The dexamethasone intravitreal implant (Ozurdex; Allergan, Irvine, CA) has demonstrated efficacy in the treatment of macular edema associated with retinal vein occlusion and noninfectious uveitis affecting the posterior segment in prospective clinical trials.1–3 Corneal edema may be observed with implant migration into the anterior chamber in aphakic patients or pseudophakic patients with a disrupted posterior capsule, particularly in patients who have undergone prior vitrectomy.4–6 We describe a novel approach for the removal of the dexamethasone intravitreal implant abutting the corneal endothelium, which uses standard vitreoretinal instrumentation, viscoelastic, a modified Sheets glide, and angled forceps in order to avoid posterior migration of the implant during surgery and to minimize iatrogenic morbidity.
A 59-year-old woman with a history of retinal detachments in both eyes repaired with scleral buckle and bilateral vitrectomy demonstrated recalcitrant cystoid macular edema (CME) in the right eye, which had been treated with repeated intravitreal corticosteroid injections. Slit lamp examination showed a large inferior peripheral iridectomy owing to a history of silicone oil instillation and a posterior chamber intraocular lens (PC-IOL) with an open posterior capsule in the right eye. Funduscopic examination revealed advanced glaucomatous cupping in both eyes. Because of recurrent CME, a dexamethasone intravitreal implant was administered, and the patient complained of decreased vision in the right eye. She was promptly referred to our institution for an evaluation.
Her visual acuity was 20/200 in the right eye, and her intraocular pressure was 26 mm Hg despite maximum tolerated medical therapy for steroid-induced glaucoma. Formal static perimetry with a Humphrey visual field 24-2 algorithm revealed a dense superior arcuate and early inferior arcuate defect. Slit lamp examination showed diffuse corneal edema with corneal endothelial folds, and the dexamethasone implant was located in the inferior anterior chamber angle abutting the corneal endothelium (Figure 1). Because of the acute decrease in vision and the position of the dexamethasone implant, explantation of the anteriorly located dexamethasone implant was elected.
Intravitreal dexamethasone implant found in the inferior angle. Note the associated corneal edema worse adjacent to the implant.
A standard 20-gauge pars plana vitrectomy setup was established to maintain infusion pressure. A modified Sheets glide was cut to approximately 3 mm in width to cover the peripheral iridectomy and pupil. A 2.8 keratome was used to create a biplaned superonasal clear corneal incision. Viscoelastic was injected over an inferior peripheral iridectomy site to prevent posterior migration of the Ozurdex implant during the surgery. A Sinskey hook was used to free the implant from the anterior chamber angle and orient it parallel to the Sheets glide. Angled McPherson forceps were used to grasp the implant parallel to its long axis and avoid dissolution of the implant into multiple particulate fragments (Figure 2). Following successful explantation of the dexamethasone implant, the viscoelastic was removed, and the corneal wound was closed with a 10-0 nylon suture.
McPherson forceps are used to grasp the brittle dexamethasone implant parallel to the long axis.
Postoperatively, the patient experienced improvement in the corneal edema; however, persistent corneal edema prompted Descemet’s stripping endothelial keratoplasty with an improvement in her best corrected visual acuity to 20/60 at final 12-month follow-up (Figure 3).
Postoperative photograph after removal of intravitreal dexamethasone implant. Note resolution of corneal edema. Intraocular pressure had returned to physiologic levels.
While migration of the dexamethasone implant into the anterior chamber has been infrequently reported,4–6 endothelial damage and corneal edema may develop and require corneal transplantation.4 In the largest series of dexamethasone implant anterior chamber migration involving 18 cases, there were 16 cases (89%) of corneal edema. More concerning, in 10 patients (71%), the corneal edema did not resolve despite implant removal, and keratoplasty was recommended in six patients (43%).4 The package insert for the dexamethasone implant was modified in September 2012 in order to reflect that contraindications for the dexamethasone implant include aphakia and an anterior chamber intraocular lens with rupture of the posterior capsule. Khurana et al reported anterior chamber migration in patients with a posterior chamber intraocular lens; four of six patients did not have a lens capsule, which the authors speculate may have contributed to anterior chamber migration. It is also notable that all 15 patients in their series had a history of prior vitrectomy as well, which may be another risk factor for implant migration.4
While patients without corneal edema may be observed or managed medically with supine positioning and pupillary dilation to allow the implant to migrate posteriorly, the majority of patients reported in case reports and case series have required intervention.4–6 YAG laser fragmentation is a consideration if the implant is lodged between the intraocular lens and iris; however, implant removal with vitreoretinal instrumentation may be required. It is notable that earlier implant removal appears to reduce the likelihood of permanent corneal edema and prompt removal should be considered in patients presenting with corneal edema.4
Removal of the implant using aspiration with the vitreous cutter has been reported; however, the implant tends to disintegrate into multiple fragments, making complete removal of the implant difficult. Forceps removal has also been discussed, but the friability of the implant makes removal of the implant more time-consuming if the implant is grasped perpendicular to its long axis. We hypothesize that the implant migrated via the large inferior peripheral iridectomy in our patient and lodged into the inferior chamber angle with subsequent corneal edema. Intraoperatively, viscoelastic and the modified Sheets glide were used to avoid posterior migration of the implant through the pupil and inferior peripheral iridectomy. In addition, our technique of grasping the implant along its long axis avoided fragmentation of the implant. The implant has been described to disintegrate into numerous fragments with minimal manipulation, and posterior migration of these fragments during removal requires a posterior approach involving a vitreous cutter to eliminate them.4
In summary, we describe a practical technique for successful explantation of the dexamethasone implant (video available at www.Healio.com/OSLIRetina). Besides the contraindications of aphakic lens status and AC-IOL with a disrupted posterior capsule, patients with a PC-IOL and a ruptured capsule, prior vitrectomy, and in our patient a large peripheral iridectomy, may be susceptible to this finding.
- Haller JA, Bandello F, Belfort R Jr, et al. Ozurdex Geneva Study Group. Randomized, sham-controlled trial of dexamethasone intravitreal implant in patients with macular edema due to retinal vein occlusion. Ophthalmology. 2010;117:1134–1136. doi:10.1016/j.ophtha.2010.03.032 [CrossRef]
- Haller JA, Bandello F, Belfort R Jr, et al. Dexamethasone intravitreal implant in patients with macular edema related to branch or central retinal vein occlusion twelve-month study results. Ophthalmology. 2011;118:2453–2460. doi:10.1016/j.ophtha.2011.05.014 [CrossRef]
- Lowder C, Belfort R Jr, Lightman S, et al. Dexamethasone intravitreal implant for noninfectious intermediate or posterior uveitis. Arch Ophthalmol. 2011;129:545–543. doi:10.1001/archophthalmol.2010.339 [CrossRef]
- Khurana RN, Appa SN, McCannel CA, et al. Dexamethasone implant anterior chamber migration: risk factors, complications, and management strategies. Ophthalmology. 2014;121:67–71. doi:10.1016/j.ophtha.2013.06.033 [CrossRef]
- Bansal R, Bansal P, Kulkarni P, et al. Wandering Ozurdex(®) implant. J Ophthalmic Inflamm Infect. 2012;2:1–5. doi:10.1007/s12348-011-0042-x [CrossRef]
- Vela JI, Crespi J, Andreu D. Repositioning of dexamethasone intravitreal implant (Ozurdex) migrated into the anterior chamber. Int Ophthalmol. 2012;32:583–584. doi:10.1007/s10792-012-9604-7 [CrossRef]