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Hand Tangent Screen*
NOTES, CASES, INSTRUMENTS
HAND TANGENT SCREEN* R O L A N D I.
PRITIKIN,
Rockford,
M.D.
Illinois
It is not sufficient in many instances to know only about the central visual acuity of the individual who is being tested. The Snellen chart will give the patient's distance vision and the Jaeger chart will give his reading vision. If some dysfunction in the central visual field is suspected, a test should be made with a tangent screen. A portable screen for such a test is not always available in the field, aboard ship, or with a flight unit. It is sug gested that a hand tangent screen (fig. 1) be carried in the eye chests of the Army, Navy, Air Force, and similar units. The hand tangent screen illustrated in Fig ure 1 may also be taken to the patient's bed side, to the home, or hospital, where it would be impractical to transport a large tangent screen. It may be used in any and all condi tions—to chart central visual fields, as an aid in diagnosis, and as a diagnostic screening device in the large and busy clinics. It is so compact and light that it can be moved or shipped as easily as a portfolio or notebook.
Fig. 1 (Pritikin). The hand tangent screen. * Manufactured by The House of Vision, 30 North Michigan Avenue, Chicago, Illinois.
565
The patient screen distance is fixed by a horizontal bar 0.25 meter, approximately 10 inches, in length. By exact application of the cheek rest to the patient's inferior or bital rim, perfect alignment and immobility of the head is assured and mechanical raising or lowering is made unnecessary. The device fits each and every patient and time-consum ing adjustments are eliminated. The screen is a flat, dark, nonreflecting metallic or plastic rectangle. The fixation target is centrally placed. It is actually the flattened head of the bolt which holds the vertical portion of the bar frame, thus there are no small parts to be lost or misplaced. Except for the targets and the wand, the whole device breaks down into five parts. Lines denoting the meridional divisions, as well as the isopters, are grooved into the screen. The physiologic blindspots, one on the right for the right eye and one on the left for the left eye, are designated. Adequate, even illumination must be sup plied, but this is no problem in the modern, well-lighted offices, clinics, and hospitals. Daylight illumination may be used if the patient's back is to the window. The test object is mounted on a wand which is manipulated by the examiner in the same manner as the wand used with a large tangent screen. Magnetic testing objects may also be used and may be moved along the face of the screen by means of a magnet, further simplifying the procedure. The cen tral field for form or color, using white, blue, red, and green, may be ascertained. Charting may be made directly on the screen with soft chalk and later transcribed to standard tangent screen charts for per manent records. Soft chalk marks may be easily wiped off with a dry or moist cloth. The wand has a small hole at each end ; the smaller hole is for the smaller targets. The targets furnished are 0.5, 1, 2, and 3 mm. in white, and 2 and 3 mm. in blue and red and green. Central vision charts are also furnished. Talcott Building.
HAND TANGENT SCREEN* R O L A N D I.
PRITIKIN,
Rockford,
M.D.
Illinois
It is not sufficient in many instances to know only about the central visual acuity of the individual who is being tested. The Snellen chart will give the patient's distance vision and the Jaeger chart will give his reading vision. If some dysfunction in the central visual field is suspected, a test should be made with a tangent screen. A portable screen for such a test is not always available in the field, aboard ship, or with a flight unit. It is sug gested that a hand tangent screen (fig. 1) be carried in the eye chests of the Army, Navy, Air Force, and similar units. The hand tangent screen illustrated in Fig ure 1 may also be taken to the patient's bed side, to the home, or hospital, where it would be impractical to transport a large tangent screen. It may be used in any and all condi tions—to chart central visual fields, as an aid in diagnosis, and as a diagnostic screening device in the large and busy clinics. It is so compact and light that it can be moved or shipped as easily as a portfolio or notebook.
Fig. 1 (Pritikin). The hand tangent screen. * Manufactured by The House of Vision, 30 North Michigan Avenue, Chicago, Illinois.
565
The patient screen distance is fixed by a horizontal bar 0.25 meter, approximately 10 inches, in length. By exact application of the cheek rest to the patient's inferior or bital rim, perfect alignment and immobility of the head is assured and mechanical raising or lowering is made unnecessary. The device fits each and every patient and time-consum ing adjustments are eliminated. The screen is a flat, dark, nonreflecting metallic or plastic rectangle. The fixation target is centrally placed. It is actually the flattened head of the bolt which holds the vertical portion of the bar frame, thus there are no small parts to be lost or misplaced. Except for the targets and the wand, the whole device breaks down into five parts. Lines denoting the meridional divisions, as well as the isopters, are grooved into the screen. The physiologic blindspots, one on the right for the right eye and one on the left for the left eye, are designated. Adequate, even illumination must be sup plied, but this is no problem in the modern, well-lighted offices, clinics, and hospitals. Daylight illumination may be used if the patient's back is to the window. The test object is mounted on a wand which is manipulated by the examiner in the same manner as the wand used with a large tangent screen. Magnetic testing objects may also be used and may be moved along the face of the screen by means of a magnet, further simplifying the procedure. The cen tral field for form or color, using white, blue, red, and green, may be ascertained. Charting may be made directly on the screen with soft chalk and later transcribed to standard tangent screen charts for per manent records. Soft chalk marks may be easily wiped off with a dry or moist cloth. The wand has a small hole at each end ; the smaller hole is for the smaller targets. The targets furnished are 0.5, 1, 2, and 3 mm. in white, and 2 and 3 mm. in blue and red and green. Central vision charts are also furnished. Talcott Building.