Do you want to know if your vision is any good? Then, you need to read on. Have you recently gotten an eye exam and were told that you have a 20/20 vision. Could this possibly mean that you have perfect eyesight? And can you achieve even better eyesight? What is perfect vision? In order to find out if your vision is any good, you need to first understand the terminology related to vision and how the quality of vision is measured by eye doctors.
What Is The Difference Between Vision, Eyesight, And Acuity?
As the Visionary Eye Centre points out, the term visual acuity is used to describe the sharpness of vision. It helps measure the ability of a person to identify numbers or letters from a specific distance on the standardized eye chart. To determine visual acuity, one eye is tested at a time using the standardized eye chart. Since visual acuity is actually a static measurement, you have to sit still during the test as the numbers or letters being viewed need to be stationary. It is also possible to test visual acuity under high contrast conditions. Keep in mind that even though visual acuity testing might be useful for determining the relative clarity of one’s eyesight under standardized conditions, it does not predict the quality of vision under all situations. The following are some of the situations wherein visual acuity testing would not be as effective.
- Moving objects
- Colored Objects
- And objects which are similar to the background brightness
Visual acuity is determined according to three major neurological and psychological factors. These are mentioned below.
- How accurately the lens and cornea of your eye are able to focus light onto your retina.
- The vision centers in your brain and the sensitivity of the nerves in your retina.
- The brain’s ability to effectively interpret the information that has been received from your eyes.
Visual acuity measurement is influenced by the light which is focused on the highly sensitive and small portion of your central retina which is known as the macula during the eye exam.
The definition of eyesight is not as easy to explain. It depends on the dictionary or resource one refers to. Some of the resources describe it as the ability to see, vision, the sense to see, viewing, or range of sight. Moreover, the terms visual acuity and eyesight are often used interchangeably.
Vision is in fact a much broader term as compared to eyesight or visual acuity. The term vision includes a wide range of visual skills and abilities in addition to the ability to see or the sharpness of sight. It includes contrast sensitivity which is the ability to effectively track objects that are moving with accurate and smooth eye movements, depth perception, accuracy, color vision, and focusing speed etc.
For an accurate vision, the term 20/20 vision is commonly used. However, the term 20/20 visual acuity should be used instead to be realistic.
So What Is A 20/20 Vision?
The term 20/20 is commonly used and it refers to the visual acuity measures (20/60, or 20/40).The measurement system was developed by the Dutch ophthalmologist Herman Snellen in the year 1962 and the measurements are referred to as Snellen fractions.
The top number according to the Snellen visual acuity system of the Snellen fraction is in fact the viewing distance between the eye chart and the patient. In some countries the distance is normally 6 meters, whereas, in the United States, it is 20 feet. It is at this testing distance that the size of the alphabets on the smaller lines at the bottom of the eye chart can be considered normal as per visual acuity. It is known as the 20/20 line. If you are able to identify the letters that are located on this line but not lower, then you would have 20/20 or normal visual acuity. When it comes to the majority of Snellen charts, the smallest alphabets are known to correspond to visual acuity of 20/10. Anyone that has a 20/10 visual acuity is considered to have eyesight which is twice as sharp as someone who has a normal vision.
Can You See Better Than 20/20?
It is indeed possible to acquire a sharper vision than the normal 20/20 vision. The truth is that many healthy and young eyes are able to identify some of the alphabets that appear on the 20/15 line or for even smaller letters. In order to achieve a better than 20/20 vision, you need to check out this doctor. The eye doctor or the assistant would use an instrument to help show you the possible lenses for sharper eyesight. It is also due to the better printing methods that are used today as compared to during the time of Snellen. Thus, today the normal visual acuity is actually the ability to be able to identify alphabets that are in fact smaller than the traditional 20/20 line of the Snellen eye chart. Besides, people tend to live longer today as compared to during the time of Snellen. Aging might require one to opt for cataracts for larger letters and a normal vision during the post-60s.
If you feel that your 20/20 vision is not sharp enough, it is possible that your eyes have a higher-order aberration which cannot be corrected using soft contact lenses or regular eyeglasses. Wave front technology is used by eye doctors to determine the aberrations. It is possible for HOAs to be caused by slight irregularities in the shape of your eyes’ front surface. It is possible to get fitted with GP lenses (gas permeable contact lenses) to improve visual acuity as compared to soft contact lenses or eyeglasses. The reason for better improvement from GP lenses is because they tend to be rigid and are made to replace the irregular front surface of your eyes to provide a perfectly curved, smooth surface in order to ensure that light is focused much more accurately.