The nomadic Ozurdex®: Anterior migration of the dexamethasone implant and back!

Dexamethasone intravitreal implantation has been used in various retinal and uveal pathologies. Common complications include cataract formation and raised intraocular pressure. Although uncommon, migration of the implant has also been well reported. We describe a case with migration of the implant into the anterior chamber in a patient with a scleral-fixated intraocular lens, which was managed noninvasively by pupillary dilatation and positioning of the patient.

Introduction

The use of dexamethasone intravitreal implantation (Ozurdex®, Allergan Inc., Irvine, CA, USA) is becoming increasingly popular in the management of chronic retinal and uveal pathologies.[1] Although the advantages of this treatment are a longer duration of action and lower cost, it is not without complications, which include posterior subcapsular cataract formation, increased intraocular pressure (IOP), and glaucoma.[2] Migration of the implant into the anterior chamber is another known complication in aphakic eyes and pseudophakic eyes, with iris claw lenses and scleral-fixated intraocular lenses (SFIOLs).[345] Most of these cases have been managed surgically by removal or repositioning of the implant.[6] Although positioning of patients has successfully restored the implant in eyes with an anterior chamber intraocular lens, there have been no such reports in eyes with SFIOLs.[789]

Case Report

A 60-year-old man underwent vitrectomy and an SFIOL implantation for a traumatic subluxated intraocular lens with retinal detachment in the left eye. Subsequently, he developed cystoid macular edema (CME), for which he was treated with multiple intravitreal injections of bevacizumab and triamcinolone acetonide [Figure 1]. Since the response to these drugs was inadequate, he was advised an intravitreal dexamethasone implantation which he underwent after an informed consent.

Figure 1

Cystoid macular edema on spectral domain-optical coherence tomography prior to dexamethasone implant

A month after the implantation, he presented with sudden painless blurring of vision in his left eye of 3 days duration. He also complained of a linear floater. His corrected distance visual acuity (CDVA) had decreased from 20/200 prior to the implantation to 20/2000. Slit-lamp examination revealed corneal edema with Descemet's folds. The dexamethasone implant was seen inferiorly in the anterior chamber, mimicking a hypopyon [Figure 2]. Anterior segment spectral domain optical coherence tomography (SD-OCT; Avanti, Optovue, CA, USA) scan clearly demonstrated the Descemet's folds and implant in the anterior chamber [Figure 3]. The patient's pupil was pharmacologically dilated and he was advised supine positioning with slight chin elevation to allow the implant to re-enter the posterior segment. When reviewed the next day, the implant had migrated back to the vitreous cavity [Figures 4 and 5]. He was advised to avoid the prone position and to come for regular follow-up.

Figure 2

Corneal edema with dexamethasone implant was seen inferiorly in the anterior chamber, simulating a hypopyon (white arrow)

Figure 3

Anterior segment spectral domain-optical coherence tomography scan demonstrating Descemet's folds and the dexamethasone implant in the anterior chamber (white arrows)

Figure 4

Mild corneal edema and absence of the implant in the anterior chamber on the first follow-up day

Figure 5

Anterior segment spectral domain-optical coherence tomography scan demonstrating the re-migration of the dexamethasone implant int o the posterior segment

A week later, the CDVA had improved to 20/200 and the corneal edema had decreased. Despite the patient not being on miotics prophylactically, the implant did not migrate again into the anterior chamber. Two months postinjection, the CDVA was 20/120 and there was no recurrence of macular edema on the SD-OCT (Spectralis, Heidelberg, Germany) [Figure 6].

Figure 6

Resolution of cystoid macular edema on spectral domain-optical coherence tomography at 2-month follow-up

Discussion

Ozurdex® (Allergan Inc., Irvine, CA, USA) is a biodegradable intravitreal implant containing dexamethasone 700 μg. It has been used in the treatment of macular edema secondary to central and branch retinal vein occlusions, diabetic macular edema, and for the treatment of noninfectious posterior uveitis. It has also been shown to be effective in refractory pseudophakic CME.[12]

Although the absence of the lens capsule and prior vitrectomy are the risk factors for migration of the implant into the anterior chamber, it is also reported in cases with an intact posterior capsule.[810] The major complications of anterior chamber migration are corneal edema and elevation of IOP. Corneal endothelial toxicity is possibly due to mechanical trauma from the rigid implant as well as chemical toxicity. Corneal edema is noted when migration of the implant occurs in the early postoperative period and decreases in incidence when it occurs later due to the decreased rigidity of the implant. Unresolved or chronic corneal edema may be severe enough to warrant keratoplasty, thereby justifying an early surgical removal of the implant if it cannot be restored to the vitreous cavity by posturing the patients appropriately. The surgical management strategies include the use of forceps to remove the implant, yttrium-aluminum-garnet laser to fragment the implant, aspiration of the disintegrated implant, and repositioning of the implant into the posterior segment with a 30-gauge needle.[8] There are also reports of the implant being sutured to the sclera using a 10–0 nonabsorbable polypropylene suture to prevent the risk of anterior migration.[11] A no-touch technique for removal of the implant using viscoelastic has also been described.[12]

Although noninvasive repositioning of the implant by posturing has been reported, we describe it in a patient with SFIOL, which helped avoid surgical intervention and allowed the therapeutic effect of the implant to be maintained for 3 months. To prevent the recurrence of migration, use of miotics and avoiding the prone position may help.

Hence, it is important to be cautious while using a dexamethasone implant in patients with aphakia, pseudophakia including SFIOLs, and posterior capsular compromise or zonular dehiscence. With a regular follow-up, early detection of migration can be managed noninvasively, thereby preventing complications such as corneal decompensation and raised IOP.

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Conflicts of interest

There are no conflicts of interest.