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Medical Video: Online Eye Exam
Lately, do you have a slightly blurry or unfocused look when looking at objects at a distance? It could be that you have minus eyes. In medical terms the minus eye is called nearsightedness or miopi. So how do you know the minus eye or not? Get to know the symptoms below, let's.
What causes minus eyes?
There are several factors that cause minus eyes, namely family history and environmental influences (like watching the computer screen too long).
Simply put, the minus eye can be described like this: the light that reflects from an object enters the eye through the cornea. After that the object is focused by the eyepiece to the retina. Under normal conditions, the eyepiece and cornea refract the incoming light so that the shadow of the object is focused right on the retina.
Well, while in the minus eye, the incoming light is not focused on the retina, but it is actually far in front of it. This is what makes people with minus eyes see distant objects so they look out of focus or blurry. This condition can be caused because the cornea is too curved or the length of the eyeball is too large.
How do you know the minus eye or not?
How to know the minus eye or not is to do eye examination. These checks start from the simplest, such as reading the standard letter graphics on the Snellen card, to tests that are far more complicated by using sophisticated lenses and machines to observe the internal structure of the eye.
Examination using the Snellen card is the most common way of knowing the minus eye. This method of inspection is widely available at various eye clinics and optical equipment stores. As for the more complicated examination, it must be done in an ophthalmologist.
The steps to do an eye examination using the Snellen card are as follows.
- When you do an eye exam, you will be asked to sit or stand at a distance of 6 meters from the Snellen card.
- Then the doctor or expert will tell you to read the letters on the Snellen card using special glasses (phropter) from the top row to the bottom, so you are no longer able to read the letters on that line. Eyes with a more opaque view will be tested first.
- Using these special glasses the doctor or expert then replaces a series of lenses and measures how the lens can focus light based on your response to assessing the clarity of your views. The lens will continue to be replaced until later you really get clear and clean vision.
- Repeat this procedure for the next eye.
The doctor will do this examination without using eye drops to determine how your eyes respond under normal conditions. Usually using a snellen card and special glasses is enough as a way of knowing the minus eye or not. After doing this test the doctor will then prescribe it glasses or contact lenses that suits your needs.
