Your Options for Achieving 20/20 Vision
Myopia, or nearsightedness, is a common vision problem that can develop during childhood. Myopia control helps maintain clear vision. Here’s when to consider it for your child.
20/50 Vision
We all know that normal visual acuity is 20/20 (feet) in the United States or 6/6 (meters) in the rest of the world. However, I didn’t understand the nuances of visual acuity tests until I analyzed several optometry and ophthalmology medical malpractice cases. After analyzing those cases, I learned that there’s much more to the documentation of visual acuity than 20/20.
The physician or technician measures and reports each eye separately, with the right eye documented first. Visual acuity is the eyes’ ability to distinguish letters at a given distance. The Snellen eye chart is one of the most common for measuring visual acuity. The chart is composed of seven lines which represent 20/20, 20/25, 20/30, 20/40, 20/50, 20/70, 20/100 and 20/200 vision. The Snellen eye chart also has several lines of smaller letters; these represent better than 20/20 visual acuity. Some charts use shapes , such as the tumbling E.
Vision measured as 20/20 is normal vision . The first and second numbers refer to how well the patient sees at a distance of 20 feet. (The actual distance in the doctor’s office may be much less than 20 feet by using mirrors projected on a screen.) A patient who can only see the top letter on the chart has 20/200 vision . This means that the patient can see at 20 feet what a person with normal vision can see at 200 feet. A patient with 20/10 vision has better than normal visual acuity, in that the patient can see at 20 feet what persons with normal vision can see at 10 feet.
The physician or technician also documents visual acuity with plus and minus signs . The minus sign refers to missed letters on a line . For example, the doctor may document 20/50-2. This means that the patient missed two letters on the 20/50 line. A plus sign refers to the patient’s ability to discern some letters on the following line. For example, 20/50+1 means that the patient read all the letters on the 20/50 line plus one letter on the next line.
Except for OD (right eye), OS (left eye), and OU (both eyes), visual acuity abbreviations are different from what most nurses encounter in their day-to-day work life. Even the abbreviation OU is slightly different in that it means both eyes together when referring to visual acuity. Some abbreviations are easy to figure out – CL for contact lenses and GL for glasses – but some are harder. Visual acuity itself is abbreviated V or VA. It may also be abbreviated as DVA, or VAd, with the ” D” meaning “distance.” Near visual acuity (NV, NVA, or VAn) is tested by the patient reading from a card held 14 to 16 inches (35½ to 40 cm) from the face. Other abbreviations frequently used in visual acuity testing:
CC refers to “with correction” while SC refers to “without correction.”
PH refers to “pinhole.” A pinhole is similar to squinting in that it removes the effects of refractive errors.
CF and FC refer to “finger counting.” “How many fingers do you see?”
HM refers to “hand motion.” If the patient cannot distinguish fingers, then the examiner determines if the patient can discern hand motion.
LP refers to “light perception” while NLP refers to “no light perception.”
What does visual acuity mean to legal nurse consultants? If a physician or technician improperly performs visual acuity testing, it’s a standard of care issue. However, my experience with optometry and ophthalmology cases has been in determining damages . Those damages included poor visual acuity, even blindness, due to allegations of failure to refer patients, failure to diagnose and treat eye conditions, and/or improper performance of eye procedures. Analyzing the results of visual acuity tests prior to and after the incident provides the basis for the claim of damages and the extent of those damages.
Your Options for Achieving 20/20 Vision
We talk a great deal about 20/20 vision, but what does this really mean? Do you have it? If not, how can you achieve it?
As experienced optometrists, Dr. Curtis Frank and the team here at Vision and Ortho-K have devoted our practice to helping people to achieve great vision. It might surprise you to know that not many people have natural 20/20 vision, as nearly 200 million adults in the United States wear corrective lenses.
In the following, we explore what 20/20 vision means and how we can help you to see more clearly.
Understanding 20/20 vision
The concept behind 20/20 vision is quite simple — you’re able to see something clearly that’s 20 feet away from you. We consider this to be normal visual acuity, so it’s not correct to assume that 20/20 vision is perfect.
People who have 20/15 or 20/10 vision, for example, can see something at 20 feet that people with normal vision would only see at 15 or 10 feet.
On the flip side, when you have 20/50 vision, for example, you see something clearly 20 feet away that people with 20/20 vision can see at 50 feet.
As the bottom number climbs, it means that your visual acuity goes down. When the number reaches 20/200, we consider this to be legally blind.
Another important point about 20/20 vision is that this doesn’t apply to other vision problems, such as a loss of peripheral vision, lack of depth perception, or color blindness.
Problems that affect 20/20 vision
There are several issues that can prevent you from having normal 20/20 vision, such as:
- Myopia — you don’t see clearly at a distance
- Hyperopia — you don’t see objects close to you clearly
- Astigmatism — an irregular curve in your cornea that creates vision issues
- Presbyopia — age-related inability to focus on objects close to you
These vision issues are grouped under refractive errors, which means your eyes aren’t bending light correctly, causing light to fall in front of or behind your retina.
Achieving 20/20 vision
After a comprehensive eye exam to determine your vision number, if we find that you do have a refractive error, there are many ways we can help you see more clearly, such as:
- Eyeglasses
- Prescription sunglasses
- Contact lenses
- Ortho-k lenses
- Scleral lenses
Many people opt for LASIK surgery, a technique in which your cornea is reshaped to help correct the refractive error.
Determining which solution is best for providing you with 20/20 vision is a decision only you can make. Some people dislike the idea of contact lenses or the lenses feel uncomfortable, in which case they choose glasses or surgery. In other cases, people prefer glasses, especially if they only need them for certain activities, such as driving.
Of course, we can help guide you in your decision-making, and we’re happy to help you try out different lenses to ensure you find one that’s comfortable.
To get on the road to 20/20 vision, schedule an appointment at one of our offices in Boston or Newton Upper Falls, Massachusetts.
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