SILICONE OIL INJECTION INDUCED GLAUCOMA: INCIDENCE AND MANAGEMENT

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1 SILICONE OIL INJECTION INDUCED GLAUCOMA: INCIDENCE AND MANAGEMENT Ahmad Elsayed Hudieb Department of Ophthalmology Faculty of Medicine, Al- Azhar University ABSTRACT Purpose: Intravitreal silicone oil injection used for managing complicated retinal cases 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. Materials and Methods: The postoperative courses of 50 patients who underwent pars plana vitrectomy and silicone oil injection for the management of complicated vitreoretinal cases 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 30.7 ± 9.3 mmhg (range, 20.1 to 40.9 mmhg), with a mean follow-up of 14.6 ± 10.1 months (range, 2 to 24 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. Twenty one (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 subscleral trabeculectomy with mitomycin C "0.04%" and in 1 eye that underwent Nd:YAG transscleral cyclophoto-coagulation, but not in 1 eye that underwent Ahmed glaucoma valve implantation (mean follow-up, 10.5 ± 9.0 months; range, 1 to 20 months). Conclusion: Intraocular pressure elevation 133

Ahmad Elsayed Hudieb is a common occurrence after intravitreal silicone oil injection. The underlying mechanism may often be multifactorial in nature.

2 Ahmad Elsayed Hudieb 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. INTRODUCTION Intravitreal Silicone Oil Injection can be useful in the management of complicated vitreoretinal cases. Because silicone oil can internally tamponade the retina, it can effect anatomic reattachment even in the presence of proliferative vitreoretinopathy. However, intravitreal silicone 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. A known complication of silicone oil use has been the development of secondary glaucoma. Mechanisms of secondary glaucoma following the silicone oil tamponad Table (1) 1-silicone oil leading to pupillary block "closed angle". 2- migration of silicone oil into the anterior chamber with consequent mechanical impediment to filtration "open angle"(fig.1) 3- emulsified silicone oil causing mechanical impediment to aqueous out flow 4- pre-existing glaucoma (fig2). Table 1. Mechanism of Secondary Glaucoma from Silicone Oil 134

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.

3 Fig. 1. A bubble of Silicone oil in the Anterior chamber Fig. 2. inverted hypopyon, emulsified oil in the Anterior chamber 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. MATERIALS AND METHODS 50 patients underwent pars plana vitrectomy and silicone oil injection for the management of complicated retinal cases are retrospectively reviewed. All patient records were retrospectively reviewed for preoperative, intraoperative, and postoperative data. Elevated lop was defined before reviewing the charts as any postoperative lop of at least 25 mmhg that also was 135

4 Ahmad Elsayed Hudieb 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 2) 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. (Table I) Table 2. Categories of Glaucoma Surgical Outcome Complete Success : 6 mmhg ~ lop ~ 21 mmhg without medication. Qualified Success : 6 mmhg ~ lop ~ 21 mmhg with medication. Qualified Failure : lop> 21 mmhg. Complete Failure : Further glaucoma surgery (or recommendation thereof), hypotony, devastating complication, or loss of 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 subscleral trabeculectomy, Ahmed glaucoma valve implantation, and Nd : YAG transscleral cyclophotocoagulation. Conclusion of the procedures; postoperatively, patients were treated with topical I % prednisolone acetate for several months and topical antibiotics for I to 2 weeks. 136

5 RESULTS The patients ages ranged from 7 to 70 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 14.6 ± 10.1 months (range, 2 to 24 months), and the mean follow-up for those patients who underwent surgical procedures to lower their lops was 10.5 ± 9.0 months (range, 1 to 20 months). All patients had complicated retinal cases that were associated with the following conditions: 35 (70%) eyes with proliferative vitreoretinopathy, 7 (14%) eyes with advanced proliferative diabetic retinopathy "PDR", 2 (4%) eyes each with severe ocular trauma, giant retinal tears, and colobomas, and 1 (2%) eye each with massive choroidal hemorrhage and recurrent retinal detachment. Thirty seven 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 reattachment. 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. Twentyfour (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 137

6 Ahmad Elsayed Hudieb ranged from 20.1 to 40.9 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 subscleral trabeculectomy (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 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. 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. 138

7 Table 3. Data Summary of Eyes Undergoing Surgery for Glaucoma (21 Eyes of 21 Patients) Surgical Procedures to Control lop Silicone oil removal alone Glaucoma procedures 1- Subscleral trabeculectomy 2- Ahmed glaucoma valve 3- 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 Subscleral trabeculectomy Success Complete Qualified II Failure Qualified1T Complete : Ahmed glaucoma valve Qualified failure tt Nd:YAG transscleral cyclophotocoagulation Complete success lop = intraocular pressure; SD = standard deviation. 21 (42%) 14 (28%) 7 (28%) 5 (10%) 1 (2%) 1(2%) (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%) 139

8 Ahmad Elsayed Hudieb DISCUSSION Although the anatomical and visual results obtained from intravitreal silicone oil injection used to manage complicated retinal cases 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 (Fig 3). decorral and colleagues "8" have shown that lop elevation associated with silicone oil injection is independent of systemic conditions such as diabetes mellitus. In 1999, Watzke2 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-workers "9" noted normal lops even when silicone globules were present in the angle. As Sugar and OkamuraJO 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, and postulate that it may sometimes impede the drainage of aqueous through the trabecular meshwork. 140

9 Fig. 1 Mechanisms of secondary glaucoma following the silicone oil tamponade. a. Silicone oil leading to pupillary block (closed angle). b Mechanical obstruction due to silicone oil filling the total anterior chamber (open angle), with associated keratopathy superiorly. c Emulsified silicone oil in anterior chamber. d Emulsified silicone oil causing mechanical impediment to aqueous outflow. Twenty-four (48%) eyes that underwent pars plana vitrectomy with silicone oil injection in our series had post-operative 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 (64%) eyes were receiving antiglaucoma medications for at least 1 to 5 weeks after surgery to control the IOPs; 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. If lop 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 141

10 Ahmad Elsayed Hudieb 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 subscleral trabeculectomy and the one eye that underwent Nd:Y AG trans-scleral cyclophotocoagulation achieved lop control; the one eye that underwent an Ahmed glaucoma valve implantation 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 ir-idectomies (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 pseudo-phakic 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 142

11 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. Be-cause 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 series "6" 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 coworkers"3" reported that approximately 40% of patients 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 some what 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 cases. 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 143

12 Ahmad Elsayed Hudieb glaucoma with silicone oil removal, glaucoma implants, or cyclodestructive procedures to avoid additional optic nerve damage. 144

13 REFERENCES 1. Minckler OS, Heuer OK, Hasty B, et al. Clinical experience with the single-plate Molteno implant in complicated glau-comas. Ophthalmology 2008 ;95: Watzke RC. Silicone retinopiesis for retinal detachment. A long-term clinical evaluation. Arch Ophthalmol 1967;77: Kanski 11, Daniel R. Intravitreal silicone injection in retinal detachment. Br J Ophthalmol 2003 ;57: Alexandridis E, Daniel H. Results of silicone oil injection into the vitreous. Dev Ophthalmol 1999 ;2: Grey RHB, Leaver PK. Results of silicone oil injection in massive preretinal retraction. Trans Ophthalmol Soc UK 1997 ;97 : Leaver PK, Grey RHB, Garner A. Complications following silicone-oil injection. Mod Probl Ophthalmol 1999 ;20: Ni C, Wang W-J, Albert OM, Schepens CL. Intravitreous 1526 silicone injection. Histologic findings in a human eye after 12 years. Arch Ophthalmol ;101: decorral LR, Cohen SB, Peyman GA. Effect of in trav it real silicone oil on intraocular pressure. Ophthalmic Surg 1987;18: Laroche L, Pavlakis C, Saraux H, Orcel L. Ocular findings following intravitreal silicone injection. Arch Ophthalmol 2007 ; 101: Sugar HS, Okamura 10. Ocular findings six years after in- travitreal silicone injection. Arch Ophthalmol 2006 ; 94: Weinberg RS, Peyman GA, Huamonte FV. Elevation of intraocular pressure after pars plana vitrectomy. Albrecht Von Graefes Arch Klin Exp Ophthalmol 2004 ;200: Ando F. Intraocular hypertension resulting from pupillary block by silicone oil [letter]. Am J Ophthalmol 1995 ;99: Haut J, Ullern M, Chermet M, Van Effenterre G. Compli- cations of intraocular injections of silicone combined with vitrectomy. Ophthalmologica 1990 ; 180:

Anatomical results and complications after silicone oil removal

Romanian Journal of Ophthalmology, Volume 61, Issue 4, October-December 2017. pp:261-266 GENERAL ARTICLE Anatomical results and complications after silicone oil removal Brănişteanu Daniel Constantin* **,