A person with 20/20 vision can see what the average person can see on an eye chart (optotype) when standing 20 feet away (20 feet = 6 meters).
HOW TO READ A PRESCRIPTION FOR GLASSES?
An eye chart (optotype) measures visual acuity. The top number is your distance in feet from the chart. The lowest number is the distance at which a person with normal vision can read the same line. For example, if you have 20/30 vision, it means that your vision is worse than average. Twenty feet away, you can read letters that most people can see from 30 feet away.
IS 20/20 VISION CONSIDERED PERFECT VISION?
20/20 vision is not perfect vision. A person may have 20/15 vision, which is sharper than average. If you have 20/15 vision, you can see a line in the eye chart (optotype) 20 feet away that the average person can only see when 15 feet away. The goal of glasses or contact lenses is to bring a person’s vision to 20/20.
Do not underestimate the big mistakes when ophthalmic examinations are not approached professionally. Ask yourself how many times you have witnessed someone close to you complaining about the incorrect diopter reading and that new glasses or contact lenses give him a constant headache. Of course, you should always take a period of adaptation of your eyes to glasses or contact lenses, but this should never last too long and may indicate a wrongly read result or even worse – an insufficiently well-conducted ophthalmological examination. That is why it is extremely important that your ophthalmological examination is always conducted by a specialist ophthalmologist.
Only about 35% of all adults have 20/20 vision without glasses, contact lenses, or eye surgery. With correction, about 75% of adults have 20/20 vision. In most states, you need vision of 20/40 or better to get a driver’s license.
WHEN SHOULD I OR MY CHILD HAVE AN EYE EXAM?
At the age of four, it is recommended that you test your child’s eyesight. Adults, when you reach middle age, you may lose your near vision. The lenses of your eyes become less able to bend. It becomes more difficult to change focus from distant to closer objects. This is called presbyopia . You may need reading glasses or bifocals to correct the problem.
Presbyopia is a condition where your eyes gradually lose the ability to see things clearly up close. It’s a normal part of aging. In fact, the term “presbyopia” comes from the Greek word meaning “old eye”. You may start to notice presbyopia shortly after age 40. You’ll probably find yourself holding your reading materials further away so you can see them clearly.
WHAT CAUSES PRESBYOPIA?
Your clear lens is inside the eye behind the iris. It changes shape to focus light on the retina so you can see. When you’re young, the lens is soft and flexible, changing shape easily. This allows you to focus on objects near and far away. After the age of 40, the lens becomes harder. He can’t change shape that easily. This makes reading or other close-up tasks difficult.
There is no way to stop or reverse the normal aging process that causes presbyopia. However, presbyopia can be corrected with glasses, contact lenses or surgery. People who have problems with near and distance vision can benefit from progressive lenses. If you do not take care of your presbyopia and if you neglect it, you can suffer from headaches and eye strain.
A HEALTHY EYE, HEALTHY VISION
A healthy eye contains a clear, smooth dome called the cornea. The cornea is a transparent “window” that allows light rays to pass unhindered and focus sharply on the retina.
If the cornea is not as smooth, clear, or round as it should be, or if the eyeball is too long or too short, light rays will bend (or refract) at unusual angles. This leads to blurred or distorted vision. The inability to achieve a sharp focus is called refractive error – it is the most common eye problem.
Refractive errors include nearsightedness (myopia), farsightedness (hyperopia) or astigmatism. Similarly, the eye will have trouble focusing if the naturally clear lens is clouded by cataracts, if it is not as flexible as it should be (presbyopia), or if there are other problems with the way the eye works. It is recommended that all adults have a basic eye exam by an ophthalmologist — a doctor who specializes in the diagnosis of eye diseases and conditions and the medical and surgical treatment of those conditions — by age 40, when early signs of disease appear and vision changes may begin to occur.
If you have an eye disease or risk factor, such as diabetes, high blood pressure, or a family history of eye disease, you should see an eye doctor even if you are under 40.
Adults over the age of 65 should have a comprehensive eye exam every one to two years or as recommended by an ophthalmologist. Some older people may need more frequent eye exams if they have a disease or condition that can affect their eye health.
When ophthalmologists notice something unusual during your exam, they may refer you back to your primary care physician or specialist for further examination and testing. Do not forget that the eye examination is extremely important, because it can also signal other diseases, which you can prevent or at least start treating in time with regular ophthalmological examinations.
Prevention is half of health and don’t make it difficult for you to take time for your health, a longer and better quality life. An eye examination is a relatively simple and pleasant procedure and should not take more than 45 to 90 minutes.