Persistent Macular Choroidal Folds without Hypotony Following XEN Gel Stent Implantation: A Case Report

Article information

Dear Editor,

The XEN gel stent (Allergan), fabricated of hydrophilic porcine gelatin, forms a channel between the anterior chamber and the subconjunctival space for effective control of intraocular pressure (IOP). A previous study reported a rare instance of hypotony following XEN gel stent implantation, most such cases being temporary and not requiring surgical intervention [1].

We herein present a case of persistent macular choroidal folds without hypotony after XEN gel stent implantation. Written informed consent for publication of the research details and clinical images was obtained from the patient.

A 76-year-old female patient was referred due to uncontrolled IOP in the left eye. The patient had been undergoing treatment with topical dorzolamide hydrochloride, timolol maleate, brimonidine tartrate, and bimatoprost for pseudoexfoliative glaucoma. She had no trauma or medical history aside from hypertension. The IOP was 38 mmHg, with estimated central corneal thickness of 540 μm, and best-corrected visual acuity (BCVA) was 20 / 60. She had undergone cataract surgery and her estimated axial length was 23.12 mm. Bimatoprost was switched to latanoprost, but the IOP remained the same. For effective IOP control, XEN gel stent implantation was scheduled.

A conjunctival peritomy at the limbus was performed, followed by soaking in subtenon injection of 0.04% mitomycin C (MMC) for 3 minutes. Then, the XEN gel stent was implanted in the anterior chamber by an ab externo approach using a 27-gauge injector.

The day after surgery, the IOP was 10 mmHg with diffuse superior and nasal bleb. One month after surgery, although the IOP was 12 mmHg, macular choroidal folds were observed. Therefore, treatment with topical homatropine and prednisolone acetate was started. Three months after surgery, despite ongoing treatment with eye-drops and maintenance of IOP at 8 to 9 mmHg, the macular choroidal folds persisted while the BCVA worsened to 20 / 100. Due to the decline in BCVA and the patient’s subjective discomfort associated with the nasal bleb, along with the macular choroidal folds (Fig. 1A–1C), a compression suturing of the bleb near 10 o’clock position using 9-0 nylon was performed. Afterwards, the BCVA improved to 20 / 30, the IOP stabilized at 11 to 13 mmHg, and the macular choroidal folds improved (Fig. 1D–1F).

Fig. 1

Multimodal images of the patient. (A) Slit-lamp photography of nasal bleb 3 months after XEN gel stent (Allergan) implantation. (B) Widefield fundus photography of peripheral choroidal detachment 3 months after XEN gel stent implantation. (C) Spectral-domain optical coherence tomography image of macular choroidal folds 3 months after XEN gel stent implantation. (D) Slit-lamp photography of resolved nasal bleb after conjunctival compression suturing at the 10 o’clock position. (E) Widefield fundus photo of resolved peripheral choroidal detachment. (F) Spectral-domain optical coherence tomography image of resolved macular choroidal folds.

A previous study reported that after XEN gel stent implantation, transient postoperative hypotony with IOP less than 6 mmHg occurred in 26 eyes (27.1%), and that at 3-month follow-up, all eyes had an IOP of 6 mmHg or higher [1]. In the present case, the IOP remained within the normal range after XEN gel stent implantation; therefore, the development of chronic macular choroidal folds, which proved unresponsive to treatment with homatropine and prednisolone acetate, was our particular concern. Siegfried et al. [2] pointed out that hypotonic maculopathy can occur at any IOP that induces structural and functional changes in the eye. In this light, it is important to consider the possibility of post–XEN-gel-stent-implantation chronic macular choroidal fold development, even for cases where IOP is normal.

Siegfried et al. [2] reported that subconjunctival MMC can have direct toxic effects on the ciliary body, reducing aqueous production and leading to hypotony maculopathy thereby. In the current case, the use of 0.04% MMC might have caused the macular choroidal folds. Therefore, physicians should exercise caution in considering intraoperative antimetabolites for treatment of postoperative glaucoma patients having hypotony maculopathy risk factors such as myopia or young or old age [3].

A notable feature of the present case is the iatrogenic nasal bleb that developed after surgery, causing discomfort for the patient. According to Wanichwecharungruang and Ratprasatporn [4], the use of MMC during surgery has been reported to incur the development of nasal blebs. Another previous report indicated that in cases of uveitic glaucoma, hypotony following XEN gel stent implantation was resolved through conjunctival compression suturing [5]. The current case is unique in that the postoperative chronic macular choroidal folds were present without any numerical hypotony in a pseudoexfoliative glaucoma patient who had shown no evidence of uveitis or long-term intraocular inflammation. The patient’s discomfort due to the nasal bleb, along with the macular choroidal folds, were successfully managed with bleb compression suturing.

In conclusion, we should be aware that after XEN gel stent implantation, chronic macular choroidal folds can occur in the absence of any numerical hypotony. Macular choroidal folds can be effectively resolved through bleb compression suturing.

Article information Continued