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Diagnostic Illumination Test for Keratoconus
141
NOTES, CASES, INSTRUMENTS
VOL. 70, NO. 1
DIAGNOSTIC I L L U M I N A T I O N T E S T FOR KERATOCONUS A. BENEDICT RIZZUTI,
M.D.
Brooklyn, New York
Fig. 1 (Weinstein). Overall and close-up view of the orbital rake and shovel retractors, illustrat ing the semi-sharp teeth on the rake retractor with its slight concave curvature, and the convex curva ture of the shovel retractor.
orbital contents are retrieved from the bony defect, as confirmed by traction on a bridle suture previously placed beneath the inser tion of the inferior rectus muscle. The globe and its attached soft tissues are then gently retracted with the "shovel," permitting full visualization of the bony defect. The sur geon can then repair the defect by the method of his choice.
Keratoconus may be diagnosed by a vari ety of clinical signs. The following test is re ported because of its simplicity and because no special instrumentation is required. To conduct the test, the examiner holds a pensize flash light containing a 2.2-volt condens ing bulb a short distance from the temporal side of the patient's head. The beam of light is moved forward and backward anterior to the plane of the iris (Fig. 1 ). In the normal cornea (Fig. 2 ) , the light From the Corneal Service of the Brooklyn Eye and Ear Hospital and Department of Ophthalmol ogy of New York Medical College. This study was supported in part by USPHS Research Grant NB-07162; United Health Foundation, Inc., Grant 68-138 and a Grant from the Cancer Service League, Inc. Reprint requests to A. Benedict Rizzuti, M.D. 160 Henry St., Brooklyn, New York 11201.
SUMMARY
To expose orbital tissues in blow-out fractures, a miniature rake was designed to retract the lower edge of the skin muscle incision. A miniature shovel was designed to retract the globe and soft tissue to permit visualization of the bony defects. REFERENCE
1. Bedrossian, R. H. Orbital Retractor. Am. J. Ophth. 57:484, 1964.
Fig. 1 (Rizzuti). The nasal aspect of the cornea is illuminated by holding an ordinary penlight on the temporal side of the patient and parallel to the iris plane.
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AMERICAN JOURNAL OF OPHTHALMOLOGY
JULY, 1970
Fig. 2 (Rizzuti). Lateral illumination from the temporal side illuminates the nasal limbal area evenly in normal eye.
rays that emerge illuminate the nasal corneoscleral limbus diffusely and evenly. In keratoconus, the light rays focus sharply in the region of the nasal limbus. In small de grees of keratoconus, the converging rays of the light focus inside the limbus (Fig. 3) ; the focus in moderate and severe cases, is il lustrated in Figures 4 and 5. In advanced keratoconus, the light rays focus outside the nasal limbus. When the
apex of the cornea loses its cone-like appear ance, as occurs in extreme keratoconus or keratoglobus, the light rays then fail to con verge to a sharp focus and the corneal limbal zone is diffusely illuminated. In routine eye examination this test is useful and easy to perform. However, it should be noted that the test can be elicited in patients with severe refractive errors, particularly myopic corneal astigmatism. If
Fig. 3 (Rizzuti). In mild keratoconus, the light rays converge sharply inside the nasal limbus.
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NOTES, CASES, INSTRUMENTS
143
Fig. 4 (Rizzuti). In moderate keratoconus, the light rays focus at the nasal limbus. the light source is moved posterior to the plane of the iris, a false positive result is ob tained. SUMMARY
Keratoconus may be detected by directing the beam of a pen-sized flashlight into the temporal corneoscleral limbus and moving it forward and backward anterior to the plane of the iris. In a normal cornea, the rays
emerge to illuminate the nasal corneoscleral limbus diffusly and evenly. In keratoconus, the light rays focus sharply in the region of the nasal limbus. In smaller degrees of kera toconus, the converging rays of the light focus inside the limbus, and in severe cases they focus outside the limbus. The sign dis appears in keratoglobus. It may, however, be elicited in patients with severe refractive er rors particularly myopic corneal astigmatism.
Fig. 5 (Rizzuti). In advanced keratoconus, the temporal light rays focus beyond the nasal limbus.
NOTES, CASES, INSTRUMENTS
VOL. 70, NO. 1
DIAGNOSTIC I L L U M I N A T I O N T E S T FOR KERATOCONUS A. BENEDICT RIZZUTI,
M.D.
Brooklyn, New York
Fig. 1 (Weinstein). Overall and close-up view of the orbital rake and shovel retractors, illustrat ing the semi-sharp teeth on the rake retractor with its slight concave curvature, and the convex curva ture of the shovel retractor.
orbital contents are retrieved from the bony defect, as confirmed by traction on a bridle suture previously placed beneath the inser tion of the inferior rectus muscle. The globe and its attached soft tissues are then gently retracted with the "shovel," permitting full visualization of the bony defect. The sur geon can then repair the defect by the method of his choice.
Keratoconus may be diagnosed by a vari ety of clinical signs. The following test is re ported because of its simplicity and because no special instrumentation is required. To conduct the test, the examiner holds a pensize flash light containing a 2.2-volt condens ing bulb a short distance from the temporal side of the patient's head. The beam of light is moved forward and backward anterior to the plane of the iris (Fig. 1 ). In the normal cornea (Fig. 2 ) , the light From the Corneal Service of the Brooklyn Eye and Ear Hospital and Department of Ophthalmol ogy of New York Medical College. This study was supported in part by USPHS Research Grant NB-07162; United Health Foundation, Inc., Grant 68-138 and a Grant from the Cancer Service League, Inc. Reprint requests to A. Benedict Rizzuti, M.D. 160 Henry St., Brooklyn, New York 11201.
SUMMARY
To expose orbital tissues in blow-out fractures, a miniature rake was designed to retract the lower edge of the skin muscle incision. A miniature shovel was designed to retract the globe and soft tissue to permit visualization of the bony defects. REFERENCE
1. Bedrossian, R. H. Orbital Retractor. Am. J. Ophth. 57:484, 1964.
Fig. 1 (Rizzuti). The nasal aspect of the cornea is illuminated by holding an ordinary penlight on the temporal side of the patient and parallel to the iris plane.
142
AMERICAN JOURNAL OF OPHTHALMOLOGY
JULY, 1970
Fig. 2 (Rizzuti). Lateral illumination from the temporal side illuminates the nasal limbal area evenly in normal eye.
rays that emerge illuminate the nasal corneoscleral limbus diffusely and evenly. In keratoconus, the light rays focus sharply in the region of the nasal limbus. In small de grees of keratoconus, the converging rays of the light focus inside the limbus (Fig. 3) ; the focus in moderate and severe cases, is il lustrated in Figures 4 and 5. In advanced keratoconus, the light rays focus outside the nasal limbus. When the
apex of the cornea loses its cone-like appear ance, as occurs in extreme keratoconus or keratoglobus, the light rays then fail to con verge to a sharp focus and the corneal limbal zone is diffusely illuminated. In routine eye examination this test is useful and easy to perform. However, it should be noted that the test can be elicited in patients with severe refractive errors, particularly myopic corneal astigmatism. If
Fig. 3 (Rizzuti). In mild keratoconus, the light rays converge sharply inside the nasal limbus.
VOL. 70, NO. 1
NOTES, CASES, INSTRUMENTS
143
Fig. 4 (Rizzuti). In moderate keratoconus, the light rays focus at the nasal limbus. the light source is moved posterior to the plane of the iris, a false positive result is ob tained. SUMMARY
Keratoconus may be detected by directing the beam of a pen-sized flashlight into the temporal corneoscleral limbus and moving it forward and backward anterior to the plane of the iris. In a normal cornea, the rays
emerge to illuminate the nasal corneoscleral limbus diffusly and evenly. In keratoconus, the light rays focus sharply in the region of the nasal limbus. In smaller degrees of kera toconus, the converging rays of the light focus inside the limbus, and in severe cases they focus outside the limbus. The sign dis appears in keratoglobus. It may, however, be elicited in patients with severe refractive er rors particularly myopic corneal astigmatism.
Fig. 5 (Rizzuti). In advanced keratoconus, the temporal light rays focus beyond the nasal limbus.