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The Scotometer*
NOTES, CASES, INSTRUMENTS T H E SCOTOMETER* A DEVICE FOR MEASURING MACULAR RECOVERY TIME PAUL H E N K I N D ,
M.D.
AND IRWIN M.
SIEGEL, P H . D .
New York
A number of recent reports1"4 indicate that the recovery time of visual sensitivity and acuity following intense illumination of the macula may be significantly lengthened in a variety of disorders. While gross test ing of this function can be performed sim ply by illuminating the macula with an oph thalmoscope and then having the patient read a visual acuity chart at 20 feet, a more sophisticated method has also been used.6 Though the mechanisms responsible for increased recovery time are not known, the phenomenon itself appears related to the persistence of an intense positive after image (negative scotoma) induced by the bright light. A new, hand-held, self-contained instru ment has been developed which answers the need for a simple but reliable technique with which to measure macular recovery time fol lowing intense illumination (fig. 1). The hand-grip of the device (containing the bat teries) is held by the patient who places the viewing tube close to his eye. As the patient looks into the instrument, the chart illumination is switched on by the examiner, and the reduced Snellen chart is viewed by the patient's eye at optical infinity. He is then asked to read the small est line that he can (using a distance correc tion when appropriate) ; the dazzling light is then turned on and the patient is directed to look into its center for 10 seconds. It is then From the Department of Ophthalmology, New York University College of Medicine. * Available from Medin, Inc. 29 Main Avenue, Wallington, New Jersey 07057.
extinguished by returning the lever to the original position; thereby illuminating the test chart. The patient endeavors to see the chart through the bright after-image. He is asked to continue looking at the lines of let ters (or numbers) until he finally visualizes the one which he read prior to being daz zled. The time in seconds that it takes for him to return to the original acuity is noted. A small lever at the back of the instrument (fig. 1) allows the examiner to replace the chart with one having different test figures. Chart substitution is a useful control when repetitively testing the same patient. Prelim inary studies indicate that there is little difference if the test is performed with a di lated pupil, or if the room illumination is altered. Results on normal individuals, 40 years of age or younger, reveal a maximum recov ery time of about 40 seconds. There is a definite increase in recovery time with aging, a finding already noted by Severin and co-workers.5 Markedly increased recov ery times have been measured in patients with systemic lupus erythematosus who are taking chloroquine6 and in several patients with central serous retinopathy. Of particu lar interest is the fact that recovery times as long as 180 seconds are found in chloroquine-treated lupus patients many of whom have normal visual acuity and normal fundi. The viewing conditions of the Snellen chart, under which the patient determines his recovery end-point, and the luminance of the dazzle light are two parameters of the procedure which must be invariant if reli able results are to be obtained. To these ends the optics of the instrument guarantee infinity viewing of the chart, and mercurycell batteries, or the use of a transformer (which may be purchased separately) en sure that the dazzle light and chart illumina tor are kept at rated output. It is felt that the Scotometer will provide a relatively
315
NOTES, CASES, INSTRUMENTS
VOL. 64, NO. 2
CHART
Fig. 1 (Henkind and Siegel). The Scotoraeter. The patient places the eyepiece close to his eye and views an illuminated Snellen chart at optical infinity. An intense after image is produced by a bright light which is moved into position by flipping the dazzle lever. Substitu tion of a different test chart for repetitive testing is accomplished by a forward movement of the chart lever. Power for the dazzle lamp and chart illumination is pro vided by two D-sized batteries lo cated in the hand grip.
LEVER
EYE PIECE
HAND
inexpensive means to measure recovery time quickly and reliably in patients with a vari ety of central lesions. 550 First Avenue (10016) REFERENCES
1. Magder, H. : Test for central serous retinop athy. Am. J. Ophth. 49:147, 1960. 2. Chilaris, G. A. : Recovery time after macular illumination. Am. J. Ophth. S3 :311, 1962. 3. Paul, S. D. and Batra, D. V.: Macular illu mination tests. Am. J. Ophth. 61:99, 1966. 4. Batra, D. V. and Paul, S. D. : Macular illu mination tests in central serous retinopathy. Am. J. Ophth. 63:146, 1967. 5. Severin, S. L., Tour, R. L. and Kershaw, R. H. : Macular function and the photostress test 1. Arch. Ophth. 77:2, 1967. 6. Henkind, P., Carr, R. E. and Rothfield, N. : Chloroquine retinopathy: Long-term follow-up. Presented at the interim meeting of the Am. Rheumatism A., Cincinnati, December, 1966.
S I M P L I F I E D T E C H N I Q U E FOR LOCALIZATION AND D I A T H E R M Y OF RETINAL LESIONS WILLIAM V. DELANEY, JR.,
DAZZLE LEVER
M.D.
Syracuse, New York
Localization of retinal tears at surgery requires some form of scierai indentation or From the Department of Ophthalmology, State University of New York Upstate Medical Cen ter.
GRIP
transillumination. Standard techniques re quire the observer to direct his assistant in indentation with the diathermy tip until the proper location is found. This method ne cessitates skilled assistance. Recently, a transilluminating tip has been described which would seem to be an improvement ex cept for its complex design.1 Havener and Cahn (fig. 1) have de scribed the use of forceps to grasp the sciera over the retinal tear for indentation.2 This technique is easily learned and with practice one can usually apply the forceps directly over the tear with one grasp nearly 80% of the time. The main objection to this method is that the operator cannot observe the diathermy being applied and must judge its intensity by the external effect on the sciera or be satisfied his localization is cor rect if no internal mark is achieved. Recalling general surgical days when Bovie current was applied directly to hemostats on blood vessels, a similar approach was tried on eyes. INSTRUMENT AND TECHNIQUE
A corneoscleral forceps with 0.5-mm teeth was insulated with lacquer* along both shafts, leaving exposed only the teeth and * Storz Instrument Company, St. Louis, Missouri.
M.D.
AND IRWIN M.
SIEGEL, P H . D .
New York
A number of recent reports1"4 indicate that the recovery time of visual sensitivity and acuity following intense illumination of the macula may be significantly lengthened in a variety of disorders. While gross test ing of this function can be performed sim ply by illuminating the macula with an oph thalmoscope and then having the patient read a visual acuity chart at 20 feet, a more sophisticated method has also been used.6 Though the mechanisms responsible for increased recovery time are not known, the phenomenon itself appears related to the persistence of an intense positive after image (negative scotoma) induced by the bright light. A new, hand-held, self-contained instru ment has been developed which answers the need for a simple but reliable technique with which to measure macular recovery time fol lowing intense illumination (fig. 1). The hand-grip of the device (containing the bat teries) is held by the patient who places the viewing tube close to his eye. As the patient looks into the instrument, the chart illumination is switched on by the examiner, and the reduced Snellen chart is viewed by the patient's eye at optical infinity. He is then asked to read the small est line that he can (using a distance correc tion when appropriate) ; the dazzling light is then turned on and the patient is directed to look into its center for 10 seconds. It is then From the Department of Ophthalmology, New York University College of Medicine. * Available from Medin, Inc. 29 Main Avenue, Wallington, New Jersey 07057.
extinguished by returning the lever to the original position; thereby illuminating the test chart. The patient endeavors to see the chart through the bright after-image. He is asked to continue looking at the lines of let ters (or numbers) until he finally visualizes the one which he read prior to being daz zled. The time in seconds that it takes for him to return to the original acuity is noted. A small lever at the back of the instrument (fig. 1) allows the examiner to replace the chart with one having different test figures. Chart substitution is a useful control when repetitively testing the same patient. Prelim inary studies indicate that there is little difference if the test is performed with a di lated pupil, or if the room illumination is altered. Results on normal individuals, 40 years of age or younger, reveal a maximum recov ery time of about 40 seconds. There is a definite increase in recovery time with aging, a finding already noted by Severin and co-workers.5 Markedly increased recov ery times have been measured in patients with systemic lupus erythematosus who are taking chloroquine6 and in several patients with central serous retinopathy. Of particu lar interest is the fact that recovery times as long as 180 seconds are found in chloroquine-treated lupus patients many of whom have normal visual acuity and normal fundi. The viewing conditions of the Snellen chart, under which the patient determines his recovery end-point, and the luminance of the dazzle light are two parameters of the procedure which must be invariant if reli able results are to be obtained. To these ends the optics of the instrument guarantee infinity viewing of the chart, and mercurycell batteries, or the use of a transformer (which may be purchased separately) en sure that the dazzle light and chart illumina tor are kept at rated output. It is felt that the Scotometer will provide a relatively
315
NOTES, CASES, INSTRUMENTS
VOL. 64, NO. 2
CHART
Fig. 1 (Henkind and Siegel). The Scotoraeter. The patient places the eyepiece close to his eye and views an illuminated Snellen chart at optical infinity. An intense after image is produced by a bright light which is moved into position by flipping the dazzle lever. Substitu tion of a different test chart for repetitive testing is accomplished by a forward movement of the chart lever. Power for the dazzle lamp and chart illumination is pro vided by two D-sized batteries lo cated in the hand grip.
LEVER
EYE PIECE
HAND
inexpensive means to measure recovery time quickly and reliably in patients with a vari ety of central lesions. 550 First Avenue (10016) REFERENCES
1. Magder, H. : Test for central serous retinop athy. Am. J. Ophth. 49:147, 1960. 2. Chilaris, G. A. : Recovery time after macular illumination. Am. J. Ophth. S3 :311, 1962. 3. Paul, S. D. and Batra, D. V.: Macular illu mination tests. Am. J. Ophth. 61:99, 1966. 4. Batra, D. V. and Paul, S. D. : Macular illu mination tests in central serous retinopathy. Am. J. Ophth. 63:146, 1967. 5. Severin, S. L., Tour, R. L. and Kershaw, R. H. : Macular function and the photostress test 1. Arch. Ophth. 77:2, 1967. 6. Henkind, P., Carr, R. E. and Rothfield, N. : Chloroquine retinopathy: Long-term follow-up. Presented at the interim meeting of the Am. Rheumatism A., Cincinnati, December, 1966.
S I M P L I F I E D T E C H N I Q U E FOR LOCALIZATION AND D I A T H E R M Y OF RETINAL LESIONS WILLIAM V. DELANEY, JR.,
DAZZLE LEVER
M.D.
Syracuse, New York
Localization of retinal tears at surgery requires some form of scierai indentation or From the Department of Ophthalmology, State University of New York Upstate Medical Cen ter.
GRIP
transillumination. Standard techniques re quire the observer to direct his assistant in indentation with the diathermy tip until the proper location is found. This method ne cessitates skilled assistance. Recently, a transilluminating tip has been described which would seem to be an improvement ex cept for its complex design.1 Havener and Cahn (fig. 1) have de scribed the use of forceps to grasp the sciera over the retinal tear for indentation.2 This technique is easily learned and with practice one can usually apply the forceps directly over the tear with one grasp nearly 80% of the time. The main objection to this method is that the operator cannot observe the diathermy being applied and must judge its intensity by the external effect on the sciera or be satisfied his localization is cor rect if no internal mark is achieved. Recalling general surgical days when Bovie current was applied directly to hemostats on blood vessels, a similar approach was tried on eyes. INSTRUMENT AND TECHNIQUE
A corneoscleral forceps with 0.5-mm teeth was insulated with lacquer* along both shafts, leaving exposed only the teeth and * Storz Instrument Company, St. Louis, Missouri.