If you were told by your doctor that you have 20/20 vision after an eye exam, does this mean your eyesight is perfect? Is it probable to have a better vision than 20/20 vision? But, what is “perfect vision” anyway?
Let us take a closer look at terminologies related to vision for us to further understand how eye doctors measure vision.
The Difference Between Visual Acuity, Eyesight, and Vision
Visual acuity. This means the sharpness of your vision. The eye is measured one at a time using a standardized eye chart. This measures your capacity to distinguish letters or numbers on the Snellen eye chart from a specific viewing distance. Visual acuity is also tested under high contrast conditions such as black letters or numbers against a white background.
However, visual acuity is not predictive of your overall quality of vision especially with:
- colored objects
- dark conditions
- moving objects
Visual acuity is determined only by three major physical and neurological factors:
- The accuracy of the cornea and lens to focus light onto the retina
- The sensitivity of the retinal nerves and vision centers in the brain
- The capacity of the brain to decipher information as perceived by the eyes
Eyesight. The exact meaning of eyesight could be ambiguous. It may be defined as the ability to see, vision, range of sight, view, or the sense of seeing depending on which dictionary is used. Normally, “eyesight” and “visual acuity” can be used interchangeably.
Vision. This term is broader than visual acuity and eyesight. Vision usually includes a more extensive range of visual skills and abilities. These may include contrast sensitivity, the ability to follow moving objects with smooth and precise eye movements, color vision, focusing speed and accuracy, depth perception, and more.
Considering the more inclusive (and accurate) meaning of “vision” is used, what most of us say “20/20 vision” should actually be called “20/20 visual acuity.” However, the term “20/20 vision” is unlikely to be changed due to how common it became.
What Does 20/20 Vision Mean?
20/20 is a visual acuity measurement which is also called Snellen fractions, named after the eye measurement chart developed by Herman Snellen. In the Snellen visual acuity system, the uppermost number of the Snellen fraction is the actual viewing distance within the patient, and the eye chart. This is standardly 20 feet in most countries.
The letters on the chart are sized from large to small starting from the top. As the letters decrease in size per line, the visual acuity measurements get closer to 20/20. The corresponding lines with even smaller letters than the 20/20 line measures to a visual acuity better than 20/20.
The single biggest letter “E” at the uppermost part of the Snellen eye chart corresponds to 20/200 visual acuity. If this is the only letter you can read at 20 feet distance, you are already considered to be legally blind. The last line with the smallest letters, on the other hand, corresponds to 20/10 visual acuity which is twice as sharp as 20/20 vision.
Is It Possible to Have Better Vision Than 20/20?
Yes, it’s certainly possible to see better than 20/20 vision. In fact, people with young and healthy eyes can easily read at least some of the letters on the 20/15 line or even smaller letters on the Snellen chart.
However, despite having 20/20 vision, you may still feel like it is not sharp enough. This could be because your eyes have higher-order aberrations (HOA) which are more complex refractive errors such as poor night vision and seeing glares or halos. These cannot be easily corrected with regular glasses or contact lenses.
If HOAs are caused by deformities in your cornea, your doctor may prescribe a gas permeable contact lens (GP lenses) These are made of rigid material that temporarily corrects the shape of your cornea overnight to improve vision. Custom wavefront LASIK is another option to better vision without the hassle of daily contact lens care.
If you prefer wearing glasses, you may opt to high-definition lenses to give you a sharper vision than mere regular eyeglasses.
What Exactly is “Perfect” Vision?
It is nearly impossible to pinpoint the exact meaning of “perfect” vision. A much more accurate question is, “Perfect for what?”
For example, a perfect vision for a sunny day is not a 20/20 vision who has problems seeing halos and glares. A much better vision for that could be a worse visual acuity but paired with polarized glasses with anti-reflective coating that enhances the contrast and blocks glare.
Perfect vision could also mean worse visual acuity than 20/20 vision but impressive dynamic visual skills for an athlete. This is best for the eyes to follow fast-paced moving objects in the sports field.
Visit Your Eye Doctor
A qualified and trusted ophthalmologist is the first step to better and clearer eyesight in most situations. Comprehensive eye exams and vision evaluations are given to maximize the clarity and comfort of your eyesight.
If you do not prefer wearing contact lenses or glasses to sharpen your vision, you could talk to an experienced LASIK surgeon to find the best laser vision correction options for you.
If you are looking to maximize your dynamic vision skills for activities like sports, you can visit a sports vision specialist eye doctor to know more about sports vision training. seek an eye doctor who is a sports vision specialist and ask about sports vision training.
Lastly, if your child has 20/20 vision but struggles with eye strain and other vision problems at school, it is best to seek advice from a children’s vision specialist eye doctor to guide you with learning-related vision problems.
This post is also available in: Filipino