Definition of amblyopia: The standard set by the National Strabismus and Pediatric Ophthalmology Group Working Meeting in 1996: Any person who has no obvious organic lesion in the eye, and whose distance vision is mainly caused by functional factors <0.9, and cannot be corrected, is called amblyopia. However, there is some controversy about this, some scholars believe that the visual acuity before the age of five, in 0.6 is normal. In the recent 15th Ophthalmology Congress, the Strabismus and Pediatric Ophthalmology Group defined amblyopia as a condition in which the best corrected visual acuity in one or both eyes is lower than the corresponding chronological visual acuity, or the visual acuity in both eyes differs by more than two lines, due to monocular strabismus, uncorrected refractive error and high refractive error and form deprivation during visual development.
The lower limit of normal visual acuity for children in different age groups: 0.5 for 3~5 years old, 0.7 for 6 years old and above
Classification of amblyopia:
I. Strabismus: internal strabismus is the most common
Refractive error: farsightedness is the most common, but also myopia or various kinds of astigmatism
Refractive aberrations: farsightedness is the most common, but there are also individuals with large myopia in one eye
Formal deprivation: due to refractive interstitial clouding, such as congenital cataract, but also keratoconus, congenital ptosis, etc. The best year for amblyopia treatment
Amblyopia treatment should begin at the age of three because children at this age are cooperative in their examinations, and their visual development and eye development are closer to that of adults, and there is no hope of curing amblyopia if they are more than eight years old.
Amblyopia diagnosis and treatment procedures
I. Visual acuity examination, using the international standard visual acuity chart
Regular dilated eye examinations to correct visual acuity (using atropine to dilate the pupil)
Third, confirm the diagnosis of amblyopia, either binocular or monocular
IV. Wear appropriate glasses
Five, choose the treatment method
Amblyopia treatment methods.
I. Conventional masking therapy: divided into (complete masking, half masking)
Conventional masking therapy: according to the difference of binocular vision, cover the healthy eye or high vision eye.
Reverse masking refers to the amblyopic eye for paracentral gaze, in order to change the nature of gaze, first cover the amblyopic eye. When the amblyopic eye changes to central gaze, it will be replaced by regular masking, but it is rarely used in clinical practice.
Several issues should be noted in masking therapy.
1, the beginning that cover the healthy eye, complete cover, no need to use 1:6, 3:3 and other methods, because the real cover amblyopia almost rarely occurs, once it appears, lifting the cover can be, cover requires the cooperation of the child, perseverance and parental and teacher supervision.
2.After both eyes have parallel vision, change to semi-covering, that is, the healthy eye is covered with cellophane, so that its visual acuity is lower than that of the amblyopic eye, in order to consolidate the effect of treatment, and then gradually lift the cover completely.
3, can be combined with other treatment methods such as red glass film, posterior image therapy, CAM stimulation and laser and other new methods, that is, masking plus fine work practice, treatment can be appropriate to the healthy eye dilated pupil.
4. Emphasize that the masking must be strict, and the more thorough the strict masking, the better the treatment effect.
Second, suppression therapy (optical drug suppression therapy).
This method is older, first proposed by European scholars, there are far repression, near repression and other methods, but in practice, we believe that the most suitable for the treatment process of refractive parallax amblyopia, after complete masking, amblyopic eye vision progress, up to a certain degree, in order to consolidate the effect, and to lift the pain of masking, available repression therapy.
Advantages of suppression therapy.
On the basis of masking, the amblyopic eye progresses and reaches a certain degree when used, the masking can be lifted, which is conducive to the physical and mental acceptance of the child and parents, and the appearance is painless, the effect is reliable, and no masking amblyopia occurs.
Disadvantages: frequent replacement of glasses is required, sometimes just with the mirror can be suppressed, but after a few months, that is, the tendency to suppress, the dominant eye glasses may need to replace a larger degree lens, costly.
In addition, it should also be noted that due to wearing larger farsighted glasses, there is a possibility of adjustment paralysis, producing exotropia, therefore, the need for frequent and regular follow-ups in treatment is emphasized, and once it occurs, it is promptly disposed of.
Other treatments for amblyopia.
CAM therapy: grating therapy
Posterior image therapy
Red filter stimulation therapy
Laser therapy, in fact, is a derivative of red filter therapy.
These methods, which are generally based on the wearing of appropriate glasses and after masking therapy, are often used as adjunctive therapies in the treatment process.
If there are no conditions to apply these methods, they can be treated by applying fine work methods at home, such as: writing, drawing, threading beads, threading needles.
Remember, amblyopia is caused by loss of use, and finding ways to enhance the use of the amblyopic eye is treatment.
Principles of amblyopia in children and its prescription of mirrors.
Selection of farsighted glasses
For hyperopic eyes, after atropine pupil dilatation, the vision correction is routinely performed with shadowing, computerized optometry and trial lenses, with the shadowing generally at a distance of 0.5 meters.
For example, in a child with internal strabismus, the results of a half-meter shadow check after pupil dilatation are: right + 6D, left + 7D, neutral shadow movement, and computerized optometry may be right + 6D, left + 7D.
The prescription is: right + 3D, left + 4D. This is a full prescription, i.e., minus the half-meter examination and 1D adjustment (10 years old should have 1D adjustment)
Right + 6D-2D-1D = 3D
Left + 7D-2D-1D = 4D
This is the regular prescription in usual cases, especially for hyperopia without internal strabismus, which should be given full correction.
However, in clinical practice, children with hyperopia with internal strabismus are often prescribed with overcorrection, as in the above example.
The result of the semimetric examination was right + 6D and left + 7D.
The prescription for spectacles is right + 4D, left + 5D
Here the prescription is only subtracted from the +2D neutralizing lens of the semimetric examination, while retaining the due +1D adjustment, that is, the overcorrection glasses.
After the prescription, the lenses are usually worn routinely for 2 months first, and then reviewed after they have completely relaxed their own adjustment, and the masking treatment is carried out according to the corrected visual acuity of both eyes after wearing the lenses.
Generally speaking, when the difference in corrected visual acuity between the two eyes is more than 2 lines, the dominant eye should be covered.
Common phenomena in the process of wearing farsighted glasses.
1. When you first wear glasses, your corrected visual acuity may not be as good as your vision without a mirror.
2. When first wearing glasses, their corrected visual acuity is the same as without glasses.
These two occurrences are caused by not relaxing the adjustment sufficiently. During the process of wearing glasses, the visual acuity will gradually increase as its own adjustment disappears.
The ophthalmologist should learn to use the method of shadowing for optometry and computerized optometry as a reference for prescription lenses.
The ophthalmologist should be familiar with the basic knowledge of refraction, spectacles and vision correction.
Common problems in the treatment of children with hyperopia and internal strabismus who wear mirror masking.
1. After wearing a mirror, the eye position is corrected, but after removing the mirror, the strabismus is aggravated than before wearing a mirror.
This is a typical case of adjusted internal strabismus, and parents must be convinced to insist on wearing it.
2. After wearing the mirror, the vision is not parallel, but the eye position is correct, and after covering the dominant eye, the strabismus is aggravated.
This is also a typical case of regulatory internal strabismus, in which the strabismus is aggravated by covering one eye, but the eye position will naturally become correct after the vision is parallel and the covering is lifted.
Follow-up time for hyperopic internal strabismus.
After the first dilated eye exam and the glasses, a review should be performed at two months to detect amblyopia and perform treatment such as masking.
Subsequent reviews should be performed at least once every three months during the course of masking treatment.
At one year, you must have a new dilated eye exam and, depending on the situation, be refitted with glasses.
There may be two conditions.
1. Decrease in the degree of hyperopia: A new prescription should be issued.
2. No change in the degree of hyperopia: the original glasses can be worn, but if the lenses are badly worn, a new pair of glasses should be prescribed.
For moderate to high hyperopia and above, the wearing time may be longer, ranging from about 10 years, and parents should be informed of this.
The evolution of refractive error is that farsightedness gradually decreases with the growth of age, and some low and medium farsightedness may become myopia. High hyperopia may be lifelong. Myopia generally grows with age, but of course it is related to genetics, eye hygiene and environmental factors, and myopia tends to stabilize around age 20.