I. What is amblyopia
The latest diagnostic criteria for amblyopia established in September 2010 by the Strabismus and Pediatric Ophthalmology Branch of the Chinese Medical Association are: Best-corrected visual acuity in one eye during visual development due to monocular strabismus, uncorrected refractive error and high refractive error, and form deprivation is below the corresponding age visual acuity, (visual acuity below 0.5 for children aged 3 years; below 0.6 for children aged 4 to 5 years; below 0.7 for children aged 6 to 7 years) or The diagnosis of amblyopia should be considered when the visual acuity of both eyes differs by two lines or more.
The sensitive period of visual development is generally considered to be from birth to 4 to 5 years of age.
According to the different causes of amblyopia, there are four types of amblyopia: form deprivation amblyopia, refractive error amblyopia, refractive aberration amblyopia and strabismic amblyopia.
1, form deprivation amblyopia: In infancy, due to ptosis, corneal clouding, congenital cataracts or too long cover-up after eyelid surgery, light stimuli cannot enter the eye, preventing or blocking the macula from receiving form stimuli, thus creating amblyopia.
Refractive amblyopia: It is mostly binocular and occurs in children or adults with hyperopia and astigmatism who do not wear corrective glasses, most of whom have more than 500 degrees of hyperopia and ≥200 degrees of astigmatism or both. The visual acuity of both eyes is equal or similar.
3, refractive parametric amblyopia: because the two eyes do not see the same, the retinal imaging size and clarity of the two eyes are different, the macular imaging of the higher refractive eye is large and blurred, causing insufficient fusion reflex stimulation of the two eyes, can not form binocular monocularity, resulting in passive inhibition, amblyopic eye is often hyperopic, or both eyes are hyperopic, amblyopic eye refractive error is high, the difference between the two eyes refractive spherical diameter 1.5D, astigmatism difference 1D, higher refractive error often forms amblyopia.
4, strabismic amblyopia: occurs in one eye, the child has strabismus or had strabismus, common in children with unilateral strabismus onset under four years of age, its due to the cerebral cortex actively inhibit the visual impulse of the strabismus, long-term inhibition of the formation of amblyopia.
Second, the examination method of amblyopia.
First, routine visual acuity check
Patients need to undergo routine examination of the anterior segment of the eye and the posterior segment of the eye at the time of consultation. In infants and young children, it is especially important to carefully examine the anterior and posterior segments of the eye and, if necessary, to examine the fundus carefully with dilated pupils under sedation such as chloral hydrate to exclude organic lesions.
For children with poor naked eye vision, optometry should be performed to correct visual acuity, including computerized optometry, photometry and subjective interpolation optometry, which is generally based on photometry plus interpolation optometry. If the corrected visual acuity does not reach the normal standard, atropine pupil dilatation optometry should be performed, generally drops of 1% atropine ophthalmic ointment should be applied to the eyes, and the pressure on the lacrimal sac should be applied for 8~10 minutes after the point to prevent it from entering into the nasolacrimal duct, twice a day, and after 3 days, photometry and insertion optometry should be performed again to check the corrected visual acuity.
Amblyopia treatment
1.Treatment principles.
(1) Remove the causes of amblyopia (etiology treatment): such as correction of refractive error, refractive aberration; perform strabismus correction surgery; treat factors that deprive visual development, such as keratoconus, cataract and other diseases as early as possible.
(2) Actively promote the redevelopment and recovery of vision. Amblyopia training.
If the amblyopia is caused by congenital cataract or congenital ptosis, the ptosis should be corrected and cataract surgery should be performed to remove the factors causing the amblyopia; if the amblyopia is caused by refractive factors, the refractive error or refractive aberration should be paralyzed by the ciliary muscle and then different optometry should be performed according to different conditions. The other types of refractive errors will be corrected by subtracting the physiological adjustment. The younger the age, the greater the physiological adjustment.
2. Treatment of amblyopia
Masking and suppression therapy: When the corrected visual acuity of both eyes differs by 2 lines or more on the visual acuity table, the eye with better visual acuity should be covered.
All-day masking is used for moderate or severe amblyopia in one eye, where the difference in visual acuity between the two eyes is significant. The proportion of masking and release is chosen according to the visual acuity of the amblyopic eye and the patient’s age. Depending on the situation, you can choose to cover for 3 days and open for one day or cover for 6 days and open for one day. Generally, the older you are, the worse the visual acuity of the amblyopic eye is and the longer the time you need to cover. Do not cover the amblyopic eye.
Partial masking is used when the difference in vision between the two eyes is not large, the healthy eye can be covered for 4~5 hours a day. For children with a large difference in vision between the two eyes or for children who often “peek”, you can choose eye patches to completely cover the healthy eye. For milder amblyopes and those with good compliance, eye shields can be chosen.
Some school-age children who are reluctant to wear eye shields for fear of ridicule may choose to blur the vision of the healthy eye with a Bangerter patch, which is a translucent membrane with varying densities that allow the healthy eye to see through the membrane to a level lower than that of the amblyopic eye, depending on the need. This forces the amblyopic eye to see.
For children who do not want to cover up, repression therapy can be used. In the healthy eye, 1% atropine ophthalmic ointment is given once or twice a week or the healthy eye is given overcorrective glasses to make the vision of the healthy eye lower than the corrected vision of the amblyopic eye, forcing it to use the amblyopic eye to see. However, the course of treatment is long, complicated and expensive, and the effect is not as good as the masking method.
Prognosis of amblyopia
The prognosis of amblyopia is closely related to the age of amblyopia treatment. 3-6 years old is the critical period of visual development, and the best effect of amblyopia treatment is achieved during this period.