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.
Simply put, 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.
Blindness is also defined as visual acuity of less than 3/60, or corresponding visual field loss to less than 10 degrees, in the better eye with best possible correction.
What is legal blindness? A person is considered legally blind if they cannot see at six metres what someone with normal vision can see at 60 metres or if their field of vision is less than 20 degrees in diameter.
In general, the further away from zero the number on your prescription, the worse your eyesight and the more vision correction (stronger prescription) you need. A “plus” (+) sign in front of the number means you are farsighted, and a “minus” (-) sign means you are nearsighted.
20/30 to 20/60 is considered mild vision loss, or near-normal vision. 20/70 to 20/160 is considered moderate visual impairment, or moderate low vision. 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.
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.
A measurement of -6 is certainly not nothing and will require corrective lenses. It is, however, far from being blind and can be corrected by wearing glasses or contact lenses.
Legal blindness is defined as 20/200 vision. The prescription equivalent is -2.5. It is important to note that prescriptions for corrective lenses are different for each person, and measurements can be different for each eye.
Is minus 13 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.
If your number is between -0.25 and -2.00, you have mild nearsightedness. If your number is between -2.25 and -5.00, you have moderate nearsightedness. If your number is lower than -5.00, you have high nearsightedness.
A minus sign before the number indicates that you are nearsighted, while a plus sign means that you're farsighted. Lens power is measured in diopters. The higher the number, the stronger the prescription. For example, “-5.00” written under sphere means that you are very nearsighted and need a five diopter correction.
Once myopia exceeds 1,500 degrees, the eyeball becomes very abnormally elongated and the retina and vitreous tissues are stretched to their limits. At these magnitudes of severity, the eye will very likely suffer from one or more of the commonly associated eye diseases.
Moderate myopia has values of diopters from -3.00 to -6.00D. Usually, wearing the correct prescription glasses or contact lenses will mean your vision is fully functional. High myopia is usually myopia over -6.00D. In most cases, without glasses or contact lenses you will be legally blind.
What are the highest and lowest-strength reading glasses available? The lowest-strength reading glasses have powers of +0.25 diopters, whereas high-strength ones can go well beyond +2.50 diopters—in rare cases, all the way up to +4.00.
Legally Blind refers to people that have less than 20/200 vision in the better eye or a limited field of vision that is 20 degrees or less at its widest point.
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.
A negative number in either spot suggests that you are nearsighted, while a positive number shows that you are farsighted. The more negative (or positive) the number is, the more serious a refractive error you have. Contact lens prescriptions have OD and OS on them as well, but they include two other abbreviations.
The former represents correction for nearsightedness (difficulty seeing far away) and the latter represents correction for farsightedness (difficulty seeing close by). So, a prescription could be -3.75 meaning that the lens needs to provide three and three-quarter diopters of correction for nearsightedness.
Negative Numbers: If you see a minus sign in front of a number, that indicates nearsightedness, or myopia. Someone with -3 diopters of nearsightedness, for example, might have trouble reading words on a chalkboard from far away.
Someone is legally blind if their better eye — while wearing any glasses or contacts — has a visual acuity of 20/200 or less or a field of vision of less than 20 degrees.
The maximum negative eye power is typically around -20 diopters. This means that if you have myopia of -20 diopters, you will need to wear glasses or contact lenses with a power of -20 in order to see clearly.
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.
Last Updated Nov 27, 2022. People with nearsightedness struggle to see things far away from the face. For people with extreme nearsightedness, defined as a prescription of -6.0 diopters or more, it may be difficult to see anything more than a foot or so away from the face.