Optima and pessimum
almost all cases of impaired due to refractive errors of view there is an object or objects that can be seen with normal vision.Such objects I called optima.On the other hand, there are some objects that people with normal eyes and normal vision is usually always see the bad.When viewing them, as shown by the retinoscope, there is some kind of refractive error.Such objects I called pessimum.The object becomes an optimum or pessimum depending on the effect which it produces on the psyche.In some cases, this effect can be easily explained.
For many mothers face their children are optimum, and the face of Person pessimum stranger.One dressmaker always managed without glasses to pass a thin silk thread the needle number 10, although she was forced to wear glasses to sew a button, as it does not see holes in them.She taught dressmaking and children considered stupid because they can not distinguish between a two shades of black.Meanwhile she could pick up a couple of colors without comparison samples.Yet thi
In other cases, especially the brain, making one pessimum object, and the other optimum, it is difficult to explain.It is also impossible to explain this fact, when any object can be the optimum for one eye and another for them to be, or to be optimum at the same time and at the same distance and not to be it in other circumstances.Among these countries optima frequent any one letter in the check table.For example, one of my patients could see the letter "K" on the lines of forty, fifteen and ten, but could not see any other letters on these lines, although most patients because of the simplicity of contours would surely have seen some of them better than thisletter as "K".
pessimum can be as strange and unaccountable as optimums.The letter «V» is so simple in its outlines, that many people are able to see it, although they can not see the other letters on the same line.At the same time, some people can not distinguish it on any distance, although able to read other letters in the same word or the same line of the check table.Others not only can not find the letter «V» in the word, but also to read any combination of it, it pessimum, impairs vision both for himself and for other objects.
Some characters or objects become pessimum only in certain situations.Letter, for example, may be pessimum being located at the end or beginning of a line or supply and not to be it elsewhere.When the patient's attention is drawn to the fact that the letter that is visible in one location of, logically, should be seen as well in other areas, the letter pessimum often ceases to be in any situation.
pessimum like optimum can then disappear, then appear.It may vary depending on the distance and lighting.The object, which is pessimum with moderate light, can stop them to be, if the lighting will increase or decrease.Pessimum at a distance of 20 feet can stop them from being at a distance of two or thirty feet, and any object that is pessimum when viewed directly, can be seen with normal vision in the peripheral field of vision.
For most people, the checklist is pessimum.If you can see it with normal vision, so in this world, you can see almost everything that you want.Patients who can not see the letters on the Snellen test, are often able to see the other objects of the same size and the same distance with normal vision.When treated badly or even invisible at all the letters, or when a person is not aware of their vision, refraction increases.A person can watch on a clean white surface without any refractive error, but if he looks at the lowermost part of the checklist, which he sees as clean as clean and empty surface is always marked existence of any refractive error.If you close the visible letters check table, the result will be the same.In short, pessimum can be letters or objects, the vision of which the person is not conscious.This phenomenon is quite common.
When in the peripheral field of view is visible check table, it can worsen vision for the point, which is directed gaze.For example, a person may be considered a distance piece green wallpaper and see their color as well as close-ups.But if in the neighborhood of the considered area to place the test card, the letters which are seen poorly or not at all visible, the retinyl Osprey can show the presence of refractive errors.As vision improves, the number of letters on the test card, which are pessimum is reduced, and the number of optima increases to as long as all the checklist will not be optimum.
pessimum like an optimum, is a manifestation of psychological processes.It is somehow connected with the effort to see, while the optimum is something that has nothing to do with stress.Pessimum not caused by a specific error of refraction, but it is always some error of refraction.When the voltage drops, it ceases to be pessimum becomes optimum.