Alternating eyes

Introduction Alternate view: The lens is designed to move in the gaze direction on the cornea so that the far and near areas can be almost completely covered on the pupil. Long-distance or close-range viewing allows the line of sight to be alternately selected through different areas of the pupil. Alternate view: In cases with good binocular vision, both eyes can look at the target, and can use two eyes alternately. The other case is that the child is myopia at one eye and the right eye or mild hyperopia at the other eye. When you are close to seeing myopia, look at the distance when you use the face or the farsighted eye to form a pattern of alternate use of both eyes. Although only one eye is used at a time, since there is no adjustment and collection when looking at the distance, there may be no Any symptoms. The patient only looks into the distance with one eye and only looks close at one eye. In the long run, the visual function will be greatly reduced, forming an "alternating view", destroying the normal visual three-dimensional sense, and serious strabismus. It is a clinical symptom of anisometropia. The anisometropia refers to the diopter of both eyes. If the degree differs by more than 2.00 D, symptoms usually appear due to difficulty in fusion. Because the eye-regulating activity is simultaneous in both eyes, the ametropia is often in a visually blurred state, which is prone to cause amblyopia. The anisometropia of the hyperopic person has a higher degree of the eye. The amblyopia is mostly congenital. And often combined with varying degrees of facial developmental asymmetry. The refractive state and degree of the two eyes are different. Generally, the difference between the two eye degrees exceeds 250 degrees, which is called anisometropia.

Cause

(1) Causes of the disease

The main factors that can cause anisometropia include:

1 Developmental factors: During the development of the eye, the degree of hyperopia is continuously reduced, while the degree of myopia is constantly developing. If the development progress of the two eyes is different, it may cause anisometropia;

2 abnormalities of binocular vision: anisometropia often occurs after strabismus, mainly due to the influence of strabismus or the process of erecting the eyeball, which interrupts the development of binocular vision;

3 trauma and other diseases can also cause anisometropia: the incidence of anisometropia in patients with ptosis is about 55%, other such as orbital hemangioma, retinopathy (glass volume blood, etc.), nuclear cataract, etc.; 4 surgical factors Some surgery can cause artificial anisometropia, such as implantation of intraocular lens, corneal transplantation, RK surgery and so on.

According to the etiology of the disease can be classified as follows: hereditary (hereditary), including congenital glaucoma, congenital cataract and some diseases that cause eyelid closure, such as congenital oculomotor nerve paralysis, ptosis, etc.; acquired (acquired), Including traumatic, intrabulbar or peribulous space-occupying lesions and iatrogenic factors, such as aphakic eyes after monocular lens removal, refractive surgery, penetrating keratoplasty.

(two) pathogenesis

It is generally believed that the development of anisometropia is influenced by genetic factors, but the exact mechanism is still unclear.

an examination

Related inspection

Refractive vision

1. Mild anisometropia can be without any symptoms.

2. Monocular vision: The anisometropia exceeds a certain degree, and the binocular single vision function is destroyed. In the stage of visual development is not mature, in order to avoid the interference of the blurred image, it will involuntarily suppress it, and the child is not a double eye. Vision, but single-eye single vision, that is, only use the eyesight with better vision, the other eye is discarded, and the monocular vision has no normal depth perception and stereo vision.

3. Amblyopia: After the monocular vision is formed, the retina of the main eye is constantly subjected to normal visual stimulation, and the visual information is transmitted to the visual center through the visual path to form vision, and the visual function can be normally developed, and the disused eye is blurred. The image of the object and the information it produces are suppressed. The visual center does not respond to the visual information of the eye. Over time, amblyopia is formed. Under normal circumstances, the degree of refractive error of the amblyopic eye is greater than that of the other eye. A large amount of data indicates that the hyperopicity is high. The incidence of amblyopia amblyopia is high. In children with anisometropic amblyopia, most of them are hyperopic anisometropia. The degree of amblyopia is related to the age at which anisometropia occurs. The younger the age, the more severe the degree of amblyopia may be. Most scholars believe that Myopic anisometropia is less likely to cause amblyopia because myopia is more normal in myopia. At the same time, myopic anisometropia occurs later, rarely in the sensitive period of visual function development, even if myopia is refraction. Staggered causes amblyopia, and the degree is often lighter.

4. Strabismus: Amblyopia is not necessarily accompanied by strabismus, but if the eye function is suppressed for a long time and discarded, it is prone to strabismus.

5. Alternate view: In cases with good binocular vision, both eyes can look at the target, and can use two eyes alternately. In another case, one eye is myopia, the other eye is frontal or mild hyperopia, will not Self-seeing near-sighted use of myopia, seeing the distance with long-sighted or far-sighted eyes, forming a pattern of alternating use of both eyes, although only one eye is used at a time, but because of the distance, no adjustments and collections are used when looking at the near, so There may be no symptoms.

Differential diagnosis

Simultaneous view: the light can pass through the far and near optical zone at the same time. If the patient looks at a distant object, the light forms a clear image on the retina through the far optical region, and forms a non-retina focus through the near optical region. . Conversely, if the patient looks at a nearby object, the light forms a clear image on the retina through the near-optical region, and the light through the far-optical region forms a focus outside the retina, resulting in some blurring due to defocus. The difference between myopic and farsighted anisometropia:

1. In the myopic anisometropia, the same vision correction in both eyes is more common than the hyperopic anisometropia. The unequal vision correction is more common in hyperopic anisometropia, and the difference in visual acuity between the two eyes is also greater.

2, better eyesight correction with the increase of refractive error and decreased, in the hyperopic anisometropia, reduce more.

3. In myopic anisometropia, the corrected eyesight of the eye decreases with the increase of the refractive error, which is larger than that of the contralateral eye. In the hyperopic anisometropia, with the increase of the refractive error, Eyesight decreases rapidly, and the eye is more prone than myopic anisometropia.

4. The average corrected visual acuity of hyperopic anisometropia is worse than the myopic anisometropia. The anisometropia and the two-eye images are different: they exist at the same time, and they can exist alone. For example, when the ametropia glasses are placed on the anterior focal plane of the axial ametropia, the size of the omentum image will be squared. The same is obtained (Knapp's law). In the following cases of anisometropia, images often appear, such as eye swelling, dizziness, vision and even diplopia.

5, related to the degree of anisometropia, less than 1D of anisometropia about 25% of the people appear in the image, ginseng is 1 ~ 2D, 50% of the image appears, and anisometropia > 2 ~ 3D It is not easy to achieve binocular vision, resulting in reduced image unequalness. In other words, the image difference of 0.75~1.5% is generated. In the total population, about 3~5% of the people have different images.

6, the refractive error of the visual acuity after retinal detachment, often found that the image is not equal.

7, single-eye aphakic lens is corrected with contact lens, and some people have different images.

8, astigmatism caused by corneal wound suture or keratitis after healing, often caused by acute images.

9, macular edema often cause acute images.

10. Since the size and shape of the image on the retina are suddenly changed after wearing or removing the prism, it is also possible to wear a pair of new glasses, and the image size varies due to the change of the refractive power. The image unequal is related to the degree of image unequal. The difference between the two eyes is 1~5%, which can produce pseudo spatial positioning. The image difference is less than 2%, and only the spatial dislocation occurs. According to the results of binocular optometry, the diagnosis can be confirmed.

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