Optimums and Pessimums. - Better Eyesight, December 1919, Editor: W.H. Bates, M.D.

Discussion in 'Optometry Archives' started by Zetsu, Jun 13, 2009.

  1. Zetsu

    Zetsu Guest

    [...]

    In nearly all cases of imperfect sight due to errors of refraction
    there is some object, or objects, which can be regarded with normal
    vision. Such objects I have called optimums. On the other hand, there
    are some objects which persons with normal sight always see
    imperfectly, an error of refraction being produced when they are
    regarded, as demonstrated by the retinoscope. Such objects I have
    called pessimums. An object becomes an optimum, or a pessimum,
    according to the effect it produces upon the mind, and in some cases
    this effect is easily accounted for.

    For many children their mother's face is an optimum, and the face of a
    stranger a pessimum. A dressmaker was always able to thread a No. 10
    needle with a fine thread of silk without glasses, although she had to
    put on glasses to sew on buttons, because she could not see the holes.
    She was a teacher of dressmaking, and thought the children stupid
    because they could not tell the difference between two different
    shades of black. She could match colors without comparing the samples.
    Yet she could not see a black line in a photographic copy of the Bible
    which was no finer than a silk of thread, and she could not remember a
    black period. An employee in a cooperage factory, who had been engaged
    for years in picking out defective barrels as they went rapidly past
    him on an inclined plane, was able to continue his work after his
    sight for most other objects had become very defective, while persons
    with much better sight for the Snellen test card were unable to detect
    the defective barrels. The familiarity of these various objects made
    it possible for the subjects to look at them without strain - that is,
    without trying to see them. Therefore the barrels were to the cooper
    optimums; while the needle's eye and colors of silk and fabrics were
    optimums to the dressmaker. Unfamiliar objects, on the contrary, are
    always pessimums.

    In other cases there is no accounting for the idiosyncracy of the mind
    which makes one object a pessimum and another an optimum. It is also
    impossible to account for the fact that an object may be an optimum
    for one eye and not for the other, or an optimum at one time and at
    one distance and not at others. Among these unaccountable optimums one
    often finds a particular letter on the Snellen test card. One patient,
    for instance, was able to see the letter K on the forty, fifteen and
    ten lines, but could see none of the other letters on these lines,
    although most patients would see some of them, on account of the
    simplicity of their outlines, better than they would such a letter as
    K.

    Pessimums may be as curious and unaccountable as optimums. The letter
    V is so simple in its outlines that many people can see it when they
    cannot see others on the same line. Yet some people are unable to
    distinguish it at any distance, although able to read other letters in
    the same word, or on the same line of the Snellen test card. Some
    people again will not only be unable to recognize the letter V in a
    word, but also to read any word that contains it, the pessimum
    lowering their sight not only for itself but for other objects. Some
    letters, or objects, become pessimums only in particular situations. A
    letter, for instance, may be a pessimum when located at the end, or at
    the beginning of a line, or sentence, and not in other places. When
    the attention of the patient is called to the fact that a letter seen
    in one location ought logically to be seen equally well in others, the
    letter often ceases to be a pessimum in any situation.

    A pessimum, like an optimum may be lost and later become manifest. It
    may vary according to the light and distance. An object which is a
    pessimum in a moderate light may not be so when the light is increased
    or diminished. A pessimum at twenty feet may not be one at two feet,
    or thirty feet, and an object which is a pessimum when directly
    regarded may be seen with normal vision in the eccentric field - that
    is, when not directly regarded.

    For most people the Snellen test card is a pessimum. If you can see
    the Snellen test card with normal vision, you can see almost anything
    else in the world. Patients who cannot see the letters on the Snellen
    test card can often see other objects of the same size and at the same
    distance with normal sight. When letters which are seen imperfectly,
    or even letters which cannot be seen at all, or which the patient is
    not conscious of seeing, are regarded, the error of refraction is
    increased. The patient may regard a blank white card without any error
    of refraction; but if he regards the lower part of a Snellen test
    card, which appears to him to be just as blank as the blank test card,
    an error of refraction can always be demonstrated, and if the visible
    letters of the card are covered the result is the same. The pessimum
    may, in short, be letters or objects which the patient is not
    conscious of seeing. This phenomenon is very common. When the card is
    seen in the eccentric field it may have the effect of lowering the
    vision for the point directly regarded. For instance, a patient may
    regard an area of green wall-paper at the distance, and see the color
    as well as at the near-point; but if a Snellen test card on which the
    letters are either seen imperfectly, or not seen at all, is placed in
    the neighborhood of the area being regarded, the retinoscope may
    indicate an error of refraction. When the vision improves, the numbers
    of letters on the card which are pessimums diminishes, and the number
    of optimums increases, until the whole card becomes an optimum.

    A pessimum, like an optimum, is a manifestation of the mind. It is
    something associated with a strain to see, just as an optimum is
    something which has no such association. It is not caused by the error
    of refraction, but always produces an error of refraction; and when
    the strain has been relieved it ceases to be a pessimum and becomes an
    optimum.

    [...]
     
    Zetsu, Jun 13, 2009
    #1
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  2. Zetsu

    Neil Brooks Guest

    Zetsu has long ago reached the level where he/she/it is nothing
    more than the online equivalent of one of those psychotic homeless
    people who stands on the corner, SHOUTING Bible passages, to ...
    nobody.

    What a pathetic little creature.

    Almost SURELY the illegitimate love child of Otis Brown (and ... who
    else?? Desperate people DO do desperate things....).
     
    Neil Brooks, Jun 13, 2009
    #2
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