Irregularity of refraction
The theory that refractive anomalies are caused by deformations of the eyeball naturally leads to the conclusion that they represent immutable states and that normal refraction is also a certain permanent state. Since this theory is universally regarded as true, it is not surprising to find that a normal eye is considered a perfect mechanism, which is always in good working order. Regardless of whether the object in question is familiar or unfamiliar to a person, its illumination is sufficient or not enough, the environment is pleasant or unpleasant, and even in the presence of stress or bodily disease it is considered that a normal eye should always have normal refraction and normal vision. In fact, the facts do not correspond to this point of view, and therefore they are conveniently attributed to a lack of ciliary muscle or, if such an explanation does not fit, are generally ignored.
However, when we understand how the shape of the eyeball is regulated by the external muscles and how it responds instantly to their effect, it is easy to see that no refractive state, normal or not, can not be permanent. This conclusion is confirmed by the retinoscope. I observed similar facts long before the experiments mentioned in other articles presented them with a satisfying explanation. For 30 years of studying refraction, I was a little caught by people who could maintain the ideal, that is, without any refraction anomaly, seeing for more than a few minutes in a row, even under the most favorable conditions. Often I observed refractive changes 6 or more times per second. The amplitude of the changes was in the range from 20 diopters of myopia to the normal value of refraction.
Similarly, I did not find a single pair of eyes with a constant or invariable value of the refraction anomaly. In all people with refractive anomalies, often during the day and night, there are moments when their vision becomes normal, and their myopia, hypermetropia or astigmatism completely disappear. The shape of the anomaly can also change - myopia turns even into hypermetropia, and one form of astigmatism passes into another.
Of the several thousand schoolchildren surveyed throughout the year, more than half had normal eyes with perfect vision for a certain time, but none of them had perfect vision in every eye throughout the day. Their sight could be good in the morning and worse in the afternoon or vice versa. Many children could read one checklist, having perfect vision, but could not see well another. Many also could read one letter of the alphabet, but could not identify others of the same size and under similar conditions. The degree of deterioration of vision in such cases lay within a wide range and was from 1/3 to 1/10 or less of the norm. The duration of such a state also varied. Under certain conditions, it could last only a few minutes, under other circumstances it could prevent the student from seeing the board for days, weeks, or even longer than that time. Subjected to this state to such an extent were often all students of the class.
A similar condition was observed in infants. Most researchers find hypermetropia in infants. Some of them found myopia. My own research shows that the refraction of the eyes of infants is constantly changing. So, one child was examined under atropine for 4 days in a row, starting from two hours after birth. In both eyes, a three-percent solution of atropine was injected. Pupils at the same time expanded to the maximum. There were other physiological symptoms of atropine use. The first examination showed a state of mixed astigmatism. On the second day, a complex hypermetropic astigmatism was discovered, and the third was complicated myopic astigmatism. The fourth day of the examination showed normal vision, and the next-myopia. Similar changes were noted in many other cases.
What is true for children and infants is equally true for adults of all ages. People older than 70 years suffer from loss of vision of varying degrees, and in such cases the retinoscope always shows some kind of anomaly of refraction. One 80-year-old man with normal eyes and usually normal vision had periods of vision deterioration that lasted from a few minutes to an hour and more. Retinoscopy at such times always showed myopia at 4 diopters and above.
During sleep, the refractive state of the eye often, if not always, with a deviation from the norm. People whose refraction is normal when they are awake, during sleep, there is myopia, hypermetropia or astigmatism. It may also be that if they have any abnormalities of refraction during wakefulness, they will increase during sleep. This is the reason that people wake up with eyes that are tired more than at any other time, and even with severe headaches. When a person is under the influence of ether or chloroform or for some other reason falls into the unconscious position, refractive anomalies also appear or increase.
When the eye looks at some unfamiliar object, an anomaly of refraction always appears. An example of this is the familiar fatigue of the eyes when looking at pictures or other exhibits in a museum. Children with normal eyes who can clearly read small letters a quarter of an inch tall from ten feet, always have trouble reading unfamiliar notes on the blackboard, even though the letters can be two inches tall. An unfamiliar geographical map or even any geographical map gives the same effect. I have never met a child or teacher who could look at a geographical map from a distance without becoming short-sighted. Gothic script was once blamed for allegedly leading to poor eyesight and the appearance of an imaginary "German" disease. But if a German child tries to read the Latin script, he will immediately become temporarily hypermetropic. Gothic or Greek fonts or Chinese characters will have the same effect on the child and on any other person accustomed to the Latin script. Professor Hermann Kohn from Breslau rejected the idea that the Gothic font is tiring for the eyes. On the contrary, he finds "pleasant after a long reading of a monotonous Latin script, return to our beloved Gothic."Since the Gothic font was more familiar to him than other fonts, he found it less tiring for the eyes. Children, learning to read, write, paint or embroider, always suffer from poor eyesight due to unfamiliar lines or objects with which they have to work.
An unexpected flash of light, a quick or unexpected change of light should most likely lead to a deterioration in the vision of the normal eye, which in some cases lasts for weeks and months.
Noise also serves as a frequent cause of impaired vision of the normal eye. When an unexpected loud sound is heard, all people see indistinctly. Familiar noises do not reduce vision, while strangers always do it. Rural children from quiet schools may suffer from poor vision for a long time after moving to a bustling city. In school they can not cope with studies, because their vision is violated. It would, of course, be an obvious injustice on the part of teachers and others to scold, punish or humiliate such children.
In conditions of physical or mental discomfort such as pain, cough, fever, heat or cold discomfort, depression, anger or excitement, refractive anomalies always appear in the normal eye, and in the eye where they already exist, the anomalies increase.
Because of the inconstancy of the refraction of the eye, many accidents occur. When people are hit on the street by a car or a tram, it often happens because they suffer temporary visual loss. Railway, aviation and marine disasters, deaths during military maneuvers, etc., often occur through the fault of some person suffering from temporary loss of sight.
The same reason explains, to a large extent, the confusion that anybody who deals with this issue in statistics, reflecting the frequency of occurrence of certain refraction anomalies, noted. As far as I understand, it has never been taken into account that the results of such studies strongly depend on the conditions in which they were conducted. You can take the best eyes in the world and check them out so that their owner can not enlist in the army. Conversely, the test can be carried out so that the eyes that have a clearly abnormal original vision, within a few minutes, necessary for verification, will achieve normal vision and will be able to perfectly read the check table.