Basic eye defects include farsightedness, nearsightedness and astigmatism. Less often, we can also encounter color blindness, i.e. a color vision disorder.
Farsightedness and nearsightedness
Farsightedness , or hypermetropia, is an eye defect caused by an imbalance between the length of the eye and the refraction of the optical environment of the eye. The eye of a farsighted person is strained by constant focusing (retracting the lens), which can cause problems such as increased fatigue, burning or eye pain.
Short-sightedness , or myopia, is one of the most common eye defects. This is a condition where you can see nearby objects without problems, but further away they appear blurry. Symptoms of myopia can be, for example, headaches , because a short-sighted person has to strain to focus his attention on more distant objects.
From the comfort of your home, you can now test how well you can see with the following tests.
Hypermetropia and myopia test
The letter table below the screen is used for this test. Sit at a distance of 3 meters from the monitor, cover one eye with your hand (if you already wear prescription glasses, keep them but cover your eye with paper for example) and start reading the letters from the first picture. Follow one line from top to bottom. Do the same with the other eye . If you can read the second to last line (6/6), your distance vision should be fine. However, if you can’t see clearly from a certain line, you probably need glasses or higher diopters.
Visual acuity test (distance vision):
Astigmatism
Astigmatism is an eye defect in which one of the optical surfaces of the eye (most often the cornea) is irregularly curved, instead of a regular spherical shape, it has an irregular shape resembling a rugby ball.
Astigmatism often occurs together with nearsightedness or farsightedness. A person suffering from astigmatism has distorted or blurred vision both near and far. Astigmatics often have trouble focusing, they have a harder time perceiving contrasts, fine points, lines or straight lines.
Diagnosis of astigmatism
Follow these guidelines to find out if you have astigmatism. Take off your glasses. If you wear contact lenses, keep them on your eyes. Close or cover one eye, remember to keep a distance of at least 35 centimeters from the screen. Look at the picture.
With healthy or properly corrected vision, you should see a series of concentric circles with sharp black and white contrast. If you see shades of gray rather than black or white that create a uniform field, you should see your optician or eye doctor.
Color blindness
Color blindness is a color vision disorder of the human eye caused by a disorder of retinal cells. It affects a small percentage of the population. The most common case is the inability to distinguish red, green or blue-violet colors, less common is color blindness to yellow and blue. Colorblindness to all colors is rare, where a person sees only in the gray scale.
Diagnosis of color blindness
Tests that help detect color blindness are based on color discrimination of numbers. They look like colored clusters of spots that should create a specific sign to a healthy eye .
Look at the following image:
Giant. 1: When you see the number 3, You have a color perception disorder of green and red colors. A healthy person sees the number 8. Fig. 2 : A healthy person sees the number 15. One who has a disorder of the perception of green and red reads 17. Fig. 3: When your eyes are fine, you see 5. When not, you suffer from a green-red perception disorder and see the number 2. A person who is completely color blind cannot distinguish a number at all.
Giant. 4: The number 73 sees the healthy eye. When you see 28, go to the eye doctor. Giant. 5: This distinct twelve can be seen by a healthy person and a color-blind person. Giant. 6: Here we see 74 without a defect, with a defect in green and red we perceive 21. Again, a color blind person does not see the number at all.
Please evaluate the results of all these carefully (it may also depend on the color resolution of the monitor) For best treatment contact your doctors in your region.