Incidence and Management of Glaucoma after Intravitreal Silicone Oil Injection for Complicated Retinal Detachments Quang H. Nguyen, MD, Mary Ann Lloyd, MD, Dale K. Heuer, MD, George Baerveldt, MD, Don S. Minckler, MD, John S. Lean, MD, Peter E. Liggett, MD Background: Intravitreal silicone oil injection used for managing complicated retinal detachments can be associated with elevated intraocular pressure (lOP). This study was undertaken to determine the incidence of glaucoma in patients who underwent silicone oil injection, as well as to evaluate the effectiveness of medical and surgical therapy in patients in whom glaucoma developed. Methods: The postoperative courses of 50 eyes of 47 consecutive patients who underwent pars plana vitrectomy and silicone oil injection for the management of complicated retinal detachments were reviewed retrospectively. The outcomes of patients who underwent silicone oil removal and/or glaucoma surgery also were evaluated. Results: The mean overall postoperative lOP before any glaucoma surgery was 16.7 ± 9.3 mmHg (range, 0 to 45 mmHg), with a mean follow-up of 16.6 ± 12.1 months (range, 2 to 51 months). Twenty-four (48%) eyes had postoperative lOPs of at least 25 mmHg and lOP elevations of at least 10 mmHg above the preoperative levels. Twentyone (42%) eyes underwent complete removal of silicone oil and/or glaucoma surgery to effect lOP control. The lOPs were controlled to 21 mmHg or less (but> 5 mmHg) in 8 of 14 eyes that underwent removal of silicone oil alone, in 3 of 5 eyes that underwent Molteno implantation, and in 1 eye that underwent Nd:YAG transscleral cyclophotocoagulation, but not in 1 eye that underwent a modified Schocket procedure (mean follow-up, 13.5 ± 11.0 months; range, 0.2 to 33 months). Conclusion: Intraocular pressure elevation is a common occurrence after intravitreal silicone oil injection. The underlying mechanism may often be multifactorial in nature. Patients in whom uncontrolled lOP develops may benefit from aggressive medical and/ or surgical treatment with silicone oil removal, glaucoma implants, or cyclodestructive procedures. Ophthalmology 1992;99: 1520-1526
Originally received: April 2, 1992. Revision accepted: June 12, 1992. From the Department of Ophthalmology, University of Southern California School of Medicine and the Doheny Eye Institute, Los Angeles. Dr. Lloyd is now also with the Department of Veterans Affairs Outpatient Clinic, Los Angeles.
Supported in part by the Foundation for Glaucoma Research, San Francisco, California, National Glaucoma Research, a program of the American Health Assistance Foundation, Beltsville, Maryland, and Research to Prevent Blindness, Inc, New York, New York. The authors have no financial interest in Molteno implants. Dr. Baerveldt does have a financial interest in another glaucoma implant manufactured by another company.
Dr. Lean is now in private practice in Santa Ana. Dr. Liggett is now with the Department of Ophthalmology, Yale University School of Medicine, New Haven.
The views expressed herein are those of the authors and do not reflect the official policy or position of the U.S. Government.
Presented in part as a poster at the American Academy of Ophthalmology Annual Meeting, Anaheim, October 1991.
Reprint requests to Mary Ann Lloyd, MD, Doheny Eye Institute, 1450 San Pablo St, Los Angeles, CA 90033.
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Nguyen et al . Intravitreal Silicone Oil Injection Intravitreal silicone oil injection can be useful in the management of complicated retinal detachments. Because silicone oil can internally tamponade the retina, it can effect anatomic reattachment even in the presence of proliferative vitreoretinopathy. However, intravitreal silic()ne oil injection has been associated with a high incidence of complications, one of the most common of which is a transient or sometimes permanent intraocular pressure (lOP) elevation. We retrospectively reviewed the postoperative lOP courses of patients who underwent intravitreal silicone oil injection after complete pars plana vitrectomy. This study was undertaken to determine the incidence of glaucoma and the outcomes of medical and surgical glaucoma therapy in patients who underwent silicone oil injection. Possible mechanisms underlying the development of glaucoma after silicone oil injection are discussed.
Subjects and Methods Forty-seven consecutive patients underwent pars plana vitrectomy and silicone oil injection for the management of complicated retinal detachments as participants in the Adatomed Silicone Oil Study at the Doheny Eye Institute between November 11, 1986 and January 4, 1991. Three patients underwent bilateral pars plana vitrectomy and silicone oil injection; results of both eyes have been included in this report. The retinal surgeries were performed by two surgeons (JSL or PEL), and the glaucoma procedures were performed by three surgeons (GB, DKH, or DSM). All patients gave informed consent. The silicone study protocol was approved by the Los Angeles County/ University of Southern California Medical Center Institutional Review Board (research protocol #05741). All patient records were retrospectively reviewed for patient demographic, preoperative, intraoperative, and postoperative data, the most current postoperative data being obtained from the referring ophthalmologists' offices for patients who could not return to the Doheny Eye Institute for evaluation. Elevated lOP was defined before reviewing the charts as any postoperative lOP of at least 25 mmHg that also was at least 10 mmHg above the preoperative lOP level. For those patients who underwent surgery to control their lOPs, the categories for surgical outcome were also defined prior to reviewing the charts (Table I). The final postoperative visual acuities and lOPs were those from each patient's most recent examination.
For those patients who lost light perception, the final dates were recorded when the patients were first noted to have lost light perception.
Surgical Procedures All patients underwent standard three-port pars plana vitrectomy, membrane segmentation, and additional procedures (such as scleral buckling) as appropriate for the retinal pathology, followed by silicone oil injection. Before silicone oil injection, inferior peripheral iridectomies were created in those patients with aphakia and pseudophakia who had sufficient iris present. Glaucoma surgical procedures performed included one- or two-stage single-plate Molteno implantation, modified Schocket procedure, and Nd:YAG transscleral cyclophotocoagulation. The basic procedure for Molteno implantation has been described previously, I with a few modifications added in this group of patients. A peritomy was performed at the limbus, and blunt dissection was used to free space posteriorly between the rectus muscles. In eyes that had scleral buckles in place, the Molteno plates were secured to the sclera or bands with 5-0 polyester fiber suture through the two anterior fixation holes. Implantations were most frequently performed inferiorly with the tubes (which were ligated with absorbable suture during one-stage procedures) inserted through 22- or 23-gauge needle tracts at the inferior limbus (rather than the pars plana) to minimize postoperative silicone drainage through the tubes. Donor glycerin-preserved scleral grafts were applied over the ends of the tubes adjacent to the limbus, and conjunctiva and Tenon's capsule were closed at the limbus with 7-0 or 8-0 polyglactin mattress sutures that were run posteriorly, closing the relaxing incisions in a single layer. Dexamethasone phosphate (12 mg), gentamicin sulfate (20 mg), and (in some cases) vancomycin hydrochloride (20 mg) were injected subconjunctivally at the conclusion of the procedures; postoperatively, patients were treated with topical I % prednisolone acetate or phosphate for several months and topical antibiotics for I to 2 weeks. The modified Schocket procedure was performed through a fornix-based conjunctival opening. Blunt dissection was used to free conjunctiva and Tenon's layers from the previously placed 280 band in the inferior temporal quadrant. The capsule surrounding the encircling element was incised and a 23-gauge needle was used to
Table 1. Categories of Glaucoma Surgical Outcome Complete Success Qualified Success Qualified Failure Complete Failure lOP
6 mmHg ~ lOP ~ 21 mmHg without medication 6 mmHg ~ lOP ~ 21 mmHg with medication lOP> 21 mmHg Further glaucoma surgery (or recommendation thereof), hypotony, devastating complication, or loss of light perception
= intraocular pressure.
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Ophthalmology Volume 99, Number 10, October 1992 Table 2. Data Summary (50 Eyes of 47 Patients) Age (yrs): Range Mean ± SD Lens Status: Aphakic Phakic Retinal Detachment Associated with: Proliferative vitreoretinopathy (PVR) Cytomegalovirus retinitis Proliferative diabetic retinopathy (non-PVR) Giant retinal tear Coloboma Massive choroidal hemorrhage Recurrent retinal detachment Glaucoma Antedating Any Ocular Surgery Congenital Open-angle Angle-closure Neovascular Preoperative lOP (mmHg): Range Mean ± SD Preoperative Antiglaucoma Medication 1 Medication 2 Medications Prior Pars Plana Vitrectomy with Gas and/or Oil Injection Surgical Procedures: Pars plana vitrectomy with silicone oil Scleral buckle (including those placed previously) Peripheral iridectomy Length of Follow-up (mos)*: Range Mean ± SD Postoperative lOP (mmHg)": Range Mean ± SD Postoperative lOP Elevationt Postoperative Antiglaucoma Medication: Temporaryi' 1 Medication 2 Medications 3 Medications Chronic§ 1 Medication 2 Medications 3 Medications Visual Outcome: Eyes without lOP elevation Better II Same~
Worse"" Eyes with lOP elevationtt Better Same Worse Complications: Phthisis bulbi Corneal decompensation Oil infiltrating anterior chamber Rubeosis iridis
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7-80 47.6 ± 21.3 37 (74%) 13 (26%) 35 (70%) 7 (14%) 2(4%) 2(4%) 2(4%) 1 (2%) 1 (2%) 6 (12%) 2(4%) 2(4%) 1 (2%) 1 (2%) 1-22 10.7 ± 5.1 9 (18%) 6(12%) 3(6%) 20 (40%) 50 (100%) 32 (64%) 21 (42%) 2-51 16.6 ± 12.1 0-45 16.7 ± 9.3 24 (48%) 32 (64%) 13 (26%) 14 (28%) 5 (10%) 16 (32%) 11 (22%) 4(8%) 1 (2%) 26 (52%) 10 (20%) 9(18%) 7 (14%) 24 (48%) 8 (16%) 8(16%) 8(16%) 7 (14%) 6 (12%) 6(12%) 3(6%)
Nguyen et al . Intravitreal Silicone Oil Injection
Table 2.
(continued)
SD = standard deviation; PVR = proliferative vitreoretinopathy; lOP • Before silicone oil removal or glaucoma surgery.
= intraocular pressure .
t Postoperative lOP at least 25 mmHg and elevated at least 10 mmHg above preoperative level. t Duration of glaucoma therapy was at least one to five weeks. § Duration of glaucoma therapy was the entire course of follow-up or until surgery was performed to lower the lOP.
II Postoperative visual acuity at least two lines better than preoperative visual acuity. ~
Postoperative visual acuity within one line of preoperative visual acuity .
•• Postoperative visual acuity at least two lines worse than preoperative visual acuity.
tt Visual acuities for those eyes that underwent surgery to lower the lOPs are final acuities after surgery was performed.
create a tract in the capsule through which a silicone tube was passed and secured to the buckling element. The capsule was closed with 8-0 polyglactin suture, and irrigation of the potential space inside the capsule was performed through the tube. The tube insertion, donor scleral graft, conjunctival closure, subconjunctival medications, and postoperative medications were similar to those with Molteno implantation. Nd:YAG transscleral cyclophotocoagulation was performed on one patient. A Shields lens was placed after the patient had received retrobulbar anesthesia, and a total of 36 spots were applied approximately 1.0 to 1.5 mm posterior to the limbus over 360 0 , sparing the 1 clock hour around both the 3-0'clock and 9-0'clock positions. The patient received a topical combination of fluorometholone and sulfacetamide sodium for several weeks after surgery.
Results Demographic, preoperative, intraoperative, and postoperative data are summarized in Table 2. The patients' ages ranged from 7 to 80 years (mean ± standard deviation, 47.6 ± 21.3 years). The mean overall follow-up for patients before their having undergone silicone oil removal or glaucoma surgery was 16.6 ± 12.1 months (range, 2 to 51 months), and the mean follow-up for those patients who underwent surgical procedures to lower their lOPs was 13.5 ± 11.0 months (range, 0.2 to 33 months). The follow-up periods for five patients were limited by their deaths from human immunodeficiency virus infection or other causes unrelated to their eye surgeries. All patients had complicated retinal detachments that were associated with the following conditions: 35 (70%) eyes with proliferative vitreoretinopathy, 7 (14%) eyes with cytomegalovirus retinitis, 2 (4%) eyes each with severe proliferative diabetic retinopathy, giant retinal tears, and colobomas, and 1 (2%) eye each with massive choroidal hemorrhage and recurrent retinal detachment. Thirtyseven eyes were aphakic, and 20 eyes had undergone previous pars plana vitrectomy with gas-fluid exchange or silicone oil injection in attempts to effect retinal reattach-
ment. Eighteen (36%) eyes had previously placed scleral buckles, and 14 (28%) eyes underwent scleral buckling at the time of silicone oil injection. Inferior peripheral iridectomies were performed at the time of oil injection in 21 (42%) eyes. Six (12%) eyes of 6 patients had a diagnosis of glaucoma antedating silicone oil injection (2 patients each had congenital glaucomas and open-angle glaucomas, and 1 patient each had neovascular and secondary angle-closure glaucomas); 3 other patients who had elevated lOPs without diagnoses of glaucoma also were using antiglaucoma medications preoperatively. Twenty-four (48%) eyes overall had postoperative lOPs of at least 25 mmHg and lOP increases of at least 10 mmHg above the preoperative levels. The preoperative lOPs ranged from 1 to 22 mmHg (mean ± standard deviation, 10.7 ± 5.1 mmHg), and the final lOPs before silicone oil removal or glaucoma surgery ranged from 0 to 45 mmHg (mean ± standard deviation, 16.7 ± 9.3 mmHg). Thirty-two (64%) eyes received antiglaucoma medications at least temporarily (from 1 to 5 weeks after surgery), and 16 of those eyes chronically received medications (for the duration offollow-up or until glaucoma surgery was performed) to control lOP. Silicone oil removal alone was performed on 14 eyes, and glaucoma surgery (with or without oil removal) was performed on 7 eyes with medically uncontrollable lOP. The outcomes of these eyes are presented in Table 3. Among the eyes that had silicone oil removal alone, lOP was controlled in eight eyes, and among the eyes that underwent a glaucoma procedure (with or without oil removal), lOP was controlled in four eyes. Of the nine eyes receiving antiglaucoma medications before silicone oil injection, one eye had no postoperative lOP elevation, two eyes had transient postoperative lOP elevations, three eyes received chronic antiglaucoma medical therapy, and three eyes underwent Molteno implantation (two of these eyes were categorized as qualified successes and one eye as a qualified failure). In our series overall, the postoperative visual acuities remained within 1 line of the preoperative visual acuities or improved in 35 (70%) eyes. Among the 24 eyes with lOP elevations (including the eyes on which glaucoma surgery was performed), the final postoperative visual
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Ophthalmology Volume 99, Number 10, October 1992 Table 3. Data Summary of Eyes Undergoing Surgery for Glaucoma (21 Eyes of 18 Patients) Surgical Procedures to Control lOP Silicone oil removal alone· Glaucoma procedurest Molteno implantation Modified Schocket procedure Nd:YAG laser cyclophotocoagulation Preoperative lOP (mmHg): Range Mean ± SD Postoperative lOP (mmHg): Range Mean ± SD Length of Follow-up (mos): Range Mean ± SD Surgical Outcome: Complete silicone oil removal alone Success Complete Qualified Failure Qualified Completer Molteno implantation Success Complete§ Qualified II Failure Qualified1T Complete·· Modified Schocket procedure Qualified failure tt Nd:YAG transscleral cyclophotocoagulation Complete success lOP
21 (42%) 14 (28%)
7 (14%)
5 (10%) 1 (2%)
1 (2%)
15-45
27.0 ± 7.3 4-31 15.8 ± 7.7 0.2-33
13.5 ± 11.0
14 (100%) 8 (57%)
7 (50%)
1 (7%) 6(43%) 0(0%) 6 (43%) 5 (100%) 3(60%) 1 (20%) 2 (40%) 2(40%)
1 (20%) 1 (20%) 1 (100%) 1 (100%) 1 (100%) 1 (100%)
= intraocular pressure; SD = standard deviation.
• All eyes had oil removed within three months of injection.
t One eye each that underwent Molteno implantation, modified Schocket procedure, and Nd:YAG transscleral cyclophotocoagulation also had silicone oil removed previously. t
Three eyes underwent glaucoma procedures, and three eyes lost light perception because of retinal redetachment associated with cytomegalovirus retinitis. § The eye underwent one-stage single-plate Molteno implantation.
II Both eyes underwent one-stage single-plate Molteno implantations. 11 The eye underwent two-stage single-plate Molteno implantation. The final lOP was 23 mmHg but considered adequately controlled in this eye. •• The eye underwent two consecutive two-stage single-plate Molteno implantations and lost light perception because of retinal necrosis associated with severe proliferative diabetic retinopathy.
tt The final lOP was 23 mmHg but considered adequately controlled in this eye.
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acuities remained the same or improved in 16 eyes. All patients who lost light perception did so primarily because of retinal redetachment, ischemia, or necrosis rather than uncontrolled lOP. The complications of silicone oil in this group of patients are summarized in Table 2. Seven (14%) eyes became phthisical. Six (12%) eyes developed corneal decompensation after undergoing silicone oil injection, and penetrating keratoplasty was subsequently performed on them. Oil infiltrated the anterior chambers of 6 (12%) eyes, none of which developed glaucoma. Three eyes (6%) developed postoperative rubeosis iridis, but not neovascular glaucoma. One eye that underwent two consecutive two-stage single-plate Molteno implantations developed a massive anterior chamber fibrin reaction that occluded one tube, which was subsequently cleared by intracameral tissue plasminogen activator. One patient who underwent one-stage single-plate Molteno implantation had oil in the tube tip that did not impair aqueous flow.
Discussion Although the anatomical and visual results obtained from intravitreal silicone oil injection used to manage complicated retinal detachments can be encouraging, late complications may preclude satisfactory long-term outcomes?,3 Although glaucoma is the second most common postoperative adverse occurrence after silicone oil injection (ranging from 15% to 22%),4-7 the mechanisms underlying its development remain controversial. deCorral and colleagues8 have shown that lOP elevation associated with silicone oil injection is independent of systemic conditions such as diabetes mellitus. In 1967, Watzke 2 described the occurrence of postoperative glaucoma after silicone oil injection and indicated that visible oil in the anterior chamber need not necessarily be present when the lOP is elevated. The mechanism for lOP elevation is indeed unclear, as Laroche and co-workers9 noted normal lOPs even when silicone globules were present in the angle. As Sugar and Okamura JO also pointed out, elevated lOP in the presence of silicone oil may be masked by ciliary body detachment from cyclitic membranes. Weinberg and colleagues!! reported elevated lOP after pars plana vitrectomy alone, attributing it to neovascularization, erythroclasis, hemorrhage, hemolysis, or phacolysis, Intraocular pressure elevation also may be due to peripheral anterior synechiae and/or inflammation. 8 In addition, we have seen that silicone oil may become emulsified and enter the anterior chamber (Fig 1), and postulate that it may sometimes impede the drainage of aqueous through the trabecular meshwork. Twenty-four (48%) eyes that underwent pars plana vitrectomy with silicone oil injection in our series had postoperative lOPs of at least 25 mmHg and lOP increases of at least 10 mmHg above the preoperative levels, occurring as early as the first postoperative day. Thirty-two
Nguyen et al . Intravitreal Silicone Oil Injection
Figure 1. Emulsified silicone oil in the anterior chamber after intravitreal injection for repair of a complicated retinal detachment.
(64%) eyes were receiving antiglaucoma medications for at least 1 to 5 weeks after surgery to control the lOPs; 16 of those eyes required chronic medications. Our incidence of glaucoma is higher than those previously reported; the reasons for this finding are unclear but may be related to our patients having had more complex pathology or our definition of glaucoma differing from those in other studies. In any case, given the relatively high incidences of glaucoma after intravitreal silicone oil injection noted in several studies, patients should be closely monitored for postoperative lOP spikes. IflOP elevation occurs, it should probably be treated aggressively to prevent further ischemia to the retina and optic nerve. As 8 of 9 (89%) eyes treated for elevated preoperative lOP had some amount of postoperative lOP elevation (3 of these eyes later underwent glaucoma surgery), our data suggest that patients with elevated lOPs before undergoing silicone oil injection may be particularly at risk for developing elevated postoperative lOP. In our series, 14 (28%) eyes with uncontrolled postoperative lOPs underwent complete silicone oil removal. Furthermore, seven patients (including three who previously had silicone oil removed) underwent glaucoma surgery to attempt lOP control. Because traditional filtering surgery is technically difficult because of conjunctival scarring from the retinal surgery and carries a poor prognosis in eyes having had multiple surgeries, artificial drainage devices or cyclodestructive procedures may be the most appropriate means to lower medically uncontrollable lOPs associated with intravitreal silicone oil. Three of the five eyes that underwent· Molteno implantation and the one eye that underwent Nd:YAG transscleral cyclophotocoagulation achieved lOP control; the one eye that underwent a modified Schocket procedure did not achieve a final lOP of 21 mmHg or less. However, relatively few patients underwent glaucoma procedures in our series, and additional studies are needed to determine which treatment modalities are most effective in
managing glaucoma in patients with intravitreal silicone oil. Among the 21 eyes in this series on which surgery was performed to manage elevated lOPs, all eyes either had scleral buckles and/or lacked intraoperative peripheral iridectomies (because the eyes were phakic or had inadequate amounts of iris present). Although the role of these factors in the development of glaucoma in our patients is uncertain, we re-emphasize the need for performing inferior peripheral iridectomies in aphakic and pseudophakic eyes undergoing intravitreal silicone oil injection, as Ando!2 has suggested, because they may prevent pupillary block by allowing silicone in the anterior chamber to return to the posterior chamber, and aqueous to flow from the posterior to the anterior chamber. In addition, a scleral buckle can impede outflow from the episcleral veins, thereby contributing to inadequate drainage of aqueous from Schlemm's canal, as well as inadequate venous drainage of the ciliary body, making it edematous and more likely to obstruct the angle. A variety of postoperative complications, including phthisis bulbi, occurred in this series, both in eyes that underwent glaucoma surgery and those that did not. Because these eyes frequently had complex pathology, the complications were often difficult to attribute to one etiology. Corneal edema, one of the most frequent adverse occurrences in our series, also has been reported to be the third most common complication in other series6 and is believed to be the result of corneal endothelial decompensation. All six of our patients who had corneal decompensation had oil in contact with the endothelium. Haut and co-workers! 3 reported that approximately 40% ofpatients who developed glaucoma associated with silicone oil injection had oil in the anterior chamber. In our series, 12% of eyes had silicone oil infiltrating the anterior chamber, but none of them developed glaucoma. Three eyes in our series developed rubeosis iridis, but none of them developed neovascular glaucoma, which is consistent with deCorral and colleagues' report. 8 Fourteen percent of the eyes in our series became phthisical; this rate is also somewhat consistent with a report by Weinberg et all! in which 1 of 5 eyes (20%) became phthisical after silicone oil injection. Glaucoma surgery itself was associated with relatively few complications and did not appear to contribute to ophthalmic morbidity overall. In summary, lOP elevation is a common occurrence after intravitreal silicone oil injection used in the management of complicated retinal detachments. The underlying mechanism is often unclear, and may frequently be multifactorial in nature. Patients should be monitored closely for the development of elevated postoperative lOP, especially if they have a history of elevated preoperative lOP, and they may benefit from aggressive medical and/ or surgical treatment of glaucoma with silicone oil removal, glaucoma implants, or cyclodestructive procedures to avoid additional optic nerve damage. Acknowledgment. The authors thank Thomas Chu, MD,
PhD, for providing the photograph.
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Ophthalmology Volume 99, Number 10, October 1992
References 8. 1. Minckler OS, Heuer OK, Hasty B, et al. Clinical experience with the single-plate Molteno implant in complicated glaucomas. Ophthalmology 1988;95:1181-8. 2. Watzke RC. Silicone retinopiesis for retinal detachment. A long-term clinical evaluation. Arch Ophthalmol 1967;77: 185-96. 3. Kanski 11, Daniel R. Intravitreal silicone injection in retinal detachment. Br J Ophthalmol 1973;57:542-5. 4. Alexandridis E, Daniel H. Results of silicone oil injection into the vitreous. Dev Ophthalmol 1981 ;2:24-7. 5. Grey RHB, Leaver PK. Results of silicone oil injection in massive preretinal retraction. Trans Ophthalmol Soc UK 1977;97 :238-41. 6. Leaver PK, Grey RHB, Garner A. Complications following silicone-oil injection. Mod Probl Ophthalmol 1979;20: 290-4. 7. Ni C, Wang W-J, Albert OM, Schepens CL. Intravitreous
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9. 10. II. 12. 13.
silicone injection. Histologic findings in a human eye after 12 years. Arch Ophthalmol 1983;101:1399-1401. deCorral LR, Cohen SB, Peyman GA. Effect of in trav itreal silicone oil on intraocular pressure. Ophthalmic Surg 1987;18:446-9. Laroche L, Pavlakis C, Saraux H, Orcel L. Ocular findings following intravitreal silicone injection. Arch Ophthalmol 1983; 101 :1422-5. Sugar HS, Okamura 10. Ocular findings six years after intravitreal silicone injection. Arch Ophthalmol 1976;94: 612-5. Weinberg RS, Peyman GA, Huamonte FV. Elevation of intraocular pressure after pars plana vitrectomy. Albrecht Von Graefes Arch Klin Exp Ophthalmol 1976;200: 157 -61 . Ando F. Intraocular hypertension resulting from pupillary block by silicone oil [letter]. Am J Ophthalmol 1985;99: 87-8. Haut J, Ullern M, Chermet M, Van Effenterre G. Complications of intraocular injections of silicone combined with vitrectomy. Ophthalmologica 1980; 180:29-35.
Originally received: April 2, 1992. Revision accepted: June 12, 1992. From the Department of Ophthalmology, University of Southern California School of Medicine and the Doheny Eye Institute, Los Angeles. Dr. Lloyd is now also with the Department of Veterans Affairs Outpatient Clinic, Los Angeles.
Supported in part by the Foundation for Glaucoma Research, San Francisco, California, National Glaucoma Research, a program of the American Health Assistance Foundation, Beltsville, Maryland, and Research to Prevent Blindness, Inc, New York, New York. The authors have no financial interest in Molteno implants. Dr. Baerveldt does have a financial interest in another glaucoma implant manufactured by another company.
Dr. Lean is now in private practice in Santa Ana. Dr. Liggett is now with the Department of Ophthalmology, Yale University School of Medicine, New Haven.
The views expressed herein are those of the authors and do not reflect the official policy or position of the U.S. Government.
Presented in part as a poster at the American Academy of Ophthalmology Annual Meeting, Anaheim, October 1991.
Reprint requests to Mary Ann Lloyd, MD, Doheny Eye Institute, 1450 San Pablo St, Los Angeles, CA 90033.
1520
Nguyen et al . Intravitreal Silicone Oil Injection Intravitreal silicone oil injection can be useful in the management of complicated retinal detachments. Because silicone oil can internally tamponade the retina, it can effect anatomic reattachment even in the presence of proliferative vitreoretinopathy. However, intravitreal silic()ne oil injection has been associated with a high incidence of complications, one of the most common of which is a transient or sometimes permanent intraocular pressure (lOP) elevation. We retrospectively reviewed the postoperative lOP courses of patients who underwent intravitreal silicone oil injection after complete pars plana vitrectomy. This study was undertaken to determine the incidence of glaucoma and the outcomes of medical and surgical glaucoma therapy in patients who underwent silicone oil injection. Possible mechanisms underlying the development of glaucoma after silicone oil injection are discussed.
Subjects and Methods Forty-seven consecutive patients underwent pars plana vitrectomy and silicone oil injection for the management of complicated retinal detachments as participants in the Adatomed Silicone Oil Study at the Doheny Eye Institute between November 11, 1986 and January 4, 1991. Three patients underwent bilateral pars plana vitrectomy and silicone oil injection; results of both eyes have been included in this report. The retinal surgeries were performed by two surgeons (JSL or PEL), and the glaucoma procedures were performed by three surgeons (GB, DKH, or DSM). All patients gave informed consent. The silicone study protocol was approved by the Los Angeles County/ University of Southern California Medical Center Institutional Review Board (research protocol #05741). All patient records were retrospectively reviewed for patient demographic, preoperative, intraoperative, and postoperative data, the most current postoperative data being obtained from the referring ophthalmologists' offices for patients who could not return to the Doheny Eye Institute for evaluation. Elevated lOP was defined before reviewing the charts as any postoperative lOP of at least 25 mmHg that also was at least 10 mmHg above the preoperative lOP level. For those patients who underwent surgery to control their lOPs, the categories for surgical outcome were also defined prior to reviewing the charts (Table I). The final postoperative visual acuities and lOPs were those from each patient's most recent examination.
For those patients who lost light perception, the final dates were recorded when the patients were first noted to have lost light perception.
Surgical Procedures All patients underwent standard three-port pars plana vitrectomy, membrane segmentation, and additional procedures (such as scleral buckling) as appropriate for the retinal pathology, followed by silicone oil injection. Before silicone oil injection, inferior peripheral iridectomies were created in those patients with aphakia and pseudophakia who had sufficient iris present. Glaucoma surgical procedures performed included one- or two-stage single-plate Molteno implantation, modified Schocket procedure, and Nd:YAG transscleral cyclophotocoagulation. The basic procedure for Molteno implantation has been described previously, I with a few modifications added in this group of patients. A peritomy was performed at the limbus, and blunt dissection was used to free space posteriorly between the rectus muscles. In eyes that had scleral buckles in place, the Molteno plates were secured to the sclera or bands with 5-0 polyester fiber suture through the two anterior fixation holes. Implantations were most frequently performed inferiorly with the tubes (which were ligated with absorbable suture during one-stage procedures) inserted through 22- or 23-gauge needle tracts at the inferior limbus (rather than the pars plana) to minimize postoperative silicone drainage through the tubes. Donor glycerin-preserved scleral grafts were applied over the ends of the tubes adjacent to the limbus, and conjunctiva and Tenon's capsule were closed at the limbus with 7-0 or 8-0 polyglactin mattress sutures that were run posteriorly, closing the relaxing incisions in a single layer. Dexamethasone phosphate (12 mg), gentamicin sulfate (20 mg), and (in some cases) vancomycin hydrochloride (20 mg) were injected subconjunctivally at the conclusion of the procedures; postoperatively, patients were treated with topical I % prednisolone acetate or phosphate for several months and topical antibiotics for I to 2 weeks. The modified Schocket procedure was performed through a fornix-based conjunctival opening. Blunt dissection was used to free conjunctiva and Tenon's layers from the previously placed 280 band in the inferior temporal quadrant. The capsule surrounding the encircling element was incised and a 23-gauge needle was used to
Table 1. Categories of Glaucoma Surgical Outcome Complete Success Qualified Success Qualified Failure Complete Failure lOP
6 mmHg ~ lOP ~ 21 mmHg without medication 6 mmHg ~ lOP ~ 21 mmHg with medication lOP> 21 mmHg Further glaucoma surgery (or recommendation thereof), hypotony, devastating complication, or loss of light perception
= intraocular pressure.
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Ophthalmology Volume 99, Number 10, October 1992 Table 2. Data Summary (50 Eyes of 47 Patients) Age (yrs): Range Mean ± SD Lens Status: Aphakic Phakic Retinal Detachment Associated with: Proliferative vitreoretinopathy (PVR) Cytomegalovirus retinitis Proliferative diabetic retinopathy (non-PVR) Giant retinal tear Coloboma Massive choroidal hemorrhage Recurrent retinal detachment Glaucoma Antedating Any Ocular Surgery Congenital Open-angle Angle-closure Neovascular Preoperative lOP (mmHg): Range Mean ± SD Preoperative Antiglaucoma Medication 1 Medication 2 Medications Prior Pars Plana Vitrectomy with Gas and/or Oil Injection Surgical Procedures: Pars plana vitrectomy with silicone oil Scleral buckle (including those placed previously) Peripheral iridectomy Length of Follow-up (mos)*: Range Mean ± SD Postoperative lOP (mmHg)": Range Mean ± SD Postoperative lOP Elevationt Postoperative Antiglaucoma Medication: Temporaryi' 1 Medication 2 Medications 3 Medications Chronic§ 1 Medication 2 Medications 3 Medications Visual Outcome: Eyes without lOP elevation Better II Same~
Worse"" Eyes with lOP elevationtt Better Same Worse Complications: Phthisis bulbi Corneal decompensation Oil infiltrating anterior chamber Rubeosis iridis
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7-80 47.6 ± 21.3 37 (74%) 13 (26%) 35 (70%) 7 (14%) 2(4%) 2(4%) 2(4%) 1 (2%) 1 (2%) 6 (12%) 2(4%) 2(4%) 1 (2%) 1 (2%) 1-22 10.7 ± 5.1 9 (18%) 6(12%) 3(6%) 20 (40%) 50 (100%) 32 (64%) 21 (42%) 2-51 16.6 ± 12.1 0-45 16.7 ± 9.3 24 (48%) 32 (64%) 13 (26%) 14 (28%) 5 (10%) 16 (32%) 11 (22%) 4(8%) 1 (2%) 26 (52%) 10 (20%) 9(18%) 7 (14%) 24 (48%) 8 (16%) 8(16%) 8(16%) 7 (14%) 6 (12%) 6(12%) 3(6%)
Nguyen et al . Intravitreal Silicone Oil Injection
Table 2.
(continued)
SD = standard deviation; PVR = proliferative vitreoretinopathy; lOP • Before silicone oil removal or glaucoma surgery.
= intraocular pressure .
t Postoperative lOP at least 25 mmHg and elevated at least 10 mmHg above preoperative level. t Duration of glaucoma therapy was at least one to five weeks. § Duration of glaucoma therapy was the entire course of follow-up or until surgery was performed to lower the lOP.
II Postoperative visual acuity at least two lines better than preoperative visual acuity. ~
Postoperative visual acuity within one line of preoperative visual acuity .
•• Postoperative visual acuity at least two lines worse than preoperative visual acuity.
tt Visual acuities for those eyes that underwent surgery to lower the lOPs are final acuities after surgery was performed.
create a tract in the capsule through which a silicone tube was passed and secured to the buckling element. The capsule was closed with 8-0 polyglactin suture, and irrigation of the potential space inside the capsule was performed through the tube. The tube insertion, donor scleral graft, conjunctival closure, subconjunctival medications, and postoperative medications were similar to those with Molteno implantation. Nd:YAG transscleral cyclophotocoagulation was performed on one patient. A Shields lens was placed after the patient had received retrobulbar anesthesia, and a total of 36 spots were applied approximately 1.0 to 1.5 mm posterior to the limbus over 360 0 , sparing the 1 clock hour around both the 3-0'clock and 9-0'clock positions. The patient received a topical combination of fluorometholone and sulfacetamide sodium for several weeks after surgery.
Results Demographic, preoperative, intraoperative, and postoperative data are summarized in Table 2. The patients' ages ranged from 7 to 80 years (mean ± standard deviation, 47.6 ± 21.3 years). The mean overall follow-up for patients before their having undergone silicone oil removal or glaucoma surgery was 16.6 ± 12.1 months (range, 2 to 51 months), and the mean follow-up for those patients who underwent surgical procedures to lower their lOPs was 13.5 ± 11.0 months (range, 0.2 to 33 months). The follow-up periods for five patients were limited by their deaths from human immunodeficiency virus infection or other causes unrelated to their eye surgeries. All patients had complicated retinal detachments that were associated with the following conditions: 35 (70%) eyes with proliferative vitreoretinopathy, 7 (14%) eyes with cytomegalovirus retinitis, 2 (4%) eyes each with severe proliferative diabetic retinopathy, giant retinal tears, and colobomas, and 1 (2%) eye each with massive choroidal hemorrhage and recurrent retinal detachment. Thirtyseven eyes were aphakic, and 20 eyes had undergone previous pars plana vitrectomy with gas-fluid exchange or silicone oil injection in attempts to effect retinal reattach-
ment. Eighteen (36%) eyes had previously placed scleral buckles, and 14 (28%) eyes underwent scleral buckling at the time of silicone oil injection. Inferior peripheral iridectomies were performed at the time of oil injection in 21 (42%) eyes. Six (12%) eyes of 6 patients had a diagnosis of glaucoma antedating silicone oil injection (2 patients each had congenital glaucomas and open-angle glaucomas, and 1 patient each had neovascular and secondary angle-closure glaucomas); 3 other patients who had elevated lOPs without diagnoses of glaucoma also were using antiglaucoma medications preoperatively. Twenty-four (48%) eyes overall had postoperative lOPs of at least 25 mmHg and lOP increases of at least 10 mmHg above the preoperative levels. The preoperative lOPs ranged from 1 to 22 mmHg (mean ± standard deviation, 10.7 ± 5.1 mmHg), and the final lOPs before silicone oil removal or glaucoma surgery ranged from 0 to 45 mmHg (mean ± standard deviation, 16.7 ± 9.3 mmHg). Thirty-two (64%) eyes received antiglaucoma medications at least temporarily (from 1 to 5 weeks after surgery), and 16 of those eyes chronically received medications (for the duration offollow-up or until glaucoma surgery was performed) to control lOP. Silicone oil removal alone was performed on 14 eyes, and glaucoma surgery (with or without oil removal) was performed on 7 eyes with medically uncontrollable lOP. The outcomes of these eyes are presented in Table 3. Among the eyes that had silicone oil removal alone, lOP was controlled in eight eyes, and among the eyes that underwent a glaucoma procedure (with or without oil removal), lOP was controlled in four eyes. Of the nine eyes receiving antiglaucoma medications before silicone oil injection, one eye had no postoperative lOP elevation, two eyes had transient postoperative lOP elevations, three eyes received chronic antiglaucoma medical therapy, and three eyes underwent Molteno implantation (two of these eyes were categorized as qualified successes and one eye as a qualified failure). In our series overall, the postoperative visual acuities remained within 1 line of the preoperative visual acuities or improved in 35 (70%) eyes. Among the 24 eyes with lOP elevations (including the eyes on which glaucoma surgery was performed), the final postoperative visual
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Ophthalmology Volume 99, Number 10, October 1992 Table 3. Data Summary of Eyes Undergoing Surgery for Glaucoma (21 Eyes of 18 Patients) Surgical Procedures to Control lOP Silicone oil removal alone· Glaucoma procedurest Molteno implantation Modified Schocket procedure Nd:YAG laser cyclophotocoagulation Preoperative lOP (mmHg): Range Mean ± SD Postoperative lOP (mmHg): Range Mean ± SD Length of Follow-up (mos): Range Mean ± SD Surgical Outcome: Complete silicone oil removal alone Success Complete Qualified Failure Qualified Completer Molteno implantation Success Complete§ Qualified II Failure Qualified1T Complete·· Modified Schocket procedure Qualified failure tt Nd:YAG transscleral cyclophotocoagulation Complete success lOP
21 (42%) 14 (28%)
7 (14%)
5 (10%) 1 (2%)
1 (2%)
15-45
27.0 ± 7.3 4-31 15.8 ± 7.7 0.2-33
13.5 ± 11.0
14 (100%) 8 (57%)
7 (50%)
1 (7%) 6(43%) 0(0%) 6 (43%) 5 (100%) 3(60%) 1 (20%) 2 (40%) 2(40%)
1 (20%) 1 (20%) 1 (100%) 1 (100%) 1 (100%) 1 (100%)
= intraocular pressure; SD = standard deviation.
• All eyes had oil removed within three months of injection.
t One eye each that underwent Molteno implantation, modified Schocket procedure, and Nd:YAG transscleral cyclophotocoagulation also had silicone oil removed previously. t
Three eyes underwent glaucoma procedures, and three eyes lost light perception because of retinal redetachment associated with cytomegalovirus retinitis. § The eye underwent one-stage single-plate Molteno implantation.
II Both eyes underwent one-stage single-plate Molteno implantations. 11 The eye underwent two-stage single-plate Molteno implantation. The final lOP was 23 mmHg but considered adequately controlled in this eye. •• The eye underwent two consecutive two-stage single-plate Molteno implantations and lost light perception because of retinal necrosis associated with severe proliferative diabetic retinopathy.
tt The final lOP was 23 mmHg but considered adequately controlled in this eye.
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acuities remained the same or improved in 16 eyes. All patients who lost light perception did so primarily because of retinal redetachment, ischemia, or necrosis rather than uncontrolled lOP. The complications of silicone oil in this group of patients are summarized in Table 2. Seven (14%) eyes became phthisical. Six (12%) eyes developed corneal decompensation after undergoing silicone oil injection, and penetrating keratoplasty was subsequently performed on them. Oil infiltrated the anterior chambers of 6 (12%) eyes, none of which developed glaucoma. Three eyes (6%) developed postoperative rubeosis iridis, but not neovascular glaucoma. One eye that underwent two consecutive two-stage single-plate Molteno implantations developed a massive anterior chamber fibrin reaction that occluded one tube, which was subsequently cleared by intracameral tissue plasminogen activator. One patient who underwent one-stage single-plate Molteno implantation had oil in the tube tip that did not impair aqueous flow.
Discussion Although the anatomical and visual results obtained from intravitreal silicone oil injection used to manage complicated retinal detachments can be encouraging, late complications may preclude satisfactory long-term outcomes?,3 Although glaucoma is the second most common postoperative adverse occurrence after silicone oil injection (ranging from 15% to 22%),4-7 the mechanisms underlying its development remain controversial. deCorral and colleagues8 have shown that lOP elevation associated with silicone oil injection is independent of systemic conditions such as diabetes mellitus. In 1967, Watzke 2 described the occurrence of postoperative glaucoma after silicone oil injection and indicated that visible oil in the anterior chamber need not necessarily be present when the lOP is elevated. The mechanism for lOP elevation is indeed unclear, as Laroche and co-workers9 noted normal lOPs even when silicone globules were present in the angle. As Sugar and Okamura JO also pointed out, elevated lOP in the presence of silicone oil may be masked by ciliary body detachment from cyclitic membranes. Weinberg and colleagues!! reported elevated lOP after pars plana vitrectomy alone, attributing it to neovascularization, erythroclasis, hemorrhage, hemolysis, or phacolysis, Intraocular pressure elevation also may be due to peripheral anterior synechiae and/or inflammation. 8 In addition, we have seen that silicone oil may become emulsified and enter the anterior chamber (Fig 1), and postulate that it may sometimes impede the drainage of aqueous through the trabecular meshwork. Twenty-four (48%) eyes that underwent pars plana vitrectomy with silicone oil injection in our series had postoperative lOPs of at least 25 mmHg and lOP increases of at least 10 mmHg above the preoperative levels, occurring as early as the first postoperative day. Thirty-two
Nguyen et al . Intravitreal Silicone Oil Injection
Figure 1. Emulsified silicone oil in the anterior chamber after intravitreal injection for repair of a complicated retinal detachment.
(64%) eyes were receiving antiglaucoma medications for at least 1 to 5 weeks after surgery to control the lOPs; 16 of those eyes required chronic medications. Our incidence of glaucoma is higher than those previously reported; the reasons for this finding are unclear but may be related to our patients having had more complex pathology or our definition of glaucoma differing from those in other studies. In any case, given the relatively high incidences of glaucoma after intravitreal silicone oil injection noted in several studies, patients should be closely monitored for postoperative lOP spikes. IflOP elevation occurs, it should probably be treated aggressively to prevent further ischemia to the retina and optic nerve. As 8 of 9 (89%) eyes treated for elevated preoperative lOP had some amount of postoperative lOP elevation (3 of these eyes later underwent glaucoma surgery), our data suggest that patients with elevated lOPs before undergoing silicone oil injection may be particularly at risk for developing elevated postoperative lOP. In our series, 14 (28%) eyes with uncontrolled postoperative lOPs underwent complete silicone oil removal. Furthermore, seven patients (including three who previously had silicone oil removed) underwent glaucoma surgery to attempt lOP control. Because traditional filtering surgery is technically difficult because of conjunctival scarring from the retinal surgery and carries a poor prognosis in eyes having had multiple surgeries, artificial drainage devices or cyclodestructive procedures may be the most appropriate means to lower medically uncontrollable lOPs associated with intravitreal silicone oil. Three of the five eyes that underwent· Molteno implantation and the one eye that underwent Nd:YAG transscleral cyclophotocoagulation achieved lOP control; the one eye that underwent a modified Schocket procedure did not achieve a final lOP of 21 mmHg or less. However, relatively few patients underwent glaucoma procedures in our series, and additional studies are needed to determine which treatment modalities are most effective in
managing glaucoma in patients with intravitreal silicone oil. Among the 21 eyes in this series on which surgery was performed to manage elevated lOPs, all eyes either had scleral buckles and/or lacked intraoperative peripheral iridectomies (because the eyes were phakic or had inadequate amounts of iris present). Although the role of these factors in the development of glaucoma in our patients is uncertain, we re-emphasize the need for performing inferior peripheral iridectomies in aphakic and pseudophakic eyes undergoing intravitreal silicone oil injection, as Ando!2 has suggested, because they may prevent pupillary block by allowing silicone in the anterior chamber to return to the posterior chamber, and aqueous to flow from the posterior to the anterior chamber. In addition, a scleral buckle can impede outflow from the episcleral veins, thereby contributing to inadequate drainage of aqueous from Schlemm's canal, as well as inadequate venous drainage of the ciliary body, making it edematous and more likely to obstruct the angle. A variety of postoperative complications, including phthisis bulbi, occurred in this series, both in eyes that underwent glaucoma surgery and those that did not. Because these eyes frequently had complex pathology, the complications were often difficult to attribute to one etiology. Corneal edema, one of the most frequent adverse occurrences in our series, also has been reported to be the third most common complication in other series6 and is believed to be the result of corneal endothelial decompensation. All six of our patients who had corneal decompensation had oil in contact with the endothelium. Haut and co-workers! 3 reported that approximately 40% ofpatients who developed glaucoma associated with silicone oil injection had oil in the anterior chamber. In our series, 12% of eyes had silicone oil infiltrating the anterior chamber, but none of them developed glaucoma. Three eyes in our series developed rubeosis iridis, but none of them developed neovascular glaucoma, which is consistent with deCorral and colleagues' report. 8 Fourteen percent of the eyes in our series became phthisical; this rate is also somewhat consistent with a report by Weinberg et all! in which 1 of 5 eyes (20%) became phthisical after silicone oil injection. Glaucoma surgery itself was associated with relatively few complications and did not appear to contribute to ophthalmic morbidity overall. In summary, lOP elevation is a common occurrence after intravitreal silicone oil injection used in the management of complicated retinal detachments. The underlying mechanism is often unclear, and may frequently be multifactorial in nature. Patients should be monitored closely for the development of elevated postoperative lOP, especially if they have a history of elevated preoperative lOP, and they may benefit from aggressive medical and/ or surgical treatment of glaucoma with silicone oil removal, glaucoma implants, or cyclodestructive procedures to avoid additional optic nerve damage. Acknowledgment. The authors thank Thomas Chu, MD,
PhD, for providing the photograph.
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References 8. 1. Minckler OS, Heuer OK, Hasty B, et al. Clinical experience with the single-plate Molteno implant in complicated glaucomas. Ophthalmology 1988;95:1181-8. 2. Watzke RC. Silicone retinopiesis for retinal detachment. A long-term clinical evaluation. Arch Ophthalmol 1967;77: 185-96. 3. Kanski 11, Daniel R. Intravitreal silicone injection in retinal detachment. Br J Ophthalmol 1973;57:542-5. 4. Alexandridis E, Daniel H. Results of silicone oil injection into the vitreous. Dev Ophthalmol 1981 ;2:24-7. 5. Grey RHB, Leaver PK. Results of silicone oil injection in massive preretinal retraction. Trans Ophthalmol Soc UK 1977;97 :238-41. 6. Leaver PK, Grey RHB, Garner A. Complications following silicone-oil injection. Mod Probl Ophthalmol 1979;20: 290-4. 7. Ni C, Wang W-J, Albert OM, Schepens CL. Intravitreous
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silicone injection. Histologic findings in a human eye after 12 years. Arch Ophthalmol 1983;101:1399-1401. deCorral LR, Cohen SB, Peyman GA. Effect of in trav itreal silicone oil on intraocular pressure. Ophthalmic Surg 1987;18:446-9. Laroche L, Pavlakis C, Saraux H, Orcel L. Ocular findings following intravitreal silicone injection. Arch Ophthalmol 1983; 101 :1422-5. Sugar HS, Okamura 10. Ocular findings six years after intravitreal silicone injection. Arch Ophthalmol 1976;94: 612-5. Weinberg RS, Peyman GA, Huamonte FV. Elevation of intraocular pressure after pars plana vitrectomy. Albrecht Von Graefes Arch Klin Exp Ophthalmol 1976;200: 157 -61 . Ando F. Intraocular hypertension resulting from pupillary block by silicone oil [letter]. Am J Ophthalmol 1985;99: 87-8. Haut J, Ullern M, Chermet M, Van Effenterre G. Complications of intraocular injections of silicone combined with vitrectomy. Ophthalmologica 1980; 180:29-35.
