New interpretation of amblyopia diagnostic criteria

Abstract: some patients with obvious refractive abnormalities or abnormal eye position may be complicated with congenital fundus lesions, which can be confirmed by fundus endoscopy. However, some young children do not cooperate with fundus endoscopy, which may lead to missed diagnosis of other fundus diseases., In the past ten years, we have always regarded the “amblyopia with far vision ≤ 0.8 and uncorrectable caused by functional factors without obvious organic lesions in the eyes” adopted at the working meeting of the National Children’s amblyopia and strabismus prevention and treatment group in April 1996 as the diagnostic standard of amblyopia. Because the diagnostic standard fails to really reveal the essence of amblyopia, it leads to the expansion of amblyopia diagnosis, so that many healthy children join the ranks of amblyopia and receive long-term amblyopia training, which not only wastes limited public medical resources, but also has a more or less impact on children’s body and mind. Based on the five-year medical textbook Ophthalmology (Seventh Edition, people’s Health Publishing House), this paper interprets the connotation and changes of amblyopia diagnostic criteria. I. comparison of new and old diagnostic criteria ^ 1. The traditional definition of amblyopia ^ those with far vision ≤ 0.8 and uncorrectable caused by functional factors without obvious organic lesions in the eye are classified as amblyopia. Key points of diagnosis: (1) no obvious organic lesions in the eyes; (2) corrected visual acuity ≤ 0.8. 2. The latest definition of amblyopia is abnormal visual experience during visual development (monocular strabismus, anisometropia, high refractive error and form deprivation) caused by monocular or binocular best corrected visual acuity decline, and there are no organic lesions in eye examination. Key points of diagnosis: (1) it occurs during visual development; (2) there is abnormal visual experience; (3) best corrected visual acuity decline; (4) There were no organic lesions in ocular examination. 3. Changes of new diagnostic criteria (1) Pay attention to the relationship between corrected visual acuity and age} the new standard pays more attention to the difference of visual development, and fully takes into account the existence of insufficient visual education or growth retardation of young children. Children whose corrected visual acuity does not reach 0.9 but is higher than the lower limit of normal visual acuity of this age group are listed as suspicious objects, closely observed and not included in “amblyopia” Category. This can avoid the expansion of amblyopia diagnosis and the resulting over treatment. (2) pay attention to the role of “abnormal visual experience” in diagnosis. “Abnormal visual experience” actually refers to the cause of amblyopia (risk factors for disease occurrence), mainly including monocular strabismus, anisometropia, high refractive error and form deprivation. In the new standard, the proposed “amblyopia” It is suggested to actively look for abnormal visual experience (risk factors) causing amblyopia. For cases without the above “abnormal visual experience”, further examination should be carried out to eliminate the possibility of visual path lesions, intracranial lesions, hysteria or false low vision, rather than hastily “amblyopia” Diagnosis. Some patients with visual path or intracranial lesions may have abnormal vision, while patients generally have no organic lesions in the eyes. According to the traditional diagnostic criteria, they are included in the category of “amblyopia”, resulting in missed diagnosis of important diseases and delayed treatment. In clinic, some cases with low vision will be encountered. If the auxiliary examination (such as eye electrophysiology, skull CT, etc.) fails to find the lesion, it is usually called “congenital amblyopia” or amblyopia of unknown cause. However, in recent years, clinical and research have found that such patients may have low vision caused by hysteria, pseudo low vision or some diseases we do not know. Therefore, for such patients, many scholars tend to “follow up closely” rather than include the diagnosis of “amblyopia”. II. Diagnostic criteria of amblyopia: 1. The period of amblyopia: during the period of visual development (diagnostic condition I). The sensitive period of 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 amblyopia. In other words, the vision development of patients after the age of 10 ~ 12 is “mature”, and the new “abnormal visual experience” will not lead to the occurrence of “amblyopia”. Therefore, in clinical practice, for cases with corrected visual acuity, If there is evidence of normal vision in the past (vision examination records, etc.), the diagnosis of “amblyopia” should not be established, and other causes of abnormal vision should be actively sought. 2. Abnormal visual experience (diagnostic condition II) “abnormal visual experience” refers to the cause of “amblyopia” (i.e. risk factors of disease occurrence), mainly including: 1) monocular strabismus: it is one of the most common causes of amblyopia. Due to the inhibitory effect of gaze on strabismus, amblyopia occurs. In alternating strabismus, the macula of both eyes has equal opportunities to obtain visual information, which generally does not cause amblyopia. 2) anisometropia is due to the flexion of both eyes Anisometropia is large, the size and clarity of the object image formed by macula are different, and form deprivation exists in the eye with large diopter, resulting in anisometropic amblyopia. The difference between two spherical lenses is 1.50D, and the difference between cylindrical lenses is 1.00d, which can make one eye with higher diopter form amblyopia. 3) high refractive error a: moderate High hyperopia: hyperopia above 4.50ds (overt hyperopia + 2.00ds ~ + 3.00ds) may cause amblyopia, and the severity of amblyopia is positively correlated with the degree of hyperopia. B: ultra high myopia: Patients with medium and low myopia generally do not cause amblyopia because the affected eye can receive close-up visual information. Only ultra-high myopia above -8.00ds ~ -10.0ds is the risk factor for amblyopia. C : astigmatism: astigmatism above 2.00dc can cause amblyopia. Amblyopia caused by ametropia is a common type, among which hyperopia astigmatism is the most common. The common degree is hyperopia astigmatism > high hyperopia > moderate hyperopia > ultra-high myopia.     4)、 Form deprivation usually occurs in refractive interstitial opacity (such as congenital cataract, corneal opacity), ptosis, iatrogenic eye shading, etc. amblyopia is formed due to the lack of form sensory stimulation, which deprives the macula of the opportunity to form a clear image. The study found that infants and young children can form irreversible amblyopia even if they are improperly covered with monocular for 3-7 days, which should attract the attention of ophthalmologists and relevant personnel. 3. Low corrected visual acuity In normal children of the same age (diagnostic condition III) 1). Corrected visual acuity and correction methods: 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 with frame glasses)), rather than the vision of unconventional correction methods such as comprehensive optometry or RGP, and the latter two do not represent the daily actual vision. 2) non fixed value of corrected visual acuity: 0.8 is no longer the only standard for the diagnosis of amblyopia, and the existence of insufficient visual acuity or growth retardation of young children should be fully considered, The age of infants and the lower limit of normal visual acuity are shown in the following table: Table 1 lower limit of visual acuity reference value of infants , age , lower limit of visual acuity reference value , 3 years , 0.5 , 4-5 years , 0.6 , 6-7 years , 0.7 , over 7 years , 0, Less common. If the binocular vision is 5.3 and 5.0 respectively, the possibility of amblyopia should also be considered in 5.0 eyes. 4. No organic lesions in the eyes (diagnostic condition IV) no obvious organic lesions in the eyes should be understood as no obvious organic lesions in the eyeball, retrobulbar visual pathway and intracranial visual center. The examination of ocular refractive media and fundus is relatively simple, which is a necessary item for the diagnosis of amblyopia. However, whether there are lesions in the visual path and intracranial often needs unconventional auxiliary examinations such as VEP, visual field and skull CT. Generally speaking, if conditions I – III are met and no abnormality is found in the eyeball examination, the diagnosis is basically clear, and there is no need to further check the head CT, etc. And for suspicious cases (if there is no obvious abnormal visual experience), it is necessary to consider whether other relevant examinations are required according to the specific situation. III. ideas for amblyopia diagnosis. The following table is the conditions that amblyopia diagnosis needs to meet, which is also our clinical diagnosis ideas and process: the clear amblyopia diagnosis requirements are that all conditions I, III and IV meet, and one or more of conditions II meet. Otherwise, it is not recommended to be diagnosed If it is judged as “amblyopia”, especially those with low corrected vision who lack corresponding “abnormal visual experience”, other reasons should be further found. IV. several factors supporting the diagnosis of amblyopia. 1. Crowding phenomenon. Crowding phenomenon refers to that in the refractive correction of amblyopia patients, the corrected visual acuity of single visual target is 1-3 lines better than that of the whole line, It is mainly manifested in that the corrected visual acuity of the comprehensive optometer (generally with a single visual standard) is better than that of the plug-in Optometry (generally using a fixed light box visual acuity chart). This is the clinical feature of amblyopia patients. On the contrary, the existence of “crowding phenomenon” is one of the supporting factors for the diagnosis of “amblyopia”. 2. Diagnostic treatment {for some suspicious objects of amblyopia (the diagnosis is not clear and other diagnoses are excluded, such as unexplained amblyopia). Generally, diagnostic treatment will be carried out according to the treatment standard of amblyopia, and close follow-up will be carried out. If the treatment is effective, it supports the diagnosis of amblyopia. On the contrary, it is necessary to change the diagnosis idea and find other causes of low vision. V. precautions for amblyopia diagnosis. 1. Combined with other diseases Change: some patients with obvious refractive abnormalities or abnormal eye position may be complicated with congenital fundus lesions, which can be confirmed by fundus endoscopy. However, some young children do not cooperate with fundus endoscopy, which may lead to missed diagnosis of other fundus diseases. 2. Is there “congenital amblyopia”? In some books, amblyopia of unknown cause is classified into the category of “congenital amblyopia”. The author believes that before the diagnosis of “congenital amblyopia”, we should first clarify two questions: (1) when did low vision begin to occur? (2) how long did the state of low vision last and whether there was any change? The possibility of “congenital amblyopia” can be considered only if the condition of “low vision” occurs from an early age and there is no obvious change after a long follow-up. In clinic, because young children can not describe the exact time of poor vision, it brings some confusion to the diagnosis. And because these patients have no “abnormal visual experience” causing amblyopia, it is likely that there are other causes we have not yet known, which can be listed as “suspicious objects of amblyopia” and followed up closely. Amblyopia is a common eye disease in children. If it is not treated in time, it will have a great impact on the study and employment of patients. With a large number of publicity reports in recent years, patients’ parents, ophthalmologists and relevant health care doctors pay more and more attention to amblyopia, but the subsequent generalization of diagnosis and excessive treatment lead to the waste of public medical resources, increase the economic and spiritual burden of patients’ families, and even bring harm to children’s physical and mental health. Therefore, as the front-line personnel of children’s eye health care, we should seriously study and experience the criteria of amblyopia diagnosis, make our diagnosis “off” and reduce misdiagnosis and missed diagnosis.