Dr. Anthony Roberts founded Shady Grove Ophthalmology in 1996 and has since attended to over 81,000 Lasik and other refractive procedures. A career ophthalmologist, one of the primary vision acuity tools Dr. Anthony Roberts uses is the Snellen chart. Various charts exist for the initial eye test at a doctor’s visit, with different visual aids such as patterns, images, and letters to determine visual acuity depending on the patient's age and familiarity with the Latin alphabet. However, most ophthalmologists use the Snellen chart for those adept at reading due to standardization across eye care providers and opticians, ease of use, and a well-defined visual acuity grading determination model. Developed by Dr. Hermann Snellen in the 1860s, the chart contains 11 rows of capital letters. The first line has one large letter, with the successive rows gradually increasing the number of letters but reducing the size. During this evaluation, one must stand 20 feet (six meters) from the chart and attempt to read while closing one eye, without any visual aid. The assessment is over when the line can no longer be discerned. Normal vision falls at 20/20—6/6 for metric system countries—which means the Snellen chart can be read correctly and efficiently, typically up to the eighth line, from 20 feet away without corrective aids. However, this does not imply perfect vision, as 20/15 people have sharper vision and can decipher letters from 20 feet away that the 20/20 group can only see at 15 feet. Conversely, an increase in the second number proportionately implies worsening visual acuity. A 20/40 classification means that a person can correctly read the chart at 40 feet whereas a person with 20/20 vision can see it at 20 feet. In most states, a individual can fall into the legally blind category if your number is 20/200 and above. The Snellen chart is useful in determining the corrective aids required as well as eligibility for some tasks, including driving, the armed forces entry, and factory jobs qualifications.

1. Understanding the Snellen Chart
Dr. Anthony Roberts

2. Introduction
Dr. Anthony Roberts founded Shady Grove Ophthalmology in 1996 and has since
attended to over 81,000 Lasik and other refractive procedures. A career ophthalmologist,
one of the primary vision acuity tools Dr. Anthony Roberts uses is the Snellen chart.

3. Various charts exist for the initial eye test at a doctor’s visit, with different visual aids
such as patterns, images, and letters to determine visual acuity depending on the
patient's age and familiarity with the Latin alphabet. However, most ophthalmologists
use the Snellen chart for those adept at reading due to standardization across eye care
providers and opticians, ease of use, and a well-defined visual acuity grading
determination model.

4. Developed by Dr. Hermann Snellen in the 1860s, the chart contains 11 rows of capital
letters. The first line has one large letter, with the successive rows gradually increasing
the number of letters but reducing the size. During this evaluation, one must stand 20
feet (six meters) from the chart and attempt to read while closing one eye, without any
visual aid. The assessment is over when the line can no longer be discerned.

5. Normal vision falls at 20/20—6/6 for metric system countries—which means the
Snellen chart can be read correctly and efficiently, typically up to the eighth line, from 20
feet away without corrective aids. However, this does not imply perfect vision, as 20/15
people have sharper vision and can decipher letters from 20 feet away that the 20/20
group can only see at 15 feet.

6. Conversely, an increase in the second number proportionately implies worsening visual
acuity. A 20/40 classification means that a person can correctly read the chart at 40
feet whereas a person with 20/20 vision can see it at 20 feet. In most states, a
individual can fall into the legally blind category if your number is 20/200 and above.
The Snellen chart is useful in determining the corrective aids required as well as
eligibility for some tasks, including driving, the armed forces entry, and factory jobs
qualifications.