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 Table of Contents  
Year : 2022  |  Volume : 2  |  Issue : 2  |  Page : 413-415

Spontaneous resolution of hypotony after Aurolab aqueous drainage implant due to fibrous ingrowth

1 Department of Glaucoma, The Eye Foundation, R. S. Puram, Coimbatore, Tamil Nadu, India
2 Department of Ophthalmology & Visual Sciences, Moran Eye Center, University of Utah, Salt Lake City, USA

Date of Submission02-May-2021
Date of Acceptance01-Oct-2021
Date of Web Publication13-Apr-2022

Correspondence Address:
Muralidhar Rajamani
Consultant, Department of Glaucoma, The Eye Foundation, 582A, D. B. Road, R. S. Puram, Coimbatore - 641 002, Tamil Nadu
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijo.IJO_1068_21

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Peritubular leak after glaucoma drainage device implantation causing hypotony can occur with the use of needles with a bore larger than 25 G for creating an entry track for the tube. We report a patient who developed persistent hypotony probably due to peritubular leak after Aurolab Aqueous Drainage Implant implantation using a 22-G needle. The hypotony spontaneously resolved 7 months after surgery due to fibrous ingrowth. High intraocular pressures due to tube blockage were treated with Nd: YAG laser to clear the fibrous ingrowth. Surgeons should be aware of fibrous ingrowth as a complication of using a large-bore needle track for tube insertion.

Keywords: Fibrous ingrowth, glaucoma drainage device, hypotony

How to cite this article:
Rajamani M, Chaya CJ, Ramamurthy C. Spontaneous resolution of hypotony after Aurolab aqueous drainage implant due to fibrous ingrowth. Indian J Ophthalmol Case Rep 2022;2:413-5

How to cite this URL:
Rajamani M, Chaya CJ, Ramamurthy C. Spontaneous resolution of hypotony after Aurolab aqueous drainage implant due to fibrous ingrowth. Indian J Ophthalmol Case Rep [serial online] 2022 [cited 2022 May 24];2:413-5. Available from: https://www.ijoreports.in/text.asp?2022/2/2/413/342867

Glaucoma drainage devices are extensively used in the management of refractory glaucoma. While these devices are very effective, several complications have been reported with their use.[1] Hypotony is not uncommon after implantation of glaucoma drainage devices. It is often transient and may resolve spontaneously. However, persistent hypotony can cause vision loss due to choroidal detachment, choroidal hemorrhage, and macular changes and may need surgical intervention.[2],[3] We report a patient in whom hypotony due to suspected peritubular leak resolved spontaneously due to fibrous ingrowth around the tube. IOP rise due to blockage of the tube was treated by disrupting the ingrowth with Nd:YAG laser.

  Case Report Top

A 68-year-old diabetic male patient presented to us with bilateral gradual progressive decline in vision for the past 6 months. The patient had undergone combined phacoemulsification with IOL implantation and trabeculectomy in both eyes 5 years back. The right eye had undergone a repeat trabeculectomy 2 years back. He had a best-corrected visual acuity of 20/60 OD and 20/200 OS with intraocular pressures (IOP) of 28 mm Hg OD and 26 mm Hg OS. Open angles were noted on gonioscopy. Fundus examination showed advanced glaucomatous cupping OU. Visual fields showed advanced glaucomatous damage OU. IOP was poorly controlled on topical medications.

The patient underwent Aurolab Aqueous Drainage Implant (AADI, Aurolab, Madurai) in the right eye. Tube ligation was done with two 6-0 vicryl® sutures and confirmed by injecting a balanced salt solution. A 23-G needle was used to enter the ciliary sulcus under a scleral flap. The needle track had to be enlarged with a 22-G needle for tube insertion. No vitreous disturbance was noted. The remaining length of the tube was covered with a donor scleral graft. Postoperatively, he was placed on a 3-month tapering regime of topical loteprednol, moxifloxacin, and atropine. Ten days later, he had an IOP of 2 mm Hg OD. The anterior chamber was well-formed with 1+ cells. No bleb was noted in the perilimbal area. Shallow serous choroidal detachment was noted in two quadrants. Antiglaucoma medications were stopped and topical difluprednate 5 times a day was instituted. The hypotony persisted and 3 months after surgery, he had a vision of 20/120 OD and 20/200 OS with an IOP of 2 mm Hg OD and 16 mm Hg OS. It was judged that he will not cooperate for injection of 1.4% sodium hyaluronate on the slit lamp. Surgical exploration under local anesthesia was advised. It was planned to narrow the tube lumen using the technique described by Vergados et al.[1] if no leak was found. Surgery could not be done because of uncontrolled blood sugar levels, and the patient did not return for follow-up on the specified appointment date.

The patient was reviewed 4 months later and had a a vision of 20/60 OD and 20/200 OS and IOP of 12 mm Hg OD and 21 mm Hg OS. A fibrous membrane was seen blocking the tube orifice [Figure 1]. He presented a month later with pain in the right eye. The fibrous ingrowth surrounding the tube could be viewed on gonioscopy and was noted to be restricted to tube orifice and peritubular area only. The IOP was 46 mm Hg OD and 18 mm Hg OS. The fibrous membrane was lysed with Nd: YAG laser. Three months later, IOP was 7 mm Hg OD and 23 mm Hg OS. A year later, the IOP was 12 mm Hg OD and 20 mm Hg OS. The tube was patent and the fibrosis had completely retracted [Figure 2]a and [Figure 2]b. The patient has maintained a stable course for over a year now after resolution of hypotony.
Figure 1: Anterior segment photograph of the right eye 7 months after surgery showing blockage of the tube orifice with fibrous ingrowth

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Figure 2: (a) Anterior segment photograph of the right eye immediately after Nd:YAG laser disruption of the fibrous membrane. The bleeding is from the iris due to laser shots. (b) Anterior segment photograph of the right eye 3 months after Nd:YAG laser showing a patent tube orifice and retraction of the fibrous ingrowth

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  Discussion Top

In nonvalved implants, flow is restricted in the immediate postoperative period by a temporary ligature to allow a fibrous capsule to form around the implant. Hypotony may occur in the early postoperative period due to peritubular leak, slippage of the ligature, and aqueous hyposecretion (secondary to inflammation). In some patients, the fibrous capsule forms late or is severely deficient. This causes hypotony once the tube ligature lyses. Inflammation suppresses aqueous formation and causes hypotony. Hypotony sets off a vicious cycle by causing a breakdown in blood–aqueous barrier and dysfunction of the ciliary epithelium.[2],[3],[4],[5]

We suspected peritubular leak in our case as the tube insertion point had to be enlarged. Resolution after fibrous ingrowth also supported peritubular leak as the main reason for hypotony. As two ligatures were placed around the tube, ligature malfunction was considered unlikely. Had the hypotony been due to loosening of the tube ligatures, it would have resolved after a capsule formed around the plate of AADI®. Lim et al.[4] noted a higher incidence of hypotony with the use of a 23-G needle when compared to a 25-G needle and attributed this to peritubular leak. A bleb was not seen in our case possibly because the whole length of the tube was covered by scleral flap/scleral patch graft.

Peritubular leak can be managed by sealing the leak with autologous tenon's or closing the entry site and reinserting the tube with a narrower needle track. Some relief of hypotony may be obtained by injecting 1.4% sodium hyaluronate on the slit lamp. A temporary or permanent ligature may be placed around the tube to stem overfiltration.[1],[5] Rare cases of persistent hypotony may need removal of the implant.[2]

Fibrous ingrowth blocking the tube orifice in a 61-year-old patient was reported by Shazly et al.[6] after multiple intraocular surgeries. The dense fibrous ingrowth was surgically dissected and a Descemet's stripping automated endothelial keratoplasty was performed. The fibrous ingrowth in our patient was relatively mild and was likely caused by enlargement of the entry for tube placement. As fibrous ingrowth can progress and become more extensive as in the patient reported by Shazly et al.,[6] it behoves the surgeon to monitor the extent closely with gonioscopy and/or ultrasound biomicroscopy. A beneficial effect of the fibrous ingrowth was the spontaneous resolution of hypotony. Subsequent laser of the fibrous membrane resulted in prompt retraction.

  Conclusion Top

To sum up, surgeons should be aware of fibrous ingrowth as a complication of tube insertion through a large needle track. Prompt treatment with Nd:YAG laser can result in retraction of the fibrous ingrowth and potentially prevent a more extensive ingrowth that could damage anterior segment structures.

It is preferable to use a 23-G needle track for tube insertion. If a larger bore needle is used to facilitate entry, the patient should be followed up closely to detect and treat fibrous ingrowth early. Gonioscopy/ultrasound biomicroscopy can be used to gauge the extent of fibrous ingrowth.

Declaration of patient consent

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

Financial support and sponsorship

Dr. Craig J Chaya supported in part by an Unrestricted Grant from Research to Prevent Blindness, Inc., New York, NY, to the Department of Ophthalmology & Visual Sciences, University of Utah. This study has not been funded by anyone.

Conflicts of interest

There are no conflicts of interest.

  References Top

Vergados A, Mohite AA, Sung VCT. Ab interno tube ligation for refractory hypotony following non-valved glaucoma drainage device implantation. Graefes Arch Clin Exp Ophthalmol 2019;257:2271-8.  Back to cited text no. 1
Stein JD, McCoy AN, Asrani S, Herndon LW, Lee PP, McKinnon SJ, et al. Surgical management of hypotony owing to overfiltration in eyes receiving glaucoma drainage devices. J Glaucoma 2009;18:638-41.  Back to cited text no. 2
Lim KS. Control and optimisation of fluid flow in glaucoma drainage device surgery. Eye (Lond) 2018;32:230-4.  Back to cited text no. 3
Sheng Lim K, Garg A, Cheng J, Muthusamy K, Beltran-Agullo L, Barton K. Comparison of short-term postoperative hypotony rates of 23-gauge vs 25-gauge needles in formation of the scleral tract for Baerveldt tube insertion into the anterior chamber. J Curr Glaucoma Pract 2018;12:36-9.  Back to cited text no. 4
Chiam PJ, Chen X, Haque MS, Sung VC. Outcome of fixed volume intracameral sodium hyaluronate 1.4% injection for early postoperative hypotony after Baerveldt glaucoma implant. Clin Exp Ophthalmol 2018;46:1035-40.  Back to cited text no. 5
Shazly TA, To LK, Conner IP, Espandar L. Intraoperative optical coherence tomography-assisted descemet stripping automated endothelial keratoplasty for anterior chamber fibrous ingrowth. Cornea 2017;36:757-8.  Back to cited text no. 6


  [Figure 1], [Figure 2]


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