What Is a Refractive Error?

Refractive error refers to the fact that when the eye does not use adjustment, after the parallel light passes through the refractive effect of the eye, it cannot form a clear object image on the retina, and it is imaged in front or behind the retina. It includes hyperopia, myopia, and astigmatism.

Basic Information

nickname

Refractive errors, refraction errors, and different refractive errors

English name

refractive errors

Visiting department

Ophthalmology

Common locations

eye

Common causes

Genetic factors, irrational eye use

Common symptoms

Myopia, hyperopia, visual fatigue symptoms, astigmatism

Contagious

no

Clinical manifestations of refractive error

Myopia

Mild or moderate myopia, with no symptoms other than blurry distant objects. When working at short distances, you can see small targets without adjustment or less adjustment, but it is convenient, but in high myopia, work When the target distance is very close, the two eyes are too inwardly gathered, which will cause excessive use of the medial rectus muscle and symptoms of visual fatigue.

Hyperopia

The visual acuity of hyperopia is determined by the degree of dioptric power and the strength of accommodation. Mild hyperopia can be overcome with a small amount of accommodation. Far and near vision can be normal, and generally asymptomatic. Such hyperopia is called Hidden hyperopia, heavier hyperopia, or slightly inadequate adjustment power, so far and near vision are not good. The remaining part that cannot be fully compensated by the regulation is called dominant hyperopia, which is the collective name of hidden hyperopia and vision. For generalized hyperopia, hyperopic eyes are prone to vision fatigue due to their long-term adjustment tension.

3. Visual fatigue symptoms

Refers to reading, writing, or working at a short distance for a long time, blurred writing or targets, dry eyes, heavy eyelids, fatigue, and eye pain and headache. After a short rest, the symptoms are significantly reduced or disappeared. Symptoms are usually the most common in the afternoon and evening. In severe cases, nausea and vomiting can occur. Sometimes chronic conjunctivitis, blepharitis, or stye may recur.

4.Astigmatism

Those with low refractive power may be asymptomatic, slightly higher astigmatism may have vision loss, and they are not clear when looking far and near. They may have ghosting and often have symptoms of visual fatigue.

Refractive Error Examination

Subjective inspection

(1) Judgment of refractive properties based on preliminary analysis of visual inspection.

(2) Insertion optometry.

(3) Optometry of cross cylinder and astigmatism corrector.

(4) Cloud and fog method.

(5) Astigmatism table optometry.

(6) Pinhole film and slit film inspection method.

(7) Laser speckle pattern method.

2. Objective inspection method

(1) Direct ophthalmoscope inspection method.

(2) Retinoscopy.

(3) Band photomicroscopy.

(4) Corneal meter.

(5) Automatic optometry.

Differential diagnosis of refractive error

1. Myopia needs to be distinguished from pseudomyopia.

2. Hyperopia needs to be distinguished from papillitis, myopia, presbyopia, and emmetropia.

Refractive Error Treatment

Myopia treatment

Mild and moderate myopia can be corrected with moderate concave lens. High myopia often feels too small after wearing glasses, dizziness and difficulty in seeing near objects should be reduced as appropriate, or wearing a contact lens, but the latter can cause a series of corneal complications if not handled properly.

Myopic laser surgery is often referred to as "excimer laser surgery". Excimer laser is used to perform a refractive cut of the substromal layer of the corneal flap to reduce the corneal curvature of the pupil area and achieve the purpose of correcting myopia.

For myopia surgery, many people are afraid of slow recovery after surgery, which will delay work. Therefore, many patients with myopia want to know the speed of recovery of myopia surgery. The speed of vision recovery of laser myopia surgery depends on age and eye refractive adjustment. Ability and degree of myopia before surgery.

In general, young people, those with low myopia before surgery, recover faster; in addition, vision that looks far away is faster than that seen near (such as reading, looking at fine objects, etc.). Normally after a day or two of rest, you can live and work normally. However, in the process of postoperative vision recovery, attention should be paid to eye hygiene to avoid discomfort caused by eye fatigue.

2. Hyperopia treatment

For hyperopia, if vision is normal and there are no conscious symptoms, no treatment is required. If symptoms of vision fatigue or vision have been affected, wear appropriate convex lens correction. People with high hyperopia, especially children with esotropia, should wear glasses early. With the development of eyeballs, children's hyperopia has a tendency to gradually decline, so you must also check once a year to adjust the power of the glasses you wear at any time. In addition to wearing a convex lens correction, you can also use a contact lens correction.

3. Astigmatism treatment

Generally mild and asymptomatic people can not be treated, otherwise they should be equipped with cylindrical lens correction, concave lenses for myopic astigmatism, convex lenses for astigmatism.