With the increasing clinical use of anticoagulant and antiplatelet drugs and the increase in the average age of patients undergoing ophthalmic surgery, the impact of these drugs on ophthalmic surgery is receiving increasing attention from ophthalmologists. Recently, a review was published in Br J Ophthalmol by Professor Kong et al. in the UK.
Amblyopia diagnostic criteria.
1. Period of amblyopia occurrence: within the period of visual development (diagnostic condition I).
The sensitive period for children’s visual development is 0-12 years old, and the critical period is 0-3 years old. Various abnormal visual experiences during this period (before visual maturity) can lead to the occurrence of amblyopia. In other words, after the age of 10 to 12 years, the patient’s visual development is generally “mature” and new “abnormal visual experiences” do not lead to “amblyopia”. Therefore, in clinical cases with abnormal corrected visual acuity, if there is evidence of previous normal visual acuity (visual acuity examination records, etc.), the diagnosis of “amblyopia” should not be valid and other causes of abnormal visual acuity should be actively sought.
2. Abnormal visual experience (diagnostic condition II)
”Abnormal visual experience” refers to the cause of amblyopia (i.e. risk factors for the development of the disease), mainly including
(1) Monocular strabismus: It is one of the most common causes of amblyopia, which is caused by the suppression of the strabismic eye by the gaze eye. In alternating strabismus, both eyes have equal access to visual information, which generally does not cause amblyopia.
(2) Refractive aberration: Due to the large refractive aberration between the two eyes, the macula forms objects of unequal size and clarity, and there is a form deprivation in the eye with larger refractive power, leading to the occurrence of refractive aberration amblyopia. The difference between the two eyes is 1.50D in the spherical lens and 1.00D in the column lens, which can cause amblyopia to form in one eye with higher refraction.
(3) High refraction: moderate and high hyperopia: hyperopia of 4.50DS or more (dominant hyperopia +2.00DS to +3.00DS) may cause amblyopia, and the severity of amblyopia is positively related to the degree of hyperopia.
Ultrahigh myopia: Patients with low to moderate myopia, because the affected eye can receive visual information at close range, generally do not cause amblyopia.
Astigmatism: Astigmatism above 2.00DC can cause amblyopia. Amblyopia caused by refractive error is the more common type, among which hyperopic astigmatism is the most common, and the common degree: hyperopic astigmatism > high hyperopia > moderate hyperopia > ultra-high myopia.
(4) Formal deprivation: Most often occurs in cases of refractive interstitial clouding (e.g., congenital cataract, corneal clouding), ptosis, and medically induced eye shielding. Amblyopia is formed when the macula is deprived of the opportunity to form clear images due to insufficient form stimulation. Studies have found that even 3-7 days of inappropriate monocular masking in infants and children can lead to irreversible amblyopia, which should be brought to the attention of ophthalmologists and related personnel.
3.Corrected visual acuity is lower than normal children of the same age (diagnostic condition III)
(1) Corrected visual acuity and correction method: The visual acuity in the amblyopia diagnostic criteria is “corrected visual acuity”, and it is the corrected visual acuity of ordinary optometry (such as the visual acuity of wearing frame glasses), not the visual acuity of unconventional correction methods such as comprehensive optometry or RGP, which do not represent the actual daily visual acuity.
(2) Corrected visual acuity is not a fixed value: 0.8 is no longer used as the only criterion for amblyopia diagnosis, and the presence of under-parented or delayed vision in younger children needs to be fully taken into account. The lower limits of age and normal visual acuity for infants and children are listed below.
(3) The difference between the two eyes is more than two lines: this is a relatively special case and is less common. If the visual acuity of both eyes is 5.3 and 5.0 respectively, the possibility of amblyopia should also be considered in 5.0 eyes.
4.No organic lesion in the eye (diagnostic condition Ⅳ)
The absence of significant organic pathology in the eye should be understood as the absence of significant organic pathology in the eye, the posterior visual pathway and the intracranial visual center.
The refractive media and fundus examination are relatively simple and are mandatory for the diagnosis of amblyopia, but the presence of lesions in the optic pathway and intracranial area often requires non-conventional ancillary examinations such as VEP, visual field and cranial CT to be clarified. Generally speaking, for those who meet conditions I-III and no abnormalities are seen in the eye examination, the diagnosis is basically clear and no further investigation of cranial CT is needed. For suspicious cases (e.g., no obvious abnormal visual experience), it is necessary to consider whether other relevant examinations are needed according to the specific situation.
Ideas for the diagnosis of amblyopia
The following table shows the conditions that need to be met for the diagnosis of amblyopia, which is also our clinical diagnostic philosophy and process: A clear diagnosis of amblyopia requires that all conditions I, III and IV are met, and one or more of II are met. Otherwise, the diagnosis of amblyopia should not be made, especially for those with low corrected visual acuity who lack the corresponding “abnormal visual experience”, and other causes should be further investigated.
Several factors support the diagnosis of amblyopia
1. Crowding phenomenon
Crowding phenomenon refers to the refractive correction of amblyopic patients, the corrected visual acuity of single vision marker is 1-3 lines better than the whole line of vision marker, mainly in the comprehensive optometry (usually with single vision marker) corrected visual acuity is better than the insert optometry (usually using a fixed light box visual acuity table) corrected visual acuity. This is a clinical characteristic of amblyopic patients, in turn, the presence of “crowding phenomenon” is one of the supporting factors for the diagnosis of “amblyopia”.
2. Diagnostic treatment
In some cases of amblyopia (where the diagnosis is unclear and other diagnoses are ruled out, such as amblyopia of unknown origin), diagnostic treatment is generally provided in accordance with the criteria for the treatment of amblyopia, with close follow-up. If the treatment is effective, the diagnosis of amblyopia is supported, and if not, the diagnosis needs to be changed to look for other causes of low vision.
Notes for amblyopia diagnosis
1. Combination of other pathologies.
Some patients with obvious refractive abnormalities or eye position abnormalities may have combined congenital fundus lesions, which can generally be clarified by fundoscopic examination. However, because some younger children do not cooperate with fundoscopic examination, other fundus diseases may be missed.
2. Is there a “congenital amblyopia”?
In some books, unexplained amblyopia is categorized as “congenital amblyopia”. The author believes that before making a diagnosis of “congenital amblyopia”, two issues should be clarified.
(1) When did the hypotropia start to occur?
(2) How long has the low vision lasted and has it changed? The possibility of “congenital amblyopia” can only be considered if the “low vision” condition has been present since childhood and has not changed significantly over a long period of follow-up. In clinical practice, the diagnosis is confusing because young children are unable to describe the exact time of poor visual acuity. In addition, since these patients do not have the “abnormal visual experience” that causes amblyopia, it is likely that other causes exist that are not yet recognized, and they can be classified as “amblyopic suspects” and followed closely.
Amblyopia is a common childhood eye disease that, if left untreated, will have a great impact on the patient’s learning and employment. With a lot of publicity in recent years, parents, ophthalmologists and related health care doctors are paying more and more attention to amblyopia, but the consequent generalization of diagnosis and overtreatment lead to the waste of public medical resources, increase the financial and mental burden of patients’ families, and even bring physical and mental harm to the affected children. Therefore, as front-line personnel in children’s eye care, we should learn and appreciate the criteria of amblyopia diagnosis, so that we can make a good diagnosis and reduce misdiagnosis and missed diagnosis.
Amblyopia treatment methods
Eliminate inhibition, improve visual acuity, correct eye position, train macular fixation and fusion function, in order to restore the visual function of both eyes.
1.Optical correction: Almost all amblyopic patients are combined with refractive error, and the direct cause of amblyopia in refractive amblyopia and refractive aberration amblyopia is refractive error. The presence of refractive error can lead to blurred retinal imaging or suppression of the healthy eye. Therefore, optical lenses, contact lenses, or refractive surgery are used to first clarify the retinal image of the amblyopic eye and lay the imaging foundation for visual development. The prerequisite for optical correction is accurate optometry.
Patients with amblyopia are required to obtain a static, accurate optometric result by paralyzing the eye’s accommodation with a dilating agent. Then, based on the patient’s refractive error data obtained from the dilated eye exam and the different types of refractive errors, fitting data is obtained by trial lenses after pupil retraction. For all patients with amblyopia, who are clearly examined for refractive error, it is necessary to keep the glasses on constantly and not to take them off and on to ensure good eye adaptation to the lenses and a stable optical correction. The pupil should be dilated with 1% atropine eye drops or eye ointment, and the fundus should be checked for lesions before a detailed optometry is done to determine the degree of refractive error, and those with hyperopia or hyperopic astigmatism should be given glasses for correction. Many strabismus wear glasses for a period of time, the eyes are not slanted, or the strabismus degree is significantly reduced. For such a child, we should encourage him to insist on wearing glasses, look far and near to wear, not to interrupt, generally insist on wearing about six months to see the effect. After wearing the glasses should be every 1 year optometry 1, in order to grow with the age, adjust the glasses degree.
2. Covering: Covering and optical correction are called the cornerstones of amblyopia treatment methods. Especially for amblyopic patients with inconsistent amblyopia in both eyes, the scientific nature of the masking program and the degree of implementation play an absolute role in the effectiveness of amblyopia treatment. The most common method of masking is to cover the healthy eye (the one with better vision).
With the masking and visual deprivation of the healthy eye, the poor eye is able to gain visual perception and visual afferent opportunities, thus the poor eye is exercised and excited. Masking needs to be combined with the condition and age. For example, for amblyopes younger than 3 years old, it is generally not recommended to cover more than 6 hours per day in one eye, and monitoring of visual acuity in the healthy eye is needed to prevent masking amblyopia. In cases where the amblyopia is close in both eyes, alternate masking is sometimes used. This means that the two eyes are covered alternately, so that the open eye is given alternate opportunities for visual exercise. In cases where strabismus is present, alternate masking becomes necessary.
The masking plan should also take into account the patient’s visual acuity and psychological status. For example, in patients with extremely low corrected visual acuity in one eye, after covering the healthy eye, the vision of the open poor eye cannot meet the requirements of daily walking and sports, learning, and even eating and dressing activities, so it is necessary to gradually extend the duration of coverage; for example, in older amblyopic patients, covering one eye during the day has a great impact on the appearance, so in order to take into account the patient’s psychological state and social activities, a short coverage program can be developed –The amblyopic patient is covered at home, alone or on rest days, and both eyes are open when going out and at school.
For some patients who do not cooperate with masking because they are afraid of ugliness, trouble, or difficulty with sports, medication or optical suppression can be used as a partial or complete alternative to traditional masking. Sometimes, it is necessary to cover the poor eye to correct the paracentral gaze, i.e., inversion masking.
3. Suppression therapy: The principle is to use overcorrected or undercorrected lenses and daily atropine drops to suppress the function of the primary eye, while the amblyopic eye wears normal corrected lenses for distance viewing or overcorrected lenses for near viewing.
(1) Suppression of near vision in the healthy eye: 1% atropine solution daily in the healthy eye, corrective eyeglasses, and 2.00 or 3.00 spherical lenses on top of corrective lenses in the amblyopic eye, which forces the patient to look far away in the healthy eye and near in the amblyopic eye.
(2) Suppression of distance in the dominant eye: the dominant eye wears atropine drops and overcorrective lenses with 3.00 spherical lenses to make it difficult to see far, but to see near; the amblyopic eye wears all corrective lenses to see far.
(3) Complete suppression: the primary eye wears undercorrected lenses with atropine drops, usually minus 5.00 spherical lenses available or minus positive lenses; the amblyopic eye wears corrective lenses. This allows the primary eye to see neither near nor far.
(4) Selective depression.
For over-regulated pooling: atropine drops in the primary eye, corrective lenses in the amblyopic eye, and bifocal lenses in the amblyopic eye to promote near viewing and to reduce or eliminate the internal obliquity in near viewing.
Maintenance and consolidation: alternate suppression of both eyes. Atropine was discontinued in the primary eye and two pairs of glasses were prescribed, one pair of overcorrected 3.00 spherical lenses in the right eye and one pair of overcorrected 3.00 spherical lenses in the left eye.
3.00, alternating between these two pairs of glasses on alternate days. The child sees far with the right eye one day and far with the left eye every other day to prevent recurrence of amblyopia.
4, after image therapy: is the correction of paracentric gaze, improve vision method, the use of protection of the central recess of the fundus, with 3o, 5o, 7o round black dot after image mirror, 6V15W strong light shine macular area, so that it produces after image, suppress paracentric gaze, excite the central vision function, at this time to look at the cross or visual acuity table can see the E word, twice a day, each time repeatedly do 2 ~ 3 times.
5, fine visual training: the use of beads, needle, illustration, tracing, training chess cover healthy eyes and other products for fine visual training can consciously force the amblyopic eye to focus on a small target, so that its amblyopic eyes are inhibited photoreceptor cells are stimulated to lift the inhibition, so as to improve visual acuity.
6, red filter method: the macular area of the fundus contains only cone cells, cone cells are sensitive to red light, forcing the central concave gaze, inhibit the paracentral area, there are many such treatment instruments in China, the filter wavelength is 620 ~ 700nm, raw minutes flashing 60 ~ 80 times is appropriate.
7, drug therapy: drug therapy is generally through eating, paste, coating and other methods of ingestion of some drugs beneficial to the eyes, so as to relieve visual fatigue and improve vision.
8.Food therapy: pay more attention to the nutrition of amblyopic children, if necessary, supplement some vitamin B1, vitamin B12, vitamin C, cod liver oil and zinc, iron, calcium, etc.. In addition, it is best not to let children eat overcooked protein-based food, so as to ensure that children have balanced nutrition.
9, Chinese medicine: Chinese medicine is generally through the massage of acupuncture points around the eyes to relieve eye fatigue and promote blood flow in the eyes, so as to improve vision.
10, binocular vision training: For amblyopic patients with combined binocular visual impairment. Completing augmented amblyopia training and achieving corrected visual acuity of 1.0 or higher in both eyes is not the end point of amblyopia treatment. For example, the three most common types of amblyopia with combined binocular visual impairment are: strabismic amblyopia, refractive parallax amblyopia, and amblyopia with low initial visual acuity in both eyes. When a patient with amblyopia has corrected visual acuity above 0.6 in both eyes and has simultaneous perception, he or she can do binocular vision training. It is time to do binocular vision training. Binocular vision training can be roughly divided into three stages: simultaneous vision training, fusion training and stereo vision training. These three stages can be subdivided into targeted training to overcome visual dysfunction. Patients with amblyopia with a combined permanent strabismus should have surgery to correct the strabismus after the corrected visual acuity is close to normal, and do binocular vision training after surgery.
11.Consolidation amblyopia treatment: After the visual acuity reaches the normal value (more than 1.0 in decimal method and more than 5.0 in logarithmic method) and the binocular vision is sound, it is not the end point of amblyopia treatment. Stable achievement of the above criteria is the standard of amblyopia treatment. The Chinese Medical Association’s criteria for complete cure of amblyopia (established in 1987) are: corrected visual acuity greater than or equal to 0.9, stereo acuity less than or equal to 60″, and stability for more than three years