Test Yourself for Astigmatism
In THREE Easy Steps



WHAT IS ASTIGMATISM?

Astigmatism is a common eye focusing problem where light rays entering the eye become focused by the cornea and lens at different distances from the retina. This causes some parts of the image to be more out of focus than others, thereby affecting your visual acuity. Astigmatic errors are due to the shape of the eye being irregular, such that it is shaped more like an oblong football rather than a basketball.

Astigmatism can occur due to an irregularity of the shape of the cornea or lens or both. This results in the light rays in the horizontal and vertical planes being focused at different locations. In an eye without astigmatism, the light rays in the horizontal and vertical planes become focused at one single point, giving a crisp and sharp image.

This condition is sometimes inherited, but it often occurs as a normal characteristic of growth. Sometimes, this can be due to keratoconus, corneal transplant surgery, previous injury, or to something pressing on the eyeball, such as an eyelid stye. Astigmatic errors occur in around 30% of children and adults.


SELF TESTING FOR ASTIGMATISM

There are 2 common self-test methods for astigmatism - the Dial Test and the Line Test. Both are easily done in 3 simple steps. Do remember that most people have a small degree of astigmatic error, and that the most definitive way of evaluating this is through refraction by your optometrist or ophthalmologist.


● DIAL TEST

(Image adapted from the internet)

Instructions:

1. Position yourself 3 meters or 10 feet from the dial chart

2. Cover each eye at a time

3. Observe the lines with each eye carefully.

All the lines are black in color. You are likely to have some degree of astigmatic error if some lines appear black while others seem gray.




● LINE TEST

(Image adapted from the internet)

Instructions:

1. Position yourself 3 meters or 10 feet from the line chart

2. Cover each eye at a time

3. Observe the lines with each eye carefully.

All the lines are black in color. You are likely to have some degree of astigmatic error if you do the squares appear gray or not to have the same black color.



The best and most accurate way, of course, is to have your refraction properly tested by your eye care professional (either your optometrist or ophthalmologist). The line and dial tests will tell you whether or not you have astigmatic error. However, it does not tell you how much astigmatic error you may have.

From the refraction, you will obtain 3 numbers: the sphere, the cylinder and the axis. The cylinder is the number that denotes the amount of astigmatic error that you have. This is then incorporated into your glasses for correction so that you can see crisply again!




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