Dear students
Don't play the game brush vibrato
Relax after a holiday
You raise your eyes
Has the world seen change?
To avoid such a situation
Prevent vision loss
and the risk of myopia
First of all, start with understanding myopia related knowledge -
Recently, the Ministry of Education issued a notice to deploy the main information reporting of vision monitoring for primary and secondary school students in the spring semester of 2022. Also published with the document is an excerpt from the Guidelines for Appropriate Techniques for the Prevention and Control of Myopia in Children and Adolescents (Updated Edition). Based on the excerpts, 8 "knowledge cards" were made, let's take a look at it together-
vision
Also known as visual resolution, it is the ability of the eye to distinguish the minimum distance between two external objects.
Vision is with the refractive system and retina development gradually mature, 0 to 6 years old is the key period of children's vision development, newborns are born with only a sense of light, 1 year old vision is generally up to 4.3 (standard logarithmic vision table, the same below), 2 years old vision is generally up to 4.6 or more, 3 years old vision is generally up to 4.7 or more, 4 years old vision is generally up to 4.8 or more, 5 years old and above vision is generally up to 4.9 or more.
Face up to the process of transformation
Children's eyeballs and vision are gradually mature, newborns have smaller eyeballs, shorter eye shafts, and farsightedness in both eyes.
Childhood and adolescence is the fastest stage of eye refractive change, and its development law is manifested as as children grow and develop, the eyeball gradually grows, the eye axis becomes longer, and the degree of farsightedness gradually decreases and tends to face up, which is called "the process of orthodonization".
Ideally, children do not develop from farsighted to orthopic eyes until they are 12 years old.
Farsighted reserves
The farsightedness before the normalization is mostly physiological farsightedness, which is a kind of "farsighted reserve", which can be understood as "confrontation" and develops into a "buffer zone" for myopia.
Insufficient hyperopia reserve means that the naked eye has normal visual acuity, and although the refractive state after mydriasis refraction does not meet the myopia standard, the degree of hyperopia is lower than the physiological value range of the corresponding age group.
If the physiological refractive index of children aged 4 to 5 years is 150 to 200 degrees of hyperopia, there is a reserve of 150 to 200 degrees of farsightedness, if the physiological refractive index of children of this age is only 50 degrees of farsightedness, it means that their hyperopia reserve is consumed too much, and it is possible to appear myopia earlier.
Naked eye vision
Also known as uncorrected vision, refers to vision that has not been corrected by any optical lens, including naked-eye far vision and naked-eye near-vision.
diopter
The unit of the refractive phenomenon size (refractive force), expressed in D.
The refractive system of parallel rays passing through the eye is concentrated at a focal length of 1 m, and the refractive force of the eye is 1 diopter or 1.00 D.
Diopter is usually reflected by the degree of the glasses, and the value of diopter D multiplied by 100 is the degree, for example, the diopter of a myopic lens at 200 degrees is -2.00 D, and the diopter of a 150 degree farsighted mirror is +1.50 D.
myopia
A type of refractive error refers to the pathological state of the human eye in the state of adjustment and relaxation, and the parallel light rays are focused on the retina after passing through the refractive system of the eyeball, which is manifested by decreased vision in the distance.
Screening myopia
Fast and easy methods such as telesighted examination, non-ciliary muscle paralysis (commonly known as computer refraction) or cross-examination are used to screen out those who may have myopia in children and adolescents.
When the naked-eye far vision < 5.0 in children and adolescents over 6 years of age, the equivalent spherical lens (SE) ≤-0.50 D is judged as screening myopia by computer refraction under non-ciliary muscle paralysis.
Equivalent spherical mirrors
Equivalent spherical degree (SE) = spherical degree + 1/2-column degree.
If a student has a spherical degree of +0.50 D and a cylindrical degree of -3.00 D, the student's SE= +0.50 +1/2 (-3.00) = -1.00 D, which is equivalent to -1.00D myopia.
How is the eye chart used?
How is vision counted?
Read on
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Standard logarithmic eye chart
(GB11533—2011) Excerpt
5 How to use the eye chart
5.4 Vision measurement
5.4.1 General vision measurement
According to the general use method of the eye chart, the smallest line of visual targets that can be recognized by the examined eye is measured (the number of correct visual targets recognized should exceed half of the total number of visual targets in the row), and the visual record value of the line visual target is recorded, that is, the vision of the eye.
5.4.3 Low vision measurement
When the visual acuity is less than 4.0 (0.1), the following methods can be used:
a) The subject goes directly to the front 1m of the far vision chart, and the measured 5 points of the record need to subtract the correction value of 0.7 (that is, the corresponding correction value of the 1m inspection distance in table 5 is e), at this time, the far vision table can measure 3.3-4.6 (0.02-0.4) of vision;
b) When the subject approaches the far-sightedness chart to a certain inspection distance listed on the left side of Table 5, the measured 5-point record value plus the corresponding correction value e is his actual vision;
6 Vision statistics
6.1 Visual acuity recorded with 5 points can be directly compared with visual acuity level and statistical treatment of visual average, standard deviation, standard error, significance test and so on.
6.2 All decimal records, fractional records and viewing angles, visual target size, design distance and other values cannot be directly compared and counted using the 6.1 method, and the decimal records can be converted into statistics in Table 8.
Source: Inner Mongolia Education Release