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Modification of the Indirect Ophthalmoscopic Condensing Lens
736
AMERICAN JOURNAL OF OPHTHALMOLOGY
MODIFICATION OF THE INDIRECT OPHTHALMOSCOPIC CONDENSING LENS A L L E N Z. V E R N E , M.D.,
AND
G I L B E R T W. C L E A S B Y ,
M.D.
NOVEMBER, 1977
5 mm
San Francisco, California
Since the improvement and populariza tion of Schepens'1 indirect ophthalmo scope, it has proved an indispensable tool in performing a complete ophthalmological examination. Various viewing lenses may be used, including the 14-diopter lens, the 20-diopter lens, and the 30diopter lens. These lenses may be diffi cult to position properly for an optimum view of the fundus. We modified a con densing lens to facilitate lens positioning and manipulation during the course of the indirect ophthalmoscopic examina tion. MATERIAL AND METHODS
The desired lens is ordered from an optical company with the following in structions : the lens is to be removed from its ring, and a 5-mm "nasal cut" is to be made on the lens (Fig. 1).
Fig. 1 (Verne and Cleasby). Diagram illustrating the 5-mm nasal cut.
The stronger condensing lenses, which are held closer to the eye, are frequently difficult to position. This is especially
DISCUSSION
High power condensing lenses give less magnification, less depth percep tion,2 and are often difficult to position. But these lenses are frequently valuable because they provide a larger field of view. A larger viewing area is important in examining a lesion too large to see completely with a lower powered con densing lense. Viewing a larger area of the patient's fundus makes it easier to evaluate pathological and anatomical re lationships. From the Department of Ophthalmology, Presby terian Hospital of Pacific Medical Center, San Fran cisco, California. Reprint requests to Gilbert W. Cleasby, M.D., 2400 Clay St., San Francisco, CA 94115.
Fig. 2 (Verne and Cleasby). Indirect condensing lens after removal of the ring, showing the 5-mm nasal cut.
VOL. 84, NO. 5
NOTES, CASES, INSTRUMENTS
true in patients with large noses or re cessed eyes, or both. Removal of the lens-retaining ring enhances one's ability to position the lens properly, but this alone may not be sufficient. A 5-mm nasal cut, in addition to removing the retaining ring (Fig. 2), allows for more effective lense positioning. The nasal cut also makes lens manipulation easier because the flat surface facilitates grasping. Addi tionally, removal of the lens-retaining ring permits more effective cleaning and sterilization in the operating room.
737
SUMMARY
Removal of the lens retaining ring in conjunction with a 5-mm "nasal cut" is an easy, inexpensive way to facilitate opti mum positioning and thus improve the efficacy of the indirect ophthalmoscopic examination. REFERENCES 1. Schepens, C. L.: A new ophthalmoscope dem onstration. Trans. Am. Acad. Ophthalmol. Otolaryngol. 51:298, 1947. 2. Rubin, M. L.: The optics of indirect ophthalmoscopy. Survey Ophthalmol. 9:449, 1964.
AMERICAN JOURNAL OF OPHTHALMOLOGY
MODIFICATION OF THE INDIRECT OPHTHALMOSCOPIC CONDENSING LENS A L L E N Z. V E R N E , M.D.,
AND
G I L B E R T W. C L E A S B Y ,
M.D.
NOVEMBER, 1977
5 mm
San Francisco, California
Since the improvement and populariza tion of Schepens'1 indirect ophthalmo scope, it has proved an indispensable tool in performing a complete ophthalmological examination. Various viewing lenses may be used, including the 14-diopter lens, the 20-diopter lens, and the 30diopter lens. These lenses may be diffi cult to position properly for an optimum view of the fundus. We modified a con densing lens to facilitate lens positioning and manipulation during the course of the indirect ophthalmoscopic examina tion. MATERIAL AND METHODS
The desired lens is ordered from an optical company with the following in structions : the lens is to be removed from its ring, and a 5-mm "nasal cut" is to be made on the lens (Fig. 1).
Fig. 1 (Verne and Cleasby). Diagram illustrating the 5-mm nasal cut.
The stronger condensing lenses, which are held closer to the eye, are frequently difficult to position. This is especially
DISCUSSION
High power condensing lenses give less magnification, less depth percep tion,2 and are often difficult to position. But these lenses are frequently valuable because they provide a larger field of view. A larger viewing area is important in examining a lesion too large to see completely with a lower powered con densing lense. Viewing a larger area of the patient's fundus makes it easier to evaluate pathological and anatomical re lationships. From the Department of Ophthalmology, Presby terian Hospital of Pacific Medical Center, San Fran cisco, California. Reprint requests to Gilbert W. Cleasby, M.D., 2400 Clay St., San Francisco, CA 94115.
Fig. 2 (Verne and Cleasby). Indirect condensing lens after removal of the ring, showing the 5-mm nasal cut.
VOL. 84, NO. 5
NOTES, CASES, INSTRUMENTS
true in patients with large noses or re cessed eyes, or both. Removal of the lens-retaining ring enhances one's ability to position the lens properly, but this alone may not be sufficient. A 5-mm nasal cut, in addition to removing the retaining ring (Fig. 2), allows for more effective lense positioning. The nasal cut also makes lens manipulation easier because the flat surface facilitates grasping. Addi tionally, removal of the lens-retaining ring permits more effective cleaning and sterilization in the operating room.
737
SUMMARY
Removal of the lens retaining ring in conjunction with a 5-mm "nasal cut" is an easy, inexpensive way to facilitate opti mum positioning and thus improve the efficacy of the indirect ophthalmoscopic examination. REFERENCES 1. Schepens, C. L.: A new ophthalmoscope dem onstration. Trans. Am. Acad. Ophthalmol. Otolaryngol. 51:298, 1947. 2. Rubin, M. L.: The optics of indirect ophthalmoscopy. Survey Ophthalmol. 9:449, 1964.