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A Modified Holth Punch*
1542
NOTES, CASES, INSTRUMENTS 7. Gonioscopy is simple, easy and well tolerated. 8. The lens is completely self-retaining, leaving one or both hands of the examiner free. It does not become extruded when the patient squeezes his lids together. New York Medical College Fifth Avenue at 106th Street (10029)
Fig. 1 (Friedman). A self-illuminated goniolens.
the bulb is 2.7v ; the voltage may be stepped up to 3.2v by means of the handle contacts. The higher voltage is preferable. The concavity of the lens is ground to a radius of 8.0 mm and requires a minimum amount of methyl cellulose. The light ob tained is bright and uniform, and is well di rected into the anterior chamber angle. Magnification is obtained by the lens itself plus an examining loupe, or by a hand-held binocular microscope. The total magnifica tion can range from X 4 to X12 for com fortable observation. An adult size and a child size goniolens are available. A brass extension from the bulb base provides a handle and also serves the pur pose of diverting heat from the lens to the exterior. The lens is not intended to supplant the slitlamp for gonioscopy but it has certain advantages : 1. It permits rapid and adequate exami nation of the chamber angle over a 360 de gree circuit. 2. It is small, compact and simple. 3. It eliminates the immediate need for the slitlamp, a feature common to all Koeppe-type lenses. When greater details are required, the lens permits scouting local ization of pathologic alterations prior to slit lamp study. 4. It may be used in the office, clinic, or operating room or at the bedside. It does not require house current. 5. It is useful when general anesthesia is mandatory. 6. The patient is recumbent and need not be positioned before the slitlamp.
ACKNOWLEDGMENT
The lens was constructed by Mr. Tom Cogger of Obrig Laboratories, Inc., 75 East 55th Street, New York.
A MODIFIED H O L T H PUNCH* M.
HARVEY R U B I N ,
M.D.
Greensboro, North Carolina Posterior lip sclerectomy has become in creasing popular over the past several years as a filtering operation in the treatment of glaucoma. The most commonly used instru ment for a posterior lip sclerectomy is the Holth punch (fig. 1-A). Usually, a scratch incision is made through the full thickness of the sciera and a 1.5- or 2.0-mm Holth punch is used to make several bites at the posterior lip. Two common difficulties are an incomplete bite of the sciera, leaving a thin layer of sciera with subsequent inade quate filtration, or punching out a portion of the deeper structures. In order to simplify the surgical pro cedure and to prevent complications, a modification of the Holth punch has been devised (fig. 1-Â+). The lower blade of the punch is considerably thinner, which makes for easier insertion beneath the sciera and less difficulty in producing a clean scierai bite. There is less tendency to include struc tures other than the sciera. The angle of the punch, which was originally designed for an anterior sclerectomy or keratectomy, is de* From the Division of Ophthalmology, Uni versity of North Carolina School of Medicine, Chapel Hill. + Manufactured by V. Mueller and Company, Chi cago.
NOTES. CASES, INSTRUMENTS
I\Z
1543
—·»
.1100/uv
LIGHT ADAPTED WHITE STIMULUS AT 16 Fig. 1 (Franklin and Markman). Electroretinographic potential obtained with the use of the ring electrode on the albino rabbit eye.
Fig. 1 (Rubin). (A) Original Holth punch. (B) Modified Holth punch. Note steeper angle and thinner blade. creased from 135 to 90 degrees so that it is considerably easier to place the blades in the proper section. SUMMARY
The modification of the Holth punch herein presented is intended to make the scierai excision possible with the maximum ease in surgical technique and minimize such complications as inclusion of deeper structures and incomplete section of the sciera. 1311 North Elm Street. REFERENCE
Uiff, C. E., and Haas, J. S.: Posterior lip sclerectomy. Am. J. Ophth. 54:688, 1962.
CORNEAL RING ELECTRODE* FOR RABBIT ELECTRORETINOGRAPHY J O H N B. FRANKLIN,*
M.D.
AND DAVID A. MARKMAN,
M.D.
Houston, Texas Scierai contact lens electrodes, developed independently by Riggs, 1 in 1941, and Karpe, 2 in 1945, permitted recording of the * From the Department of Ophthalmology, Bay lor University College of Medicine. t Postdoctoral Fellow, National Institute of Neu rological Diseases and Blindness.
human electroretinogram under clinical con ditions. Adaptation of human contact lens electrodes for rabbit electroretinography is difficult, and often impractical. The large size of the human contact lens electrode rel ative to the conjunctival fornices of a rabbit will not permit a fit of the human lens with out trauma to the palpebra. Gills and Hobson 3 have modified a Burian-Allen contact lens electrode for rabbit electroretinography. The modification was accomplished by a decrease in the width of the scierai flange of the human electrode. This electrode, however, is difficult to insert, and due to variation in size of the palpebral fissure in rabbits, often can not be inserted without trauma to the animal. These investi gators are currently employing a Reudemann contact lens electrode which has been thinned to smaller size. Jacobson4 has advised the use of a needle electrode for rabbit studies. This electrode consists of a hypodermic needle to which a lead wire is soldered. The needle is embed ded in the limbal conjunctiva under topical anesthesia. Although the needles are difficult to place properly, this technique yields very satisfactory records. Continued use of the needle electrode, as in a long-term study, creates a significant degree of fibrosis and conjunctival damage. This paper describes a gold-plated brassring electrode which can be easily and inex pensively machined from metal stock found in most machine shops. The electrode is a modification of a 24-carat gold-ring elec trode described by Ziv,5 in 1961. The elec trode is specifically designed to fit the rabbit
NOTES, CASES, INSTRUMENTS 7. Gonioscopy is simple, easy and well tolerated. 8. The lens is completely self-retaining, leaving one or both hands of the examiner free. It does not become extruded when the patient squeezes his lids together. New York Medical College Fifth Avenue at 106th Street (10029)
Fig. 1 (Friedman). A self-illuminated goniolens.
the bulb is 2.7v ; the voltage may be stepped up to 3.2v by means of the handle contacts. The higher voltage is preferable. The concavity of the lens is ground to a radius of 8.0 mm and requires a minimum amount of methyl cellulose. The light ob tained is bright and uniform, and is well di rected into the anterior chamber angle. Magnification is obtained by the lens itself plus an examining loupe, or by a hand-held binocular microscope. The total magnifica tion can range from X 4 to X12 for com fortable observation. An adult size and a child size goniolens are available. A brass extension from the bulb base provides a handle and also serves the pur pose of diverting heat from the lens to the exterior. The lens is not intended to supplant the slitlamp for gonioscopy but it has certain advantages : 1. It permits rapid and adequate exami nation of the chamber angle over a 360 de gree circuit. 2. It is small, compact and simple. 3. It eliminates the immediate need for the slitlamp, a feature common to all Koeppe-type lenses. When greater details are required, the lens permits scouting local ization of pathologic alterations prior to slit lamp study. 4. It may be used in the office, clinic, or operating room or at the bedside. It does not require house current. 5. It is useful when general anesthesia is mandatory. 6. The patient is recumbent and need not be positioned before the slitlamp.
ACKNOWLEDGMENT
The lens was constructed by Mr. Tom Cogger of Obrig Laboratories, Inc., 75 East 55th Street, New York.
A MODIFIED H O L T H PUNCH* M.
HARVEY R U B I N ,
M.D.
Greensboro, North Carolina Posterior lip sclerectomy has become in creasing popular over the past several years as a filtering operation in the treatment of glaucoma. The most commonly used instru ment for a posterior lip sclerectomy is the Holth punch (fig. 1-A). Usually, a scratch incision is made through the full thickness of the sciera and a 1.5- or 2.0-mm Holth punch is used to make several bites at the posterior lip. Two common difficulties are an incomplete bite of the sciera, leaving a thin layer of sciera with subsequent inade quate filtration, or punching out a portion of the deeper structures. In order to simplify the surgical pro cedure and to prevent complications, a modification of the Holth punch has been devised (fig. 1-Â+). The lower blade of the punch is considerably thinner, which makes for easier insertion beneath the sciera and less difficulty in producing a clean scierai bite. There is less tendency to include struc tures other than the sciera. The angle of the punch, which was originally designed for an anterior sclerectomy or keratectomy, is de* From the Division of Ophthalmology, Uni versity of North Carolina School of Medicine, Chapel Hill. + Manufactured by V. Mueller and Company, Chi cago.
NOTES. CASES, INSTRUMENTS
I\Z
1543
—·»
.1100/uv
LIGHT ADAPTED WHITE STIMULUS AT 16 Fig. 1 (Franklin and Markman). Electroretinographic potential obtained with the use of the ring electrode on the albino rabbit eye.
Fig. 1 (Rubin). (A) Original Holth punch. (B) Modified Holth punch. Note steeper angle and thinner blade. creased from 135 to 90 degrees so that it is considerably easier to place the blades in the proper section. SUMMARY
The modification of the Holth punch herein presented is intended to make the scierai excision possible with the maximum ease in surgical technique and minimize such complications as inclusion of deeper structures and incomplete section of the sciera. 1311 North Elm Street. REFERENCE
Uiff, C. E., and Haas, J. S.: Posterior lip sclerectomy. Am. J. Ophth. 54:688, 1962.
CORNEAL RING ELECTRODE* FOR RABBIT ELECTRORETINOGRAPHY J O H N B. FRANKLIN,*
M.D.
AND DAVID A. MARKMAN,
M.D.
Houston, Texas Scierai contact lens electrodes, developed independently by Riggs, 1 in 1941, and Karpe, 2 in 1945, permitted recording of the * From the Department of Ophthalmology, Bay lor University College of Medicine. t Postdoctoral Fellow, National Institute of Neu rological Diseases and Blindness.
human electroretinogram under clinical con ditions. Adaptation of human contact lens electrodes for rabbit electroretinography is difficult, and often impractical. The large size of the human contact lens electrode rel ative to the conjunctival fornices of a rabbit will not permit a fit of the human lens with out trauma to the palpebra. Gills and Hobson 3 have modified a Burian-Allen contact lens electrode for rabbit electroretinography. The modification was accomplished by a decrease in the width of the scierai flange of the human electrode. This electrode, however, is difficult to insert, and due to variation in size of the palpebral fissure in rabbits, often can not be inserted without trauma to the animal. These investi gators are currently employing a Reudemann contact lens electrode which has been thinned to smaller size. Jacobson4 has advised the use of a needle electrode for rabbit studies. This electrode consists of a hypodermic needle to which a lead wire is soldered. The needle is embed ded in the limbal conjunctiva under topical anesthesia. Although the needles are difficult to place properly, this technique yields very satisfactory records. Continued use of the needle electrode, as in a long-term study, creates a significant degree of fibrosis and conjunctival damage. This paper describes a gold-plated brassring electrode which can be easily and inex pensively machined from metal stock found in most machine shops. The electrode is a modification of a 24-carat gold-ring elec trode described by Ziv,5 in 1961. The elec trode is specifically designed to fit the rabbit