Glaucoma drainage device implantation in a pregnant woman with axenfeld–rieger syndrome

Abstract

Axenfeld–Rieger syndrome (ARS) is a rare disease characterized by anterior segment anomalies with or without glaucoma. A 28-year-old antenatal female diagnosed with ARS presented with uncontrolled intraocular pressures (IOPs) and advanced glaucoma despite maximal medical therapy and progressive vision loss during her third trimester. The refractory and progressive nature of the disease, with useful vision in one eye, necessitated immediate surgical intervention, following which there was successful control of IOP, lasting till the final follow-up at 18 months. We discuss the role of glaucoma surgery, for an ARS patient with refractory glaucoma during the third trimester with a comprehensive review of literature.

Introduction

Glaucoma is reported to complicate approximately 50% of Axenfeld–Rieger syndrome (ARS) cases and is the main cause of vision loss. The elevated intraocular pressure (IOP) in ARS is due to inherent iridogoniodysgenesis and iris strands that bridges the angle structures.[1] In the case presented, glaucoma, which was medically well controlled in the prenatal period, had worsened antenatally, necessitating an emergency surgical management to preserve vision.

Case Report

A 28-year-old female patient with an obstetric score of G2P1A0 L1 presented in her third trimester with complaints of progressive visual loss for 6 months. She was a known case of ARS with secondary glaucoma in both eyes (OU); diagnosed in 2018 [Figure 1f]. She was taking dorzolamide hydrochloride 2%, timolol maleate 0.5%, and bimatoprost 0.02% to achieve control of IOPs. The clinical status of glaucoma remained stable on maximal medical therapy until 2018 when she conceived. In early 2019, her second pregnancy was confirmed, and the patient noticed a drop in visual acuity in OU as the pregnancy progressed. In addition, bimatoprost eye drops was stopped after conception.

Figure 1.

(a) Optical coherence tomography (OCT) OD revealing preservation of the superior retinal nerve fiber layer (RNFL) and superior ganglion cell layer (GCL) (black arrows). (b) OCT OS revealing complete loss of the RNFL and GCL (black arrows). (c and d) Follow-up OCT showing improvement of RNFL thickness in he temporal quadrants (blue arrow) OD, and in the nasal quadrants (blue arrow) OS, respectively. (e) Fundus photograph taken during third trimester of pregnancy. (f) Baseline visual fields done in 2018 revealing superior arcuate scotoma in OU when Axenfeld–Rieger syndrome was diagnosed. (g) Visual fields 10–2 OD. (h) Visual fields 10–2 OS. RNFL: Retinal nerve fiber layer, GCL: Ganglion cell layer

At presentation in 2019, the best corrected visual acuity was 20/80 and 20/400 in the right eye (OD) and left eye (OS), respectively. Her IOP by applanation was 38 and 32 mm Hg in OD and OS, respectively, despite maximal tolerated medical therapy. The lids, conjunctiva, and lens were normal. The cornea had posterior embryotoxon with iris features showing corectopia and pseudopolycoria OU [Figure 2]. There was evidence of advanced glaucomatous damage [Figure 1a, b, and e] and advanced visual field loss [Figure 1g and h]. Facial examination revealed mild craniofacial dysmorphism. In addition, she suffered from gestational diabetes mellitus. The refractory and progressive nature of glaucoma with useful vision in one eye necessitated immediate surgical intervention. After obstetric consultation and weighting risks to both mother and fetus, a valved glaucoma drainage device (GDD) (Ahmed™ Glaucoma Valve, New World Medical, Inc., Rancho Cucamonga, CA, USA) was implanted in OD under sub-tenon's anesthesia with fetal monitoring in a facility where obstetric emergency services were within reach. The sub-tenon's anesthesia comprised a 4 mL mixture of 2% plain lignocaine and 0.5% plain bupivacaine, and no sedation was required. Precautions were taken intraoperatively to prevent systemic hypotension due to aortic and venacaval compression by the conceived uterus. The patient's hips, abdomen, and thighs were rotated to the left, accomplishing a left down decubitus position when maintaining a normal head position for ophthalmic surgery. The procedure was tolerated well by the patient and the fetus. The postoperative courses were uneventful with IOP in mid-teens during the final follow-up at 18 months postoperative. Topical antibiotic and steroid were started four times daily and were continued for 4 weeks followed by a rapid tapering owing to pregnancy state. A “hypertensive” phase after GDD implantation was anticipated, presumably secondary to a thick-walled bleb over the plate of the implant; therefore, the patient was put on brinzolamide and timolol in OD post-Ahmed glaucoma valve (AGV) implantation.

Figure 2.

(a and b) Slit-lamp examination of OD and OS, respectively, revealing features suggestive of Axenfeld–Rieger syndrome taken post-Ahmed glaucoma valve (AGV) implantation (yellow arrow) in OD. (c) External reservoir of the AGV implant surrounded by a fibrous capsule post implantation in OD. (d) Ologen bleb post-trabeculectomy in OS undergoing scarring

Once the child was delivered, there was resolution of the refractory nature of the glaucoma. In the postpartum period, 1 month after delivery, OS (near-blind eye) was operated with a modified trabeculectomy. A porous collagen-glycosaminoglycan matrix (Ologen^®) biodegradable implant was used. However, bleb scarring still occurred, and the patient was started OS on brinzolamide/timolol fixed combination and bimatoprost at 2 weeks and 1-month postoperative, respectively, to tackle IOP rise related to bleb scarring.

ARS being an autosomal dominant condition necessitated ocular examination of all her children. Upon examination under anesthesia, the patient's 5-year-old daughter did not have ARS, but her newborn son was affected [Figure 3] without any features of glaucoma.

Figure 3.

(a and b) Family screening revealed Axenfeld–Rieger syndrome features for the newly born male in OD and OS, respectively. Horizontal and vertical diameter of cornea was 10 mm OU with axial length of 16.96 mm in OD and 16.58 mm in OS. Intraocular pressure by Perkins tonometer was within normal limits in OU

Discussion

Pregnancy usually results in lower IOP, but this patient with ARS and secondary glaucoma had a significant rise in IOP and glaucoma progression, despite medical therapy during her antenatal period. Hence, surgical management was preferred to lower IOPs and preserve vision, especially in such a functionally monocular patient. Potential mechanisms for otherwise controlled IOP to rise during pregnancy could be combination of paradoxical hormone-induced ocular hypertensive effects, increased episcleral venous pressure, and mild metabolic acidosis due to gestational diabetes.[2]

The risk–benefit ratio was weighed-in during the surgical management of glaucoma during pregnancy.[3] As the supine position is known to cause systemic hypotension in the second and third trimester, care needs to be taken by properly positioning the patient. It was suggested that rotating the patients abdomen, hips, and thighs to the left position helps in preventing systemic hypotension.[4] Group B drugs such as etidocaine, lidocaine, and prilocaine can be used safely in pregnant women, whereas group C drugs such as bupivacaine and mepivacaine can cause fetal bradycardia.[5] General anesthesia poses the risk of low birth weight babies and neural tube defects, especially during exposure in the first trimester.[6]

Subconjunctival and sub-tenon's anesthesia have less systemic absorption than retrobulbar anesthesia.[7] Hence, the valved GDD was implanted in OD under sub-tenon's anesthesia.

In general, goniotomy and trabeculotomy are less successful in ARS due to angle dysgenesis as seen in this patient [Figure 4]. Trabeculectomy in ARS is often complicated by increased incidence of bleb fibrosis and failure. Use of mitomycin-C to prevent bleb fibrosis is relatively contraindicated due to teratogenicity.[8] Moreover, there is a risk of 7%–8% of eyes developing late postoperative endophthalmitis.[9,10] Hence, AGV implantation was planned in OD to reduce IOP, as they have a good long term success rate of 70%–90% at 2 years follow-up with very low incidence of endophthalmitis.[11]

Figure 4.

(a and b) Gonioscopy examination of OD and OS, respectively, revealing angle dysgenesis (taken post-Ahmed glaucoma valve implantation in OD)

In the postpartum period, 1 month after delivery, OS (near blind eye) was operated. Trabeculectomy with Ologen^® was performed with focus on preventing bleb cicatrization without producing adverse effects. Studies have shown that the use of Ologen^® implant produces comparable IOP reduction with trabeculectomy and a lower risk profile when compared to the use of antimetabolites.[12,13,14,15,16,17]

On follow–up, the IOPs remained stable in OU [Table 1], the fundus findings remained stable and the optical coherence tomography thickness of retinal nerve fiber layer [Figure 1c and d] showed minimal improvement on achievement of target pressures.

Table 1.

Follow-up timeline for both eyes

Follow-up	OD (post-AGV implantation) (mm Hg)	OS (post-trabeculectomy with Ologen) (mm Hg)
1 week	17	12
2 weeks	15	22
1 month	17	18
3 months	16	15
6 months	15	13
12 months	13	14
18 months	14	13

Patient was put on brinzolamide and timolol in OD to prevent a possible hypertensive phase post-AGV implantation. Patient was started on brinzolamide with timolol combination and bimatoprost in the OS at two week and one month, respectively, in the postpartum period to tackle IOP rise postoperatively. AGV: Ahmed glaucoma valve

Conclusion

The case describes successful management of refractory glaucoma due to ARS in a pregnant woman in her last trimester. When indicated, glaucoma surgery may be considered in the third trimester for intractable glaucoma to preserve vision with appropriate monitoring of the mother and the fetus.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given her consent for her images and other clinical information to be reported in the journal. The patient understands that her name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.