Uncovering the "hot air balloon" in eye examinations: A complete guide to children's vision care

Author: Qian Chen Children's Hospital Affiliated to Fudan University

Reviewer: Zhou Xiaohong, deputy chief physician, Children's Hospital Affiliated to Fudan University

Four-and-a-half-year-old Nan Nan was found to have abnormal eye refraction during a physical examination at kindergarten, so his mother brought him to the ophthalmology department for treatment. After a series of procedures including online appointment, hospital visit, and consultation, Nan Nan excitedly pointed at the instrument and said to his mother, "Balloon, balloon, there is a balloon here." Hearing the child's words, I realized that Nan Nan was looking at the fixation icon in the instrument.

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This hot air balloon that seems to be floating in the distant sky is actually a fixation icon in the computer ophthalmometer, which is used to guide the eye's gaze. Different brands of computer ophthalmometers may use different fixation icons, among which hot air balloons and red houses are the most common.

"Great kid, open your eyes wide and look at the hot air balloon inside." The optometrist encouraged the child to concentrate while quickly and accurately adjusting the focus to make the measuring ring clear. Based on the infrared imaging in the eye, the computer ophthalmometer will print out an optometry form showing the preliminary optometry results. The subsequent examination results of the child's eye axis, eye position, and vision will be combined to preliminarily determine the dynamic refractive state of the eye under small pupils.

The hot air balloon icon has two main functions:

1. In a blurry state, use the "fog vision method". At this time, a convex lens will be placed in the window of the computer ophthalmometer to blur the vision, thereby relaxing the eyes and allowing the eyes to prepare for the eye test in a relaxed and natural state, and try to eliminate interference with the eye's adjustment function.

2. When the image becomes clear, the hot air balloon icon in the screen window can fix the line of sight, guide the examined child to stare and look straight ahead, improve concentration, and thus obtain more accurate optometry data.

Pay special attention to the following three points:

1. Never give your child glasses based solely on a computer optometry sheet. Since children's eye accommodation function is strong, the blur-clear changes during computer optometry cannot ensure that the eyes are completely relaxed. Therefore, it is very necessary to follow the doctor's advice to perform mydriasis optometry, which is harmless to the eyes. Mydriasis drugs can paralyze the ciliary muscles of the eye, so that the optometry results are not affected by accommodation factors. Optometrists will measure the true and accurate refraction by combining objective retinoscopy and subjective optometry. Therefore, the data measured by the computer ophthalmometer is only a reference value and cannot represent the precise refractive state of children.

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2. Children's eye examination and glasses fitting is a corrective behavior, and a prescription can only be given after a comprehensive evaluation. For young children, patients with excessive eye accommodation, abnormal vision, poor cooperation, and nystagmus, the value obtained only through computer optometry is a dynamic refractive state, which will change with the accommodation state and often deviate from the actual refractive power. The doctor will combine the results of other ophthalmic examinations, comprehensively consider the child's age, eye position, eye axis, visual function, and refractive power and corrected vision before and after mydriasis, to determine whether there is refractive error and whether glasses are needed or other corrective measures are taken.

3. Parents should take their children to regular medical institutions for eye examinations regularly. Premature babies, children with a family history of myopia, infants and young children with abnormal refractive indexes during physical examinations, and children aged 2 and above need regular professional eye examinations.

❀ Pay attention to children's eye care and build health big data

In view of the characteristics of infants and young children, professional vision examinations are performed using vision screening devices as well as graphic eye charts suitable for young children or children with poor cooperation, digital sight marks, and conventional E-shaped eye charts to provide babies with a more comprehensive eye health assessment.

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