umbrascopy

August 12, 2017 17:50 | Good Vision

Much of my information about the eyes has been obtained by retinoscopy , ieClinical examination of the retina eyes.Retinoscope is a tool for determining D-fraction eyes.With its help in the pupil dropped cougars light reflected from the mirror.The light source can be located outside the tool-top or behind, so the patient and within it (with an electric battery).When viewed through a hole in the mirror physician sees more or less of the pupil filled by the light which in the normal eye has a reddish-yellow color (the color on the retina).If the eye is focused on the point where he examined, inaccurate, sees also a dark shadow at the edge of the pupil.The behavior of this shadow when the mirror moves in different directions, and there is something that shows us the refractive state of the eye.

If the tool is used at a distance of six feet and a shadow moving in the direction opposite to the movement of the mirror, the myopic eye.If the shade is moving in the same direction as the mirror or the hyperopic

eye, or normal.In the case of hyperopia, this movement is more pronounced than in the case of a normal eye, and a specialist can usually distinguish between these two states in one movement only character shadow.With astigmatism, the movement is different in different meridians (meridian is the projection of the plane drawn through the poles of the eye, on the front part. In order to determine the degree of refraction abnormalities correctly distinguish hyperopic eyes of normal, or to distinguish between different types of astigmatism, it is usually necessary to experiment with the lensplaced in front of the patient's eye. If, instead of the flat mirror is used concave, the movements described will be reversed. However, in practice a flat mirror is used more often.

Snellen test card and trial spectacle lenses can be used only under certain favorable conditions. Retinoscope you can usealways and everywhere. it is a little easier to use in dim light than in bright light, but in principle, it can be used in all lighting conditions, even in bright sunlight shining directly into the eye. Petinoskop can also be used under many other unfavorable conditions.

Determination of refraction with the Snellen test card and trial lenses takes a considerable amount of time (minutes to hours).With the retinoscope, however it can be defined in a split second.Previous methods it would be impossible to obtain any information about the refraction, such as a baseball player when he turns the ball at the moment when it hits on it, and at the time after impact.And retinoskoiom fairly easy to determine, normally his vision or is it mystical, hyperopic or astigmatic at the moment when the player is doing these movements.If, however, this marked any errors of refraction, it is possible to accurately determine their degree in the shadow of the speed.

With the card and trial lenses conclusions should be made on the basis of the patient's statements that he sees.But the patient is often so worried and confused during the test, he did not know what he sees, he does not know that improve or impair his vision certain points.Moreover, the severity of feniya is not a reliable indication of the state of refraction.A patient with two diopters of myopia can see two times more than the other with the same error of refraction.Osvedetelstvovanie on the Snellen test is actually entirely subjective, whereas the conclusions drawn on the basis of retinoscope is entirely objective, or in any way depend on the patient's statements.

In short, the definition of refraction using a checklist or trial lenses requires a significant investment of time and may be made only under certain favorable conditions, the results are not always reliable.Meanwhile retinoscope can be used for all kinds of normal and abnormal states eye both human and animals.The results are correctly carried out reginoskopii always depend on the state of refraction of the eye.Proper conduct of retinoscopy means that retinoscope should not be brought nearer to the eye than six feet.Otherwise, the subject will be nervous, the refraction, for reasons which will be discussed later, change that will not give the possibility to spend a significant examination.If we are talking about the animals, the retinoscope it is often necessary to use a much larger distances.

more than 30 years, I use the retinoscope to study the refraction of the eye.With it, I examined the eyes of tens of thousands of students, hundreds of infants and thousands of animals, including cats, dogs, rabbits, cows, birds, horses, turtles, reptiles and fish.I used it when the facilities survey rested and when they were in motion (but also when I moved myself), at the moment of awakening, and when asleep.The observations were made even when the objects of study were under the influence of chloroform or ether.I used the retinoscope in the daytime and at night;at moments, when the subjects were calm and when they are worried;when they tried to make out anything and when did such efforts;when they were lying and when telling the truth;when the eyelids were partly closed, shutting of the pupil;when the pupil has been extended and when it was narrowed down to the size of a pinhead;when the eyes move from side to side, up - down, and in other areas.

this way, I have found many previously unknown facts that completely impossible to be brought into line with the generally accepted views in this area of ​​research.This led me to undertake a series of experiments, of which I have already mentioned.Their results are fully in line with my previous observations, which left me no choice but to reject the entire body of orthodox teaching about accommodation and errors of refraction.