With normal vision, light reflected from an object enters the eye through the cornea (the curved, transparent surface that protects the front of the eye). Because the cornea focuses (refractors) these light rays pass through the eye's natural lens, where they are converged to focus at a sharp point on the retina (the back layer of the eye that contains sensitive cells). with light). Retinal cells convert light rays into electrical impulses that are sent to the brain (via the optic nerve) and processed to form images.
Refractive error is a phenomenon in which light from an object does not reach the retina but is in front or behind or many points on the retina, causing the image of the object to be blurred and we will not be able to see the object clearly.
2. Causes of refractive error
The main reason is that due to the rapid development of technology, people are increasingly dependent on electronic devices with blue light that is harmful to the eyes, especially children's early exposure to gadgets. technology at an increasing rate. These refractive errors will affect and cause difficulties in daily biology as well as in studying, working and daily activities.
3. Symptoms of refractive errors
Blurred or distorted vision
Difficulty focusing on near or far objects
Squint to read
Color blindness: color blind test
Eye strain or fatigue
If you experience any of the above symptoms, you should see your doctor for a general eye exam.
4. Effects of refractive error
There are 4 types of refractive errors: Myopia, Farsightedness, Astigmatism, Presbyopia, of which myopia accounts for more than 70% of refractive errors in Vietnamese children. In 2010, there were only about 1.8 billion people in the world with refractive errors, but by 2020 this number has doubled. In developing countries, where people are less interested in regularly checking their vision health, this rate is especially increasing rapidly and much higher. In Vietnam alone, the rate of myopia has reached over 38%.
