of nearsightedness (myopia). This would be considered in the "severe" range. Of all the people who are myopic, less than 2% are worse than -10 Diopters.
How bad can your eyes be for Lasik? ›LASIK is available to a variety of patients, but patients will generally qualify for treatment if their vision falls between -0.5 D to -8.0 D myopia. The maximum prescription for treatment for patients with moderate to severe myopia is around -8.0 D.
What is Category 4 blindness? ›Severe blindness – visual impairment category 4 in one eye and no visual impairment in the other eye.
What prescription is too low for LASIK? ›While it can vary, a typical Laser Eye Surgery clinic will qualify patients for LASIK treatment from -0.5 D to -8.0 D myopia. With a prescription of below 0.5 D, people only rarely require glasses, so LASIK is usually not recommended unless the patient also has some degree of astigmatism.
What myopia is too high for LASIK? ›Typically, eye doctors will set their limits to +6 for farsightedness, -12 for nearsightedness, and 6 diopters for astigmatism. However, not all laser strengths are the same, so there's some wiggle room.
Is negative 6 bad for eyes? ›A refractive error greater than -6 is when an optometrist might diagnose high myopia in a patient. Low myopia can have a refractive error as low as -0.25, while moderate myopia caps out at -5.75. If left untreated and with age, high myopia can progressively worsen to a greater degree of refractive error.