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Foreign body episcleral granulomas complicating intravitreal silicone oil tamponade
Foreign Body Episcleral Granulomas Complicating Intravitreal Silicone Oil Tamponade A Clinicopathological Study Sathish Srinivasan, FRCSEd, MRCOphth,1,2 Arvind K. Singh, FRCS, FRCOphth,1 Shrivatsa P. Desai, FRCS, FRCOphth,3 John F. Talbot, FRCS, FRCOphth,4 M. Andrew Parsons, FRCPath5 Purpose: To report two patients with lipid granulomas of the episclera complicating vitrectomy and silicone oil tamponade. Design: Two observational case reports. Intervention: Patient 1, a 41-year-old woman, underwent vitrectomy with silicone oil tamponade for proliferative diabetic retinopathy. Four weeks later, she sought treatment for inflamed episcleral nodules adjacent to one of the sclerostomy sites. The oil was removed and the episcleral nodules were excised. Patient 2, a 33-year-old man, underwent vitrectomy and silicone oil tamponade for tractional retinal detachment. He experienced a painful blind eye with episcleral nodule that required enucleation. Main Outcome Measures: On histopathological analysis, both specimens demonstrated episcleral granulomas caused by silicone oil. Conclusions: Episcleral nodules adjacent to vitrectomy entry sites with silicone oil tamponade may represent lipid granulomas, probably caused by silicone oil leakage from scleral entry ports. Ophthalmology 2003;110: 1837–1840 © 2003 by the American Academy of Ophthalmology.
Intravitreal injection of liquid silicone was first described 40 years ago as an adjunct in the treatment of complicated retinal detachments.1 Since then, there have been several reports on the anterior and posterior segment complications of silicone oil.2–5 Histopathological studies have shown the presence of silicone vacuoles into various ocular tissues.4,5 Intraocular foreign body giant cell reaction and granulomatous response to liquid silicone has been described.6 – 8 To
our knowledge, an episcleral granulomatous response to silicone oil has not been reported. We present two cases of silicone oil-induced episcleral granulomas and discuss their clinical and histopathological features.
Case Reports Patient 1
Originally received: October 21, 2002. Accepted: March 5, 2003. Manuscript no. 220856. 1 Department of Ophthalmology, Ayr Hospital, Ayrshire, United Kingdom. 2 Tennent Institute of Ophthalmology, Gartnavel General Hospital, Glasgow, United Kingdom. 3 Department of Ophthalmology, Doncaster Royal Infirmary, Doncaster, United Kingdom. 4 Department of Ophthalmology, Royal Hallamshire Hospital, Sheffield, United Kingdom. 5 Ophthalmic Sciences Unit, University of Sheffield, Sheffield, United Kingdom. Presented at the joint meeting of the American Academy of Ophthalmology and the Pan-American Association of Ophthalmology, Orlando, Florida, October 2002. None of the authors has any financial or proprietary interest in any of the products described in this paper. Correspondence to Sathish Srinivasan, FRCSEd, MRCOphth, St. Paul’s Eye Unit, Royal Liverpool University Hospital, Prescot Street, Liverpool L7 8XP, United Kingdom. E-mail: [email protected]. © 2003 by the American Academy of Ophthalmology Published by Elsevier Inc.
A 41-year-old white female with myopia and type 1 diabetes mellitus underwent pars plana vitrectomy, membrane peel, endolaser, and silicone oil tamponade (1000 centistokes, medical grade) in the right eye. After the closure of the sclerotomies, liberal washout with balanced salt solution was performed to wash away excess silicone oil. The washout was repeated after the closure of the conjunctiva. On the first postoperative day, the retina appeared attached and the intraocular pressure was normal. Four weeks later, she sought treatment for inflamed episcleral nodules close to the superotemporal sclerostomy site (Fig 1A). The sclerostomy sites were secure. Silicone oil was noted in the anterior chamber, and the intraocular pressure was elevated to 72 mmHg. Because the intraocular pressure failed to respond to medical therapy, silicone oil was removed via pars plana and the nodules were excised. After surgery, the intraocular pressure returned to normal. Histopathological analysis of the episcleral nodule showed granulomatous inflammation surrounding large and small extracellular lipid droplets. Intracellular lipid vacuoles consistent with the presence of silicone oil also were noted (Fig 1B, C). ISSN 0161-6420/03/$–see front matter doi:10.1016/S0161-6420(03)00571-2
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Srinivasan et al 䡠 Silicone Oil Episcleral Granulomas Figure 1. A, Right eye of patient 1 showing inflamed episcleral nodules (arrow heads) in the superotemporal quadrant. Note the suture (arrow) closing the scleral entry site. B, Histologic results of the excised episcleral nodule in patient 1 showing rounded lipid droplets surrounded by granulomas (stain, hematoxylin– eosin; original magnification, ⫻50). C, Higher-power histologic results of the excised episcleral nodule in patient 1 showing rounded lipid droplets (S) surrounded by epithelioid macrophages and multinucleated giant cells (arrows; stain, hematoxylin– eosin; original magnification, ⫻200). D, The enucleated eye of patient 2 showing the largest episcleral lipid deposit (highlighted area, superotemporally), with glistening leaking oil just below. The arrow indicates the superior rectus insertion site near the marker dot. ON ⫽ optic nerve. E, Histologic results of the superotemporal aspect of the right eye of patient 2. Above the sclera, there are numerous episcleral lipid “lakes” (S) with surrounding granulomas. The highlighted box is anterior to the equator and contains the scleral entry site (see F and G; stain, hematoxylin– eosin; original magnification, ⫻25). F, G, Higher-power microscopy of the scleral entry site for patient 2, marked by the intrascleral incarcerated uveal pigment. The polarized light shows the suture material (arrows). Note the surrounding granulomatous inflammation (asterisk; stain, hematoxylin– eosin; original magnification, ⫻50 and ⫻100, respectively). 4™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™
Patient 2 A 21-year-old white male underwent vitrectomy with silicone oil tamponade (1000 centistokes, medical grade) for retinal detachment and proliferative vitreoretinopathy. Surgery was complicated by retinal incarceration into the superotemporal sclerostomy site. After surgery, a shallow retinal detachment persisted. The same procedure was repeated 2 months later with successful attachment of the retina. Eleven years after surgery (at the age of 33 years), he sought treatment for a blind and painful eye, which was enucleated. Macroscopically, there were large episcleral oil-filled “lakes” in the superotemporal quadrant, extending posteriorly from a point just anterior to the equator (Fig 1D). Histologically, there was band keratopathy, anterior synechiae, and long-standing retinal gliosis. The episclera contained prominent large extracellular oil droplets and vesicles (Fig 1E–G). The superotemporal sclerostomy site showed uveal incarceration. (Fig 1F, G). There was some granulomatous inflammation in response to oil and suture material (Fig 1F). Intraocular silicone oil vesicles also were present, often within macrophages, in the collapsed anterior chamber, the angle, the ciliary body, and the choroid (not shown).
Discussion To our knowledge, episcleral (extraocular) silicone oil granulomas have not been described previously, particularly in relation to retinal detachment surgery. The use of silicone (in the form of oils, elastomers, or solids) was first described in ocular and breast surgery in 19621 and in 1963,9 respectively. It was believed to be biologically inert. Recent literature has documented local and systemic reactions to silicone in relation to breast implants.10 In the ophthalmic literature, Cibis11 was the first to describe the histopathological findings in silicone oil-injected human eyes. Of the three eyes in his series, one showed acute aseptic endophthalmitis and the other two showed severe chronic uveitis. Leaver et al2 described 93 eyes with late complications of silicone oil injection and reported light and electron microscopic findings in one eye enucleated 32 months after silicone oil injection. Silicone oil bubbles of various sizes were found in the corneal endothelium, trabecular meshwork, and on the anterior and posterior surface of the lens capsule. Silicone oil vacuoles in the corneal endothelium, iris stroma, anterior chamber angle, retina, and the optic nerve also have been demonstrated.2,5,12
Implantation of solid silicone, in the form of scleral buckles, has been shown to induce a foreign body response (in the form of a local inflammatory reaction and fibrous capsule) in rabbits.13 Parmley et al6 were the first to demonstrate a foreign body giant cell reaction in a human eye enucleated 20 months after intravitreal silicone oil injection; giant cells were demonstrated lining the peripheral cornea, the anterior chamber angle, and the anterior iris surface. They postulated that this was a result of prolonged presence of silicone oil in the eye. In 1985, Travis et al14 reviewed the literature on the use of silicone in humans and reported three additional cases in which significant foreign body giant cell reaction with silicone elastomers or silicone rubbers was seen. Similar foreign body reaction was seen with silicone gel or liquid. They postulated that the impurities or fillers in the silicone elastomers (i.e., the solid form of silicone) were a possible cause of the granulomatous inflammation. To our knowledge, only two reports of an intraocular granulomatous reaction to silicone oil exist. Shaikh et al7 demonstrated a local granulomatous reaction involving the vitreous and subretinal space in a patient with alcoholic cirrhosis who had an enhanced serum immunoglobulin G (IgG) binding to silicones. Budde et al8 described a granulomatous reaction to silicone oil in the optic nerve. Recent public concerns have increased about possible local and systemic reactions to silicone, particularly in relation to breast implants. Some of these patients have been found to have a specific “antipolymer” IgG, as a specific immune response to implanted silicones, perhaps causing intense local inflammatory reactions to implanted silicone materials.10 The exact nature of this enhanced binding of serum IgG to silicone has not been fully elucidated and remains controversial. In some patients, it may serve as a marker for the propensity to develop intense local inflammatory reactions to silicone materials (such as ventriculoperitoneal shunts).15 Of the 49 patients in whom silicone was used in ocular surgery, one was noted to have “antipolymer” IgG, and this patient had a systemic connective tissue disease. It was concluded that this should not alter the clinical use of liquid silicone.16 We did not test our patients for increased serum IgG binding to silicone. We have demonstrated that episcleral granulomas can develop adjacent to vitrectomy entry sites after intravitreal silicone oil tamponade. Further studies are required to elucidate the immunologic basis of this rare complication.
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References 1. Cibis PA, Becker B, Okun E, Cannan S. The use of liquid silicone in retinal detachment surgery. Arch Ophthalmol 1962; 68:590 –9. 2. Leaver PK, Grey RH, Garner A. Silicone oil injection in the treatment of massive preretinal retraction. II. Late complications in 93 eyes. Br J Ophthalmol 1979;63:361–7. 3. Federman JL, Schubert HD. Complications associated with the use of silicone oil in 150 eyes after retina-vitreous surgery. Ophthalmology 1988;95:870 – 6. 4. Knorr HL, Seltsam A, Holbach L, Naumann GO. Intraocular silicone oil tamponade: a clinico-pathologic study of 36 enucleated eyes [in German]. Ophthalmologe 1996;93:130 – 8. 5. Ni C, Wang W, Albert DM, Schepens CL. Intravitreous silicone injection. Histopathologic findings in a human eye after 12 years. Arch Ophthalmol 1983;101:1399 – 401. 6. Parmley VC, Barishak YR, Howes EL Jr, Crawford JB. Foreign-body giant cell reaction to liquid silicone. Am J Ophthalmol 1986;101:680 –3. 7. Shaikh S, Egbert PR, Goldblum RS, Wieland MR. Granulomatous local cell reaction to intravitreal silicone. Arch Ophthalmol 2000;118:1133– 4. 8. Budde M, Cursiefen C, Holbach LM, Naumann GO. Silicone oil-associated optic nerve degeneration. Am J Ophthalmol
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2001;131:392– 4. 9. Cronin TD, Gerow FJ. Augmentation mammoplasty: a new “natural feel” prosthesis. In: Broadbent TR, ed. Transactions of the Third International Congress of Plastic Surgery. Amsterdam: Excerpta Medica Foundation, 1964:41–9. 10. Tenenbaum SA, Rice JC, Espinoza LR, et al. Use of antipolymer antibody assay in recipients of silicone breast implants. Lancet 1997;349:449 –54. 11. Cibis PA. Vitreoretinal Pathology and Surgery in Retinal Detachment. St Louis: C.V. Mosby Co.; 1965; 249 –51. 12. Laroche L, Pavlakis C, Saraux H, Orcel L. Ocular findings following intravitreal silicone injection. Arch Ophthalmol 1983;101:1422–5. 13. D’Hermies F, Korobelnik JF, Savoldelli M, et al. Miragel versus silastic used as episcleral implants in rabbits: an experimental and histopathologic comparative study. Retina 1995;15:62–7. 14. Travis WD, Balogh K, Abraham JL. Silicone granulomas. Report of three cases and review of the literature. Hum Pathol 1985;16:19 –27. 15. Goldblum RM, Pelley RP, O’Donell AA, et al. Antibodies to silicone elastomers and reactions to ventriculoperitoneal shunts. Lancet 1992;340:510 –3. 16. Shaikh S, Morse LS, Goldblum RM, et al. The effect of silicone ocular surgical devises on serum IgG binding to silicones. Am J Ophthalmol 1998;126:798 – 804.
Intravitreal injection of liquid silicone was first described 40 years ago as an adjunct in the treatment of complicated retinal detachments.1 Since then, there have been several reports on the anterior and posterior segment complications of silicone oil.2–5 Histopathological studies have shown the presence of silicone vacuoles into various ocular tissues.4,5 Intraocular foreign body giant cell reaction and granulomatous response to liquid silicone has been described.6 – 8 To
our knowledge, an episcleral granulomatous response to silicone oil has not been reported. We present two cases of silicone oil-induced episcleral granulomas and discuss their clinical and histopathological features.
Case Reports Patient 1
Originally received: October 21, 2002. Accepted: March 5, 2003. Manuscript no. 220856. 1 Department of Ophthalmology, Ayr Hospital, Ayrshire, United Kingdom. 2 Tennent Institute of Ophthalmology, Gartnavel General Hospital, Glasgow, United Kingdom. 3 Department of Ophthalmology, Doncaster Royal Infirmary, Doncaster, United Kingdom. 4 Department of Ophthalmology, Royal Hallamshire Hospital, Sheffield, United Kingdom. 5 Ophthalmic Sciences Unit, University of Sheffield, Sheffield, United Kingdom. Presented at the joint meeting of the American Academy of Ophthalmology and the Pan-American Association of Ophthalmology, Orlando, Florida, October 2002. None of the authors has any financial or proprietary interest in any of the products described in this paper. Correspondence to Sathish Srinivasan, FRCSEd, MRCOphth, St. Paul’s Eye Unit, Royal Liverpool University Hospital, Prescot Street, Liverpool L7 8XP, United Kingdom. E-mail: [email protected]. © 2003 by the American Academy of Ophthalmology Published by Elsevier Inc.
A 41-year-old white female with myopia and type 1 diabetes mellitus underwent pars plana vitrectomy, membrane peel, endolaser, and silicone oil tamponade (1000 centistokes, medical grade) in the right eye. After the closure of the sclerotomies, liberal washout with balanced salt solution was performed to wash away excess silicone oil. The washout was repeated after the closure of the conjunctiva. On the first postoperative day, the retina appeared attached and the intraocular pressure was normal. Four weeks later, she sought treatment for inflamed episcleral nodules close to the superotemporal sclerostomy site (Fig 1A). The sclerostomy sites were secure. Silicone oil was noted in the anterior chamber, and the intraocular pressure was elevated to 72 mmHg. Because the intraocular pressure failed to respond to medical therapy, silicone oil was removed via pars plana and the nodules were excised. After surgery, the intraocular pressure returned to normal. Histopathological analysis of the episcleral nodule showed granulomatous inflammation surrounding large and small extracellular lipid droplets. Intracellular lipid vacuoles consistent with the presence of silicone oil also were noted (Fig 1B, C). ISSN 0161-6420/03/$–see front matter doi:10.1016/S0161-6420(03)00571-2
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Ophthalmology Volume 110, Number 9, September 2003
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Srinivasan et al 䡠 Silicone Oil Episcleral Granulomas Figure 1. A, Right eye of patient 1 showing inflamed episcleral nodules (arrow heads) in the superotemporal quadrant. Note the suture (arrow) closing the scleral entry site. B, Histologic results of the excised episcleral nodule in patient 1 showing rounded lipid droplets surrounded by granulomas (stain, hematoxylin– eosin; original magnification, ⫻50). C, Higher-power histologic results of the excised episcleral nodule in patient 1 showing rounded lipid droplets (S) surrounded by epithelioid macrophages and multinucleated giant cells (arrows; stain, hematoxylin– eosin; original magnification, ⫻200). D, The enucleated eye of patient 2 showing the largest episcleral lipid deposit (highlighted area, superotemporally), with glistening leaking oil just below. The arrow indicates the superior rectus insertion site near the marker dot. ON ⫽ optic nerve. E, Histologic results of the superotemporal aspect of the right eye of patient 2. Above the sclera, there are numerous episcleral lipid “lakes” (S) with surrounding granulomas. The highlighted box is anterior to the equator and contains the scleral entry site (see F and G; stain, hematoxylin– eosin; original magnification, ⫻25). F, G, Higher-power microscopy of the scleral entry site for patient 2, marked by the intrascleral incarcerated uveal pigment. The polarized light shows the suture material (arrows). Note the surrounding granulomatous inflammation (asterisk; stain, hematoxylin– eosin; original magnification, ⫻50 and ⫻100, respectively). 4™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™
Patient 2 A 21-year-old white male underwent vitrectomy with silicone oil tamponade (1000 centistokes, medical grade) for retinal detachment and proliferative vitreoretinopathy. Surgery was complicated by retinal incarceration into the superotemporal sclerostomy site. After surgery, a shallow retinal detachment persisted. The same procedure was repeated 2 months later with successful attachment of the retina. Eleven years after surgery (at the age of 33 years), he sought treatment for a blind and painful eye, which was enucleated. Macroscopically, there were large episcleral oil-filled “lakes” in the superotemporal quadrant, extending posteriorly from a point just anterior to the equator (Fig 1D). Histologically, there was band keratopathy, anterior synechiae, and long-standing retinal gliosis. The episclera contained prominent large extracellular oil droplets and vesicles (Fig 1E–G). The superotemporal sclerostomy site showed uveal incarceration. (Fig 1F, G). There was some granulomatous inflammation in response to oil and suture material (Fig 1F). Intraocular silicone oil vesicles also were present, often within macrophages, in the collapsed anterior chamber, the angle, the ciliary body, and the choroid (not shown).
Discussion To our knowledge, episcleral (extraocular) silicone oil granulomas have not been described previously, particularly in relation to retinal detachment surgery. The use of silicone (in the form of oils, elastomers, or solids) was first described in ocular and breast surgery in 19621 and in 1963,9 respectively. It was believed to be biologically inert. Recent literature has documented local and systemic reactions to silicone in relation to breast implants.10 In the ophthalmic literature, Cibis11 was the first to describe the histopathological findings in silicone oil-injected human eyes. Of the three eyes in his series, one showed acute aseptic endophthalmitis and the other two showed severe chronic uveitis. Leaver et al2 described 93 eyes with late complications of silicone oil injection and reported light and electron microscopic findings in one eye enucleated 32 months after silicone oil injection. Silicone oil bubbles of various sizes were found in the corneal endothelium, trabecular meshwork, and on the anterior and posterior surface of the lens capsule. Silicone oil vacuoles in the corneal endothelium, iris stroma, anterior chamber angle, retina, and the optic nerve also have been demonstrated.2,5,12
Implantation of solid silicone, in the form of scleral buckles, has been shown to induce a foreign body response (in the form of a local inflammatory reaction and fibrous capsule) in rabbits.13 Parmley et al6 were the first to demonstrate a foreign body giant cell reaction in a human eye enucleated 20 months after intravitreal silicone oil injection; giant cells were demonstrated lining the peripheral cornea, the anterior chamber angle, and the anterior iris surface. They postulated that this was a result of prolonged presence of silicone oil in the eye. In 1985, Travis et al14 reviewed the literature on the use of silicone in humans and reported three additional cases in which significant foreign body giant cell reaction with silicone elastomers or silicone rubbers was seen. Similar foreign body reaction was seen with silicone gel or liquid. They postulated that the impurities or fillers in the silicone elastomers (i.e., the solid form of silicone) were a possible cause of the granulomatous inflammation. To our knowledge, only two reports of an intraocular granulomatous reaction to silicone oil exist. Shaikh et al7 demonstrated a local granulomatous reaction involving the vitreous and subretinal space in a patient with alcoholic cirrhosis who had an enhanced serum immunoglobulin G (IgG) binding to silicones. Budde et al8 described a granulomatous reaction to silicone oil in the optic nerve. Recent public concerns have increased about possible local and systemic reactions to silicone, particularly in relation to breast implants. Some of these patients have been found to have a specific “antipolymer” IgG, as a specific immune response to implanted silicones, perhaps causing intense local inflammatory reactions to implanted silicone materials.10 The exact nature of this enhanced binding of serum IgG to silicone has not been fully elucidated and remains controversial. In some patients, it may serve as a marker for the propensity to develop intense local inflammatory reactions to silicone materials (such as ventriculoperitoneal shunts).15 Of the 49 patients in whom silicone was used in ocular surgery, one was noted to have “antipolymer” IgG, and this patient had a systemic connective tissue disease. It was concluded that this should not alter the clinical use of liquid silicone.16 We did not test our patients for increased serum IgG binding to silicone. We have demonstrated that episcleral granulomas can develop adjacent to vitrectomy entry sites after intravitreal silicone oil tamponade. Further studies are required to elucidate the immunologic basis of this rare complication.
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Ophthalmology Volume 110, Number 9, September 2003
References 1. Cibis PA, Becker B, Okun E, Cannan S. The use of liquid silicone in retinal detachment surgery. Arch Ophthalmol 1962; 68:590 –9. 2. Leaver PK, Grey RH, Garner A. Silicone oil injection in the treatment of massive preretinal retraction. II. Late complications in 93 eyes. Br J Ophthalmol 1979;63:361–7. 3. Federman JL, Schubert HD. Complications associated with the use of silicone oil in 150 eyes after retina-vitreous surgery. Ophthalmology 1988;95:870 – 6. 4. Knorr HL, Seltsam A, Holbach L, Naumann GO. Intraocular silicone oil tamponade: a clinico-pathologic study of 36 enucleated eyes [in German]. Ophthalmologe 1996;93:130 – 8. 5. Ni C, Wang W, Albert DM, Schepens CL. Intravitreous silicone injection. Histopathologic findings in a human eye after 12 years. Arch Ophthalmol 1983;101:1399 – 401. 6. Parmley VC, Barishak YR, Howes EL Jr, Crawford JB. Foreign-body giant cell reaction to liquid silicone. Am J Ophthalmol 1986;101:680 –3. 7. Shaikh S, Egbert PR, Goldblum RS, Wieland MR. Granulomatous local cell reaction to intravitreal silicone. Arch Ophthalmol 2000;118:1133– 4. 8. Budde M, Cursiefen C, Holbach LM, Naumann GO. Silicone oil-associated optic nerve degeneration. Am J Ophthalmol
1840
2001;131:392– 4. 9. Cronin TD, Gerow FJ. Augmentation mammoplasty: a new “natural feel” prosthesis. In: Broadbent TR, ed. Transactions of the Third International Congress of Plastic Surgery. Amsterdam: Excerpta Medica Foundation, 1964:41–9. 10. Tenenbaum SA, Rice JC, Espinoza LR, et al. Use of antipolymer antibody assay in recipients of silicone breast implants. Lancet 1997;349:449 –54. 11. Cibis PA. Vitreoretinal Pathology and Surgery in Retinal Detachment. St Louis: C.V. Mosby Co.; 1965; 249 –51. 12. Laroche L, Pavlakis C, Saraux H, Orcel L. Ocular findings following intravitreal silicone injection. Arch Ophthalmol 1983;101:1422–5. 13. D’Hermies F, Korobelnik JF, Savoldelli M, et al. Miragel versus silastic used as episcleral implants in rabbits: an experimental and histopathologic comparative study. Retina 1995;15:62–7. 14. Travis WD, Balogh K, Abraham JL. Silicone granulomas. Report of three cases and review of the literature. Hum Pathol 1985;16:19 –27. 15. Goldblum RM, Pelley RP, O’Donell AA, et al. Antibodies to silicone elastomers and reactions to ventriculoperitoneal shunts. Lancet 1992;340:510 –3. 16. Shaikh S, Morse LS, Goldblum RM, et al. The effect of silicone ocular surgical devises on serum IgG binding to silicones. Am J Ophthalmol 1998;126:798 – 804.