【Causes・Disease】

Refractive errors are a type of vision problem that makes it hard to see clearly.
Refractive errors are divided into myopia, hyperopia, and astigmatism. These symptoms are caused by the inability of light to focus on the retina. Compared with emmetropia (the state of focusing on the retina), short vision, far vision or both may appear blurred.
If you compare the eye to a camera, just as a camera has a lens and film, in the eye, the “cornea” and “lens” are aligned with the lens and the “retina” is aligned with the film. Usually, the light entering the eye will go through the cornea and the lens, focus on the lens and finally form visual object structure.

◎myopia

Myopia is caused by the long eyeball, and the light is focused in front of the retina. You can see near objects, while things far away are blurry. Myopia can be corrected with concave lens which is marked with minus (-) degree.

◎hyperopia

Hyperopia is caused by the short eyeball and the light is focused behind the retina. Unlike myopia, people with hyperopia cannot see both far and near clearly. It can be corrected by the convex lens, which is marked with a plus (+) degree.

◎astigmatism

Astigmatism is caused by distortion of cornea and lens. Light cannot be concentrated in one place, and the image may look blurry. Usually, like myopia and hyperopia, astigmatism can be corrected with corrective lenses (cylindrical lenses), but abnormal astigmatism caused by corneal diseases is difficult to be completely corrected.

【Treatment】

The general correction methods of refractive abnormality are glasses and contact lenses.
In recent years, we can choose treatment according to patients’ adaptability and lifestyles. For children, there is Myopine eye drop treatment which can inhibit the deterioration of myopia. Patients can also wear special hard contact lenses which is called Orthokeratology while sleeping to correct myopia by correcting corneal shape.
Patients who want to live with naked eyes can choose LASIK surgery or ICL surgery (intraocular lens).
Glasses can be easily put on and cared for. But the lenses may get cloudy if there is a temperature difference. Glasses can also be annoying when doing exercise.
Unlike glasses, although contact lenses will not get blurry, patients may feel dry or a foreign body sensation. In addition, wearing contact lenses for a long time may also lead to complications such as corneal epithelial injury and corneal ulcer, so proper management is necessary.
LASIK surgery or ICL surgery can free patients from glasses and contact lenses. Patients can see clearly with their naked eyes even at an emergency circumstance or a disaster. Surgeries can improve quality of life; however, each surgery has its only advantages and disadvantages, it is important to consider if it is suitable for you.
The methods of correction vary depending on patients’ eye conditions, lifestyles, and patients’ own choices. It is important to undergo eye examinations in eye clinics and take advice from professional doctors before you decide.