Question

Examination with the Snellen chart reveals that a client has a visual acuity of 20/60. The nurse recognizes that the client: A. Has better than \(20 / 20\) vision. B. Is by definition legally blind. C. Has a slight astigmatism that can be corrected. D. Can see at 20 feet what others see at 60 feet.

Short answer

Answer: D. Can see at 20 feet what others see at 60 feet

Step-by-step solution

Understand the meaning of 20/60 vision

According to the Snellen chart, a person with 20/60 vision can see at a distance of 20 feet what a person with normal (20/20) vision can see at a distance of 60 feet.

Evaluate each statement based on the meaning of 20/60 vision

A. Has better than \(20 / 20\) vision - This statement is false. A person with 20/60 vision has worse vision than 20/20, not better. B. Is by definition legally blind - This statement is also false. Legal blindness is typically defined as having a visual acuity of 20/200 or worse. A person with 20/60 vision is not legally blind. C. Has a slight astigmatism that can be corrected - This statement is not necessarily true. A person with 20/60 vision may or may not have astigmatism, and the exercise does not provide enough information to confirm or deny this. D. Can see at 20 feet what others see at 60 feet - This statement is true. As we discussed in Step 1, a person with 20/60 vision can see at a distance of 20 feet what a person with normal vision can see at a distance of 60 feet.

Choose the correct answer based on the analysis of statements

Based on our evaluation, the correct answer is D. A person with 20/60 vision can see at 20 feet what others see at 60 feet.

Key concepts

Snellen Chart

The Snellen chart is a commonly used tool for measuring visual acuity. It consists of rows of letters, with each row corresponding to a different level of visual acuity.

When you take a vision test, you stand a specific distance away from the chart, usually 20 feet in the United States, and read the letters out loud. As the letters decrease in size, your ability to discern them becomes an assessment of your visual acuity. This measurement informs eye care professionals about the sharpness or clarity of your sight at a distance.

History of the Snellen Chart

Developed by Dutch ophthalmologist Hermann Snellen in the 1860s, the chart has since become a standard in eye care. It's not just for assessing whether you need glasses; it can also help detect eye conditions early on.

20/60 Vision

Having 20/60 vision means that what you can see clearly at 20 feet can be seen by a person with normal vision from 60 feet away. In essence, you must be closer to see an object that someone with 20/20 vision can see from farther away.

Note that visual acuity is not static and can change with lighting, contrast, and many other factors. A person with 20/60 vision does not have perfect vision, but it is not considered a severe visual impairment. They are often able to function quite well with the help of corrective lenses.

Impact on Daily Activities

People with 20/60 vision may experience difficulty with certain tasks, such as seeing a television clearly from a typical viewing distance or recognizing faces from afar. However, they typically do not have significant limitations in everyday life.

Legal Blindness

Legal blindness is defined in many jurisdictions as having a visual acuity of 20/200 or worse in the better eye with the use of corrective lenses, or having a field of vision that is 20 degrees or less. It is not based solely on acuity; it also considers the visual field.

A person who is legally blind may qualify for certain benefits and protections under the law, even though they still may have usable vision. Being legally blind does not mean that a person cannot see anything; rather, their vision is significantly impaired beyond what conventional glasses or contact lenses can correct.

Legal Blindness vs. Total Blindness

It's a common misconception that legal blindness is equivalent to total blindness. Many people who are legally blind have some usable vision and can often perform daily tasks with the assistance of vision aids or adaptations.

Astigmatism

Astigmatism is an imperfection in the curvature of your eye's cornea or lens, causing blurred or distorted vision. People with astigmatism have a cornea or lens that is not perfectly round, resembling the shape of an egg rather than a soccer ball.

It's a common condition and can exist on its own or in combination with other refractive errors like nearsightedness (myopia) or farsightedness (hyperopia). Astigmatism can be corrected with glasses, contact lenses, or refractive surgery depending on its severity.

Diagnosing Astigmatism

An eye exam by an optometrist or ophthalmologist, which includes testing with a Snellen chart, can diagnose astigmatism. Once detected, the healthcare professional will discuss treatment options to enhance visual quality.