Eye test chart - Common concerns with Snellen eye test chart
Eye tests chart can vary from country to country but in the United Kingdom, the Optometrist records your visual acuity using Snellen Letters.
An eye test chart
Eye Test Char
Is made up of various sized letters, numbers and pictures to determine Visual acuity - the ability to see with glasses or contact lenses. Eye testing charts are essential to determine where you vision lies. normal?
The optometrist eye testing room has undergone many changes over the years.
Gone are the days of a box on wall containing letters illuminated from behind. Although some older optician clinics still use this type of eye chart.
The modern testing room will either consist of a projection of an eye test chart onto a wall plate or state of art LCD using a mirror.
A patient taking the test covers one eye, and reads aloud the letters of each row, beginning at the top. The smallest row on the eye test chart that can be read accurately indicates the patient’s visual acuity in that eye.
After consultation with a UK Optometrist EyeTest.info have listed some of the common questions and concerns about the Eye test chart.
What is considered normal vision?
Normal visual acuity is 6/6. Just a size which considered
The first number represents the test distance, 6 metres. The second number represents the certain size of Snellen letter on the eye chart.
What is 20/20 vision?
In the UK we work in Metric compared to Feet in the USA.
In Metric Acuity, 20/20 equals 6/6. The conversion is that 20 feet equals approximately 6 meters (actually 6.096).
What do all the numbers mean?
In order to make comparisons visual acuity achieved is expressed as a fraction - the standard chart distance is six meters, normal acuity is designated 6/6, and other acuities are expressed as ratios.
A rough comparison of Visual acuities on Eye test chart
6/3 Not many people achieve this - sniper perhaps
6/4.5 Excellent
6/6 Normal standard
6/7.5 Able to see telex text on TV
6/9
6/10 Driving standard equivalent
6/12
6/15
6/30
6/60
Eye test Chart - Driving standard?
The current number plate standard is equivalent to 6/10, this not precise.
In the United Kingdom, the legal standard of vision for driving is the ability to read a number-plate in good daylight with glasses, if worn, at the legal distance. In practice, this means a number-plate with letters measuring 31/8 in (79 mm) in height placed at a distance of 67 ft (20.5 m); however, this is often an arbitrary distance subjectively determined by the Driving examiner.
I cant read the bottom line, is my eyesight poor?
The number one concern, however we have letters that are smaller than normal vision, as a rare few have been gifted by the gods with hyper acuity they could probably read “made in Great Britain” if it was available on the eye test chart.
What about patients who don’t know the alphabet?
Some eye test charts use a series of “Es” facing different directions; he objective is to identify the directions of the letters for people who can’t read. For children the optometrist selects pictures of common everyday objects. E.g. dog, car, duck, flower.
Do you use the same eye test chart every time, and how do you stop cheating or memorising.
Modern eye charts have different variations they can use, using mixtures of letters and numbers. The Optometrist has usually memorised every letter so they don’t always look at the eye test chart.
Should I guess the letters even if I cant see them? Imp scared of getting it the eye test wrong.
Despite the name Eye test, the optometrist is not looking for strict pass or fail. We encourage you to do your best. Sometimes letters on the eye chart like an X can be confused for a K, O for a D; it’s not your fault.
Visual acuity what does the minus and plus mean on my prescription record
Optometrist want to record the best Visual acuity line read, adding minus for incorrect letters read out or plus a few extra letters on the next line is seen.
E.g. 6/10-2 missed to letters on this line or 6/6+2 read a couple of lines from next line.
