- Email: [email protected]
Autoclavable wide-angle contact lens for vitreous surgery
D
ISK HEMORRHAGES ARE MORE FREQUENT IN PATIENTS
with normal-tension glaucoma than other types of glaucoma and normal control subjects. Disk hemorrhage is closely associated with retinal nerve fiber layer defect in the location and size of peripapillary atrophy and is a significantly negative prognostic factor in patients with normal-tension glaucoma.1–2 Branch retinal vein occlusion does not seem to be related to intraocular pressure (IOP) and primary open-angle glaucoma, especially when occurring at an arteriovenous crossing.3 Conversely, in openangle glaucoma patients, Sonnsjo and associates4 noted that the incidence of retinal venous occlusion (10.5%) was higher than in control subjects (1.3%) and that disk hemorrhage was also present in some cases (29 of 1,026 cases). These researchers hypothesized that disk hemorrhage is the thrombosis of very small vessels. However, there has been no report dealing with branch retinal vein occlusion in normal-tension glaucoma patients with disk hemorrhage. From July 2001 to June 2002, during diagnostic workup for normal-tension glaucoma patients in the Glaucoma Clinic of Seoul National University Hospital, 15 cases of normal-tension glaucoma with disk hemorrhage in one eye were detected, four of which showed combined branch retinal vein occlusion in the contralateral eye. Twentyfour hour IOP measurement, fundus examination, retinal nerve fiber layer photography, stereo disk photography, Humphrey visual field analysis, confocal scanning laser tomography, and fluorescein angiography were performed for all four patients. Table 1 shows the clinical characteristics of the four patients. Mean age was 57 ⫾ 10 years (range, 47–71 years). Three patients (75%) had systemic hypertension. Two patients had bilateral normal-tension glaucoma and thus branch retinal vein occlusion in normal-tension glaucoma eyes. Three patients showed occlusion occurring at the arteriovenous crossing and one patient at the optic cup. Mean cup-to-disk ratio ranged from 0.5 to 0.8. There was no significant difference in IOP between the disk hemorrhage eyes and the contralateral eyes with branch retinal vein occlusion. All four patients had bilateral peripapillary atrophy and retinal nerve fiber layer defects collocated with the disk hemorrhage (Figure 1). To the best of our knowledge, this is the first report of disk hemorrhage in normal-tension glaucoma associated with contralateral branch retinal vein occlusion. These cases suggest the possibility that some disk hemorrhages in normal-tension glaucoma may have a pathogenic mechanism in common with branch retinal vein occlusion and may likewise be caused by thrombosis of very small vessels. REFERENCES
1. Sugiyama K, Tomita G, Kitazawa Y, Onda E, Shinohara H, Park KH. The associations of optic disk hemorrhage with retinal nerve fiber layer defect and peripapillary atrophy in
VOL. 137, NO. 2
normal-tension glaucoma. Ophthalmology 1997;104:1926 – 1933. 2. Ishida K, Yamamoto T, Sugiyama K, Kitazawa Y. Disk hemorrhage is a significantly negative prognostic factor in normaltension glaucoma. Am J Ophthalmol 2000;129:707–714. 3. Beaumont PE, Kang HK. Cup-to-disk ratio, intraocular pressure, and primary open-angle glaucoma in retinal venous occlusion. Ophthalmology 2002;109:282. 4. Sonnsjo B, Krakau CE. Arguments for a vascular glaucoma etiology. Acta Ophthalmol 1993;71:433–444.
Autoclavable Wide-angle Contact Lens for Vitreous Surgery Vinay A. Shah, MD, and Kakarla V. Chalam, MD To evaluate an autoclavable self-stabilizing wide-angle contact lens for vitrectomy. DESIGN: Observational study. METHOD: The wide-angle contact lens has two lens pieces within a high temperature-resistant (150 C) plastic casing. The inferior lens with footplates is made of acrylic and the superior of glass. During surgery the lens is used as the self-stabilizing wide-angle contact lens with improved stability on the eye. RESULT: The lens enables the surgeon to address the peripheral retina with less dependence on the assistant. The lens is sterilizable by autoclaving. The field of view of the wide-angle lens is 106 degrees static and 127 degrees dynamic view. CONCLUSION: The autoclavable self-stabilizing wide-angle lens reduces the cost and time for sterilization. (Am J Ophthalmol 2004;137:359 –360. © 2004 by Elsevier Inc. All rights reserved.) PURPOSE:
G
OOD VISUALIZATION OF THE FUNDUS IS CRUCIAL FOR
successful vitreous surgery. Wide-field viewing with an appropriate contact lens is a major advance in this direction. Sterilization of these lenses is traditionally done either by ethylene oxide gas or chemically by glutaraldehyde 2% or povidone iodine 5%.1 Sterilization with steam autoclaving is cost effective, fast, and widely used. However, it cannot be used for presently available wide-angle, self-stabilizing lenses.2 We describe a new autoclavable self-stabilizing, wide-angle lens for vitreous surgery. The wide-angle contact lens (Figure 1, A) has two lens pieces within a high temperature-resistant 302 F (150 C) plastic casing. The inferior part has an acrylic concavoconvex lens with footplates (Figure 1, B; refractive index [RI] 1.51). The concave contact surface has a radius of curvaAccepted for publication July 22, 2003. From the Department of Ophthalmology, University of Florida College of Medicine, Jacksonville, Florida. Inquiries to Kakarla V. Chalam, MD, Department of Ophthalmology, University of Florida College of Medicine, 580 W. 8th Street, Jacksonville, FL 32209; fax: (904) 244-9391; e-mail: [email protected]
BRIEF REPORTS
359
FIGURE 1. (A) Photograph showing the autoclavable self-stabilizing wide-angle contact lens. (B) Photograph of the superior part (X) and the inferior part (Y) of the self-stabilizing, autoclavable wide-angle lens.
After use, parts are detached, cleaned, put in a lens case, and wrapped. Standard cycle of sterilization recommended is 270 F (134 C) for 15 minutes or 250 F (121 C) for 30 minutes. Distilled water is used in the steam sterilizer to avoid deposits on the lens. The flash autoclave allows for immediate use when necessary. The lens can also be sterilized with ethylene oxide gas or with chemicals such as glutaraldehyde 2% or povidone iodine 5%.1 The wide-angle contact lens can be effectively sterilized by autoclaving. The optical surfaces are glass and acrylic, which are high temperature resistant. The casing is made of heat-resistant plastic that can withstand the heat and pressure of steam autoclaving. The lens is reassembled on cooling. The footplates provide better stability, requiring minimal assistance during difficult surgical steps or dynamic viewing. In presence of tight lids, a lateral canthotomy may be necessary. However, holding the lens is less cumbersome for the assistant than it is with a conventional lens because of the increased stability. Fogging is a disadvantage that can be avoided by proper assembly and sufficient cooling or using an intermediate liquid in between the two parts. There are reports on the handheld, irrigating steamsterilizable contact lens.3 To the best of our knowledge, there are no previous reports of an autoclavable wide-angle self-stabilizing lens for vitrectomy.
FIGURE 2. Photograph of the view of the fundus through the lens.
ture (ROC) of 7.7 mm and total cord diameter 17 mm, providing a wide contact surface for stability. The superior biconvex lens is made of glass (Figure 1, B; RI 1.883). The convex superior surface has a ROC of 6.95 mm. The inferior part slides into the superior to make the wide-angle assembly (Figure 1, A). The refractive power of the lens is 150 diopters, magnification 0.39 times, and static field of view (the total visible retina in a single field) 107 degrees; while the dynamic field (total area of the fundus that can be viewed by moving the lens on the cornea) is 127 degrees (Figure 2). The lens is kept on the cornea over a drop of viscoelastic substance. The posterior concavity, footplates, light weight (4 g), suction effect, and small size of the lens keep it stable, allowing better rotation of the globe and dynamic viewing of the retina during surgical manipulation. If required, the lens can be held or supported by an assistant with a conventional lens holder. 360
AMERICAN JOURNAL
REFERENCES
1. Das T, Sharma S, Singh J, Rao V, Chalam KV. Evaluation of glutaraldehyde and povidone iodine for sterilization of widefield contact vitrectomy lenses. Ophthalmic Surg Lasers 2001; 32:300 –304. 2. Shah VA, Chalam KV. Self-stabilizing, wide-angle contact lens for vitreous surgery. Retina. 2003;23:667– 669. 3. Parel JM, Machemer R. Steam-sterilizable fundus contact lenses. Arch Ophthalmol 1981;99:151. OF
OPHTHALMOLOGY
FEBRUARY 2004
ISK HEMORRHAGES ARE MORE FREQUENT IN PATIENTS
with normal-tension glaucoma than other types of glaucoma and normal control subjects. Disk hemorrhage is closely associated with retinal nerve fiber layer defect in the location and size of peripapillary atrophy and is a significantly negative prognostic factor in patients with normal-tension glaucoma.1–2 Branch retinal vein occlusion does not seem to be related to intraocular pressure (IOP) and primary open-angle glaucoma, especially when occurring at an arteriovenous crossing.3 Conversely, in openangle glaucoma patients, Sonnsjo and associates4 noted that the incidence of retinal venous occlusion (10.5%) was higher than in control subjects (1.3%) and that disk hemorrhage was also present in some cases (29 of 1,026 cases). These researchers hypothesized that disk hemorrhage is the thrombosis of very small vessels. However, there has been no report dealing with branch retinal vein occlusion in normal-tension glaucoma patients with disk hemorrhage. From July 2001 to June 2002, during diagnostic workup for normal-tension glaucoma patients in the Glaucoma Clinic of Seoul National University Hospital, 15 cases of normal-tension glaucoma with disk hemorrhage in one eye were detected, four of which showed combined branch retinal vein occlusion in the contralateral eye. Twentyfour hour IOP measurement, fundus examination, retinal nerve fiber layer photography, stereo disk photography, Humphrey visual field analysis, confocal scanning laser tomography, and fluorescein angiography were performed for all four patients. Table 1 shows the clinical characteristics of the four patients. Mean age was 57 ⫾ 10 years (range, 47–71 years). Three patients (75%) had systemic hypertension. Two patients had bilateral normal-tension glaucoma and thus branch retinal vein occlusion in normal-tension glaucoma eyes. Three patients showed occlusion occurring at the arteriovenous crossing and one patient at the optic cup. Mean cup-to-disk ratio ranged from 0.5 to 0.8. There was no significant difference in IOP between the disk hemorrhage eyes and the contralateral eyes with branch retinal vein occlusion. All four patients had bilateral peripapillary atrophy and retinal nerve fiber layer defects collocated with the disk hemorrhage (Figure 1). To the best of our knowledge, this is the first report of disk hemorrhage in normal-tension glaucoma associated with contralateral branch retinal vein occlusion. These cases suggest the possibility that some disk hemorrhages in normal-tension glaucoma may have a pathogenic mechanism in common with branch retinal vein occlusion and may likewise be caused by thrombosis of very small vessels. REFERENCES
1. Sugiyama K, Tomita G, Kitazawa Y, Onda E, Shinohara H, Park KH. The associations of optic disk hemorrhage with retinal nerve fiber layer defect and peripapillary atrophy in
VOL. 137, NO. 2
normal-tension glaucoma. Ophthalmology 1997;104:1926 – 1933. 2. Ishida K, Yamamoto T, Sugiyama K, Kitazawa Y. Disk hemorrhage is a significantly negative prognostic factor in normaltension glaucoma. Am J Ophthalmol 2000;129:707–714. 3. Beaumont PE, Kang HK. Cup-to-disk ratio, intraocular pressure, and primary open-angle glaucoma in retinal venous occlusion. Ophthalmology 2002;109:282. 4. Sonnsjo B, Krakau CE. Arguments for a vascular glaucoma etiology. Acta Ophthalmol 1993;71:433–444.
Autoclavable Wide-angle Contact Lens for Vitreous Surgery Vinay A. Shah, MD, and Kakarla V. Chalam, MD To evaluate an autoclavable self-stabilizing wide-angle contact lens for vitrectomy. DESIGN: Observational study. METHOD: The wide-angle contact lens has two lens pieces within a high temperature-resistant (150 C) plastic casing. The inferior lens with footplates is made of acrylic and the superior of glass. During surgery the lens is used as the self-stabilizing wide-angle contact lens with improved stability on the eye. RESULT: The lens enables the surgeon to address the peripheral retina with less dependence on the assistant. The lens is sterilizable by autoclaving. The field of view of the wide-angle lens is 106 degrees static and 127 degrees dynamic view. CONCLUSION: The autoclavable self-stabilizing wide-angle lens reduces the cost and time for sterilization. (Am J Ophthalmol 2004;137:359 –360. © 2004 by Elsevier Inc. All rights reserved.) PURPOSE:
G
OOD VISUALIZATION OF THE FUNDUS IS CRUCIAL FOR
successful vitreous surgery. Wide-field viewing with an appropriate contact lens is a major advance in this direction. Sterilization of these lenses is traditionally done either by ethylene oxide gas or chemically by glutaraldehyde 2% or povidone iodine 5%.1 Sterilization with steam autoclaving is cost effective, fast, and widely used. However, it cannot be used for presently available wide-angle, self-stabilizing lenses.2 We describe a new autoclavable self-stabilizing, wide-angle lens for vitreous surgery. The wide-angle contact lens (Figure 1, A) has two lens pieces within a high temperature-resistant 302 F (150 C) plastic casing. The inferior part has an acrylic concavoconvex lens with footplates (Figure 1, B; refractive index [RI] 1.51). The concave contact surface has a radius of curvaAccepted for publication July 22, 2003. From the Department of Ophthalmology, University of Florida College of Medicine, Jacksonville, Florida. Inquiries to Kakarla V. Chalam, MD, Department of Ophthalmology, University of Florida College of Medicine, 580 W. 8th Street, Jacksonville, FL 32209; fax: (904) 244-9391; e-mail: [email protected]
BRIEF REPORTS
359
FIGURE 1. (A) Photograph showing the autoclavable self-stabilizing wide-angle contact lens. (B) Photograph of the superior part (X) and the inferior part (Y) of the self-stabilizing, autoclavable wide-angle lens.
After use, parts are detached, cleaned, put in a lens case, and wrapped. Standard cycle of sterilization recommended is 270 F (134 C) for 15 minutes or 250 F (121 C) for 30 minutes. Distilled water is used in the steam sterilizer to avoid deposits on the lens. The flash autoclave allows for immediate use when necessary. The lens can also be sterilized with ethylene oxide gas or with chemicals such as glutaraldehyde 2% or povidone iodine 5%.1 The wide-angle contact lens can be effectively sterilized by autoclaving. The optical surfaces are glass and acrylic, which are high temperature resistant. The casing is made of heat-resistant plastic that can withstand the heat and pressure of steam autoclaving. The lens is reassembled on cooling. The footplates provide better stability, requiring minimal assistance during difficult surgical steps or dynamic viewing. In presence of tight lids, a lateral canthotomy may be necessary. However, holding the lens is less cumbersome for the assistant than it is with a conventional lens because of the increased stability. Fogging is a disadvantage that can be avoided by proper assembly and sufficient cooling or using an intermediate liquid in between the two parts. There are reports on the handheld, irrigating steamsterilizable contact lens.3 To the best of our knowledge, there are no previous reports of an autoclavable wide-angle self-stabilizing lens for vitrectomy.
FIGURE 2. Photograph of the view of the fundus through the lens.
ture (ROC) of 7.7 mm and total cord diameter 17 mm, providing a wide contact surface for stability. The superior biconvex lens is made of glass (Figure 1, B; RI 1.883). The convex superior surface has a ROC of 6.95 mm. The inferior part slides into the superior to make the wide-angle assembly (Figure 1, A). The refractive power of the lens is 150 diopters, magnification 0.39 times, and static field of view (the total visible retina in a single field) 107 degrees; while the dynamic field (total area of the fundus that can be viewed by moving the lens on the cornea) is 127 degrees (Figure 2). The lens is kept on the cornea over a drop of viscoelastic substance. The posterior concavity, footplates, light weight (4 g), suction effect, and small size of the lens keep it stable, allowing better rotation of the globe and dynamic viewing of the retina during surgical manipulation. If required, the lens can be held or supported by an assistant with a conventional lens holder. 360
AMERICAN JOURNAL
REFERENCES
1. Das T, Sharma S, Singh J, Rao V, Chalam KV. Evaluation of glutaraldehyde and povidone iodine for sterilization of widefield contact vitrectomy lenses. Ophthalmic Surg Lasers 2001; 32:300 –304. 2. Shah VA, Chalam KV. Self-stabilizing, wide-angle contact lens for vitreous surgery. Retina. 2003;23:667– 669. 3. Parel JM, Machemer R. Steam-sterilizable fundus contact lenses. Arch Ophthalmol 1981;99:151. OF
OPHTHALMOLOGY
FEBRUARY 2004