Anterior Chamber Dislocation of Dexamethasone Implant in the Presence of Carlevale Sutureless Scleral Fixation Intraocular Lens

Abstract

Dexamethasone intravitreal implant (Ozurdex^®; Allergan, Inc., CA, USA) has been proved to be effective in a variety of clinical settings including cases of pseudophakic cystoid macular edema. Uncommonly, this implant can migrate from the vitreous cavity and into the anterior chamber, especially in vitrectomized eyes with lens capsule defects. We report herein a rare case of anterior chamber migration and illustrate the passageway of the dexamethasone intravitreal implant through a new type of scleral fixated lens, the Carlevale IOL (Soleko-Italy). A 78-year-old woman was left aphakic following a complicated right eye hypermature cataract surgery with posterior capsule rupture and zonular dehiscence. Shortly thereafter, she underwent a planned combined pars plana vitrectomy with the placement of a Carlevale sutureless scleral fixated intraocular lens for the treatment of her aphakia. Due to a subsequent persistent cystoid macular edema that was unresponsive to topical treatment and sub-tenon corticosteroids, an intravitreal dexamethasone implant was injected. Eleven days after implantation, the patient presented with a floating implant in the anterior chamber and corneal edema. Following an immediate surgical removal, corneal edema resolved and visual acuity improved. One year later, results remain stable without macular edema recurrence. Anterior chamber migration of the Ozurdex implant is a potential complication in vitrectomized eyes, even when new types which are larger and specially designed for scleral fixation intraocular lenses are utilized. Corneal complications can be reversible following an immediate removal of the implant.

Introduction

Dexamethasone intravitreal implant (Ozurdex^®; Allergan, Inc., CA, USA) has been approved for the treatment of macular edema due to branch or central retinal vein occlusion, diabetic macular edema, and noninfectious uveitis affecting the posterior segment. It has also been reported to be effective in cases with pseudophakic cystoid macular edema (CME) [1–3]. Ozurdex is a biodegradable implant containing 0.7 mg of preservative-free dexamethasone released slowly over a period of up to 6 months. This 6 mm-length and 0.46 mm-diameter stick-shaped implant is inserted into the vitreous cavity using a 22-gauge needle.

Ozurdex insertion is knowingly related with short-term ocular complications such as endophthalmitis and retinal detachment as well as long-term adverse effects like cataract and secondary glaucoma [1, 3]. In addition to the risk of desegmentation of the implant [4], an unusual side effect is implant migration into the anterior chamber, causing vision-threatening complications that may involve corneal decompensation [2, 3]. We report herein a case of anterior migration of an Ozurdex implant in a patient with a new type of suture-free scleral fixated intraocular lens, the FIL-SSF Carlevale (Soleko-Italy).

Case Report

A 78-year-old woman, with a white hypermature cataract in her right eye, underwent a complicated cataract surgery with posterior capsule rupture and zonular dehiscence and was left aphakic. Three days later, she underwent a planned combined pars plana vitrectomy with a sutureless scleral fixated Carlevale lens for the treatment of her aphakia. The Carlevale lens was fixated to the sclera at 3 and 9 o’clock positions through equidistant sclerotomies at 1.5 mm from the limbus. The T-shaped harpoons were placed and secured under scleral flaps created with a 300-μm thickness accurate depth knife (BD Beaver, Visitec International). Despite an initially good result with a best-corrected visual acuity (BCVA) of 20/25 (Snellen), the patient developed CME with reduction of BCVA to 20/40 at 2 months post-op. Spectral domain optical coherence tomography confirmed the presence of CME with a foveal thickness of 500 μm in the right eye (Fig. 1a). Following a 2-month course of topical treatment with nepafenac 3 mg/mL (Nevanac) once daily and dexamethasone 0.1% (Maxidex) as well as a posterior sub-tenon injection of triamcinolone acetonide (40 mg/mL) (STTA), there was still a persistent CME (Fig. 1b) with foveal thickness of 371 μm. Since there was no response to treatment, and prior thorough patient counseling, an off-label Ozurdex implant injection was performed via the pars plana at 3.5 mm from the limbus. Eleven days after implantation, the patient complained of blurry vision, and subsequent slit-lamp biomicroscopy revealed migration of the Ozurdex in the anterior chamber (Fig. 2a) with corneal edema and Descemet’s membrane folds (Fig. 2b). The implant was removed the same day on an urgent basis, in order to decrease the risk of permanent endothelial decompensation. Following surgical removal, both corneal edema and visual acuity gradually improved. At 1 month of follow-up, the cornea was clear, with no observed anterior chamber inflammation and BCVA of 20/25 (Fig. 2c). Of note, a reduction of CMO was also surprisingly noticed which eventually completely resolved and remained quiescent at 1-year follow-up (Fig. 1c).

Fig. 1.

SD-OCT images showing the presence and progress of CME following vitrectomy and insertion of Carlevale scleral fixated IOL at 2 months post-op, with a foveal thickness of 500 μm (a) after 2 months of topical treatment and sub-tenon injection of triamcinolone, persistent edema with foveal thickness of 371 μm (b), and at 3 months following urgent removal of the migrated implant in the AC, complete resolution of the edema (c).

Fig. 2.

Anterior segment images of the dislocated dexamethasone implant (a), corneal edema and Descemet’s folds (b), and complete resolution of the edema at 1 month post implant removal (c).

Discussion

The migration of the dexamethasone implant in the anterior chamber of vitrectomized eyes, although unusual (4.8% [5]), has been well described as a complication in clinical settings such as aphakia, complicated cataract surgery with lack of posterior capsule integrity, zonular dehiscence, and posterior pars plana vitrectomy [2, 3]. There is still inconclusive evidence regarding risk factors for anterior segment migration, such as lying in a prone position and long plane journeys within the first week after dexamethasone implantation [3]. This is, to the best of our knowledge, the first description of Ozurdex migration in the AC in the presence of Carlevale intraocular lens.

Carlevale IOL is specifically designed for sutureless intrascleral fixation in the absence of capsular support. The overall length is 13.2 mm with an optic diameter of 6.5 mm and a 10 angulation. Each haptic consists of a T-shaped anchor plug linked to the optical plate by a flexible connection mesh. Based on the manufacturer’s guidelines, it is inserted through a scleral tunnel at 1.5 mm from the limbus. Main advantages include the low degree of IOL tilt and the possibility of achieving good centration due to IOL design. Mularoni et al. [6] reported that the mean distance of the IOL optic plate from the iris plane was less than 0.86+/−0.27 μm.

In our case, we used pre-implant removal measurements made on images acquired with anterior segment spectral domain optical coherence tomography, in order to illustrate a potential passageway of the Ozurdex implant to the AS. According to these measurements, the distance between the iris plane and the Carlevale lens optic plate was 0.94–0.95 mm, therefore, slightly increased compared to the values reported in the literature (Fig. 3) [6]. This discrepancy can be attributable to an inadvertent more posterior fixation of the Carlevale lens via a scleral tunnel toward 2 mm from the limbus instead of the 1.5 mm that we initially aimed for. The thickness of the Ozurdex implant that has a diameter of 0.46 mm, almost half of the space observed between the pupil and the IOL optic plate, provides a partial explanation of a pathway of migration into the AC through an otherwise stable scleral fixated lens.

Fig. 3.

Anterior segment OCT images with measurements between the anterior surface of the Carlevale optic plate and the pupillary margin, showing increased space compared to the literature. OCT, optical coherence tomography.

Based on the case presented herein, we support that in order for an implant to migrate in the AS through a Carlevale IOL, more conditions need to be met. First, the lack of vitreous support in vitrectomized eyes as in our case – and in several cases of other scleral fixated IOLs – results in an increased free movement of the implant in the vitreous cavity, implying a possible switch of orientation during changes of head posturing. Second, because of the particular design of the lens, it is unlikely that the 6 mm-length implant can migrate through the flexible mesh connecting the optic to the T-shaped harpoon. On the contrary, migration of the implant is more likely through the remaining part of the optic plate which is opposite to the anchoring sites. In our case, the Carlevale lens was fixated at 3 and 9 o’clock positions; therefore, we speculate that the implant initially found its way to the AC through either the superior or inferior clock hours and subsequently through the slightly increased space between the pupil and the optic plate. Prolonged prone head posturing might have played a role in the anterior movement of the implant; nevertheless, we were not able to confirm such posturing with the patient. Lastly, we need to acknowledge that a minor measurement error in terms of distance from limbus or centration, even if not clinically significant or detectable, might on the contrary create the necessary space for the implant to migrate in vitrectomized eyes.

Notably, dislocation of an intravitreal Ozurdex implant into the anterior chamber can result in corneal edema due to mechanical trauma or chemical toxicity on the corneal endothelium [2]. A prompt removal of the implant has been reported to successfully reduce the risk of irreversible endothelial damage, provided that time from migration to recognition is less than 3 weeks [2]. In this case, an emergency removal of the implant was performed in order to avoid permanent damage to the corneal endothelium. Four weeks postoperatively, corneal edema resolved and BCVA significantly improved to 20/25; hence, our case offers further confirmation that corneal edema probably occurred from mechanical trauma due to the increased rigidity of the implant. Interestingly, the macula remained flat with no CMO recurrence at 1-year follow-up despite the short-time stay of the implant in the vitreous cavity.

Conclusion

In conclusion, migration of dexamethasone implant in the anterior chamber can be observed even in the presence of the specifically designed scleral fixation intraocular lens Carlevale. This case highlights that the IOLs’ large optic plate and the elaborated mesh of the haptics may not prevent the anterior movement of the implant and underlines the necessity of very close follow-up of this off-label use of Ozurdex in order to timely diagnose the aforementioned complication in vitrectomized eyes. Cautious fixation of the posterior chamber IOL at 1.5 mm might prove to be protective from migration, and prompt removal of the implant is necessary to prevent permanent corneal damage. In scenarios of the complete absence of capsular support, thorough patient counseling is advised before implant insertion. The CARE Checklist has been completed by the authors for this case report, attached as online supplementary material (for all online suppl. material, see https://doi.org/10.1159/000529790).

Statement of Ethics

Ethical approval is not required for this study in accordance with local or national guidelines. Written informed consent was obtained from the patient for publication of the details of their medical case and any accompanying images.

Conflict of Interest Statement

The authors have no financial disclosures (P.S., P.G., S.T., E.C., E.M., and E.K.).

Funding Sources

No funding or grant support was received. All the authors attest that they meet the current ICMJE criteria for authorship.

Author Contributions

Panagiotis Stavrakas: conceptualization, methodology, writing – review and editing, and supervision; Panos Gartaganis and Evangelia Chalkiadaki: data curation and software; Styliani Totou: writing – original draft; Evangelos Manousakis: investigation; Efthymios Karmiris: conceptualization, methodology, and supervision.

Funding Statement

No funding or grant support was received. All the authors attest that they meet the current ICMJE criteria for authorship.

Data Availability Statement

All data generated or analyzed during this study are included in this article. Further inquiries can be directed to the corresponding author.