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Refraction Study
Last reviewed: 23.04.2024
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The study of refraction in children has a number of characteristics. First, it is not always possible to give a subjective assessment of vision, and secondly, the influence of the habitual tonus of accommodation determines the determination of different refractions in natural conditions and with drug paresis of accommodation (cycloplegia). Until recently, only the reliable cycloplegic agent was considered atropine. In our country, till now, for standard cycloplegia, a 3-day (2 times a day) instillation of atropine into the conjunctival sac is taken. The concentration of the solution depends on the age: up to 1 year - 0.1%, up to 3 years - 0.3%, up to 7 years - 0.5%, over 7 years - 1%. Negative moments of atropinization are well known: the possibility of general intoxication, as well as a long accommodation cutoff. At present, for the induction of cycloplegia, short-term agents are increasingly used: 1% cyclopentolate (cyclomed) and 0.5-1% tropicamide (midriacil). Cyclopentolate in the depth of cycloplegic action is close to atropine, tropicamide is much weaker, for the study of refraction in children it is rarely used.
For the study of refraction in children, mainly objective methods are used. The oldest of them, but still not lost value, is a skyscopy with a flat mirror. Children 3 years and older also use automatic refractometry. Subjective examination of refraction (determination of the optical power of a lens with which the highest visual acuity is possible) is usually carried out from 3 years. At the same time, it is first determined by silhouette pictures, and later by tests "E", Landolt's rings and letters.
The magnitude of visual acuity in children without eye pathology can vary widely. Conditionally lower limit of normal visual acuity at the age of 3 years can be considered 0.6, at the age of 6 years - 0.8. Much more important for the detection of eye pathology is not the same reduction in visual acuity of both eyes, and its difference on two eyes. The difference in the monocular visual acuity between the eyes is already 0.1-0.2 should be alarming, in these cases an in-depth examination is necessary.
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