Surgical Reduction of Symptomatic, Circumferential, Filtering Blebs

We describe methods and outcomes of surgical reduction of symptomatic, circumferential, filtering blebs after trabeculectomy with antifibrotic agents. The medical records of 15 eyes of 14 patients with symptomatic, circumferential blebs who underwent surgical bleb reduction for bleb dysesthesia under topical anesthesia were reviewed. Each bleb was incised segmentally and the cut edges of the conjunctiva and Tenon capsule were sutured to the underlying sclera. Outcome measures included symptomatic relief, retention of bleb function, and intraocular pressure maintenance. Fourteen eyes had successful reduction of bleb size, symptomatic relief, and cosmetically acceptable appearance. One eye continued to have dysesthesia and 1 had a transient bleb leak that resolved spontaneously. Surgical reduction of circumferential, symptomatic, filtering blebs is a safe and effective technique to reduce bleb dysesthesia and improve cosmesis without loss of bleb function.

Bleb dysesthesia refers to burning, foreign body sensation, tearing, pain, or ocular discomfort in an eye with a filtering bleb. Large blebs interfere with lid closure, which leads to improper tear film distribution in the area of the bleb, corneal drying, epithelial defects, dellen, and bubble formation at the bleb-cornea interface. In a prospective study, Budenz et al¹ reported higher dysesthesia scores in eyes with filtering blebs as compared with the control eye. They also reported an inverse correlation between percentage of the bleb covered by the lid and dysesthesia. Sanders et al² documented a higher incidence of discomfort (25%) and dellen formation (30%) in patients with nasal blebs. Soong and Quigley³ reported 9 cases (9%) of dellen in a series of 97 trabeculectomies, 2 of which progressed to develop corneal ulcers. Almost all of the dellen occurred in eyes with large filtering blebs. They were all managed conservatively using lubricants and tears.

Methods to manage these symptomatic blebs have included use of lubricants, Nd:YAG (neodymium: yttrium aluminum garnet) laser,⁴ argon laser,⁵ compression sutures,⁶ bleb window cryopexy,⁷ surgical excision,⁸ and bleb reduction.⁹ Rahman and Thaller¹⁰ described a procedure they termed bleb-limiting conjunctivoplasty for treatment of circumferential filtering blebs. We have had excellent results using a similar technique, performed primarily for bleb dysesthesia, and present herein the results in 15 eyes of 14 patients.

After approval by The New York Eye and Ear Infirmary Institutional Review Board for Human Research, a retrospective review of the medical records of all operating room procedures between January 2000 and October 2004 coded as bleb revision was conducted. Fifteen eyes of 14 patients who had undergone trabeculectomy with antifibrotic agents and subsequently developed symptomatic, crescentic blebs and underwent bleb reduction using the technique described later were identified. In all eyes involved, the filtering blebs were thin and had the appearance of typical blebs located within the Tenon capsule and were neither simply chemosis or loculated blebs.

All surgery was performed by 2 of us (R.R. and J.L.) and had at least 3 months of follow-up. The indication for surgical intervention was bleb dysesthesia (13 eyes), poor cosmesis (1 eye), and dysesthesia with fluctuating vision (1 eye). Preoperative conservative measures included use of lubricants in all patients and punctum plugs in 1 patient. Two patients also used hypertonic saline. Medical records were reviewed for preoperative clinical and demographic characteristics, including glaucoma diagnosis, date and type of filtration surgery, antifibrotic used, indications for bleb reduction, surgical technique, and postoperative outcome, including visual acuity, intraocular pressure (IOP), number of glaucoma medications, reoperation for a similar indication, and complications related to surgery. The postoperative visual acuity was considered unchanged if it was within 1 line of the preoperative visual acuity. Success criteria were defined as subjective resolution of symptoms and maintenance of IOP with no subsequent surgical intervention. Results are given as mean ± SD where applicable.

All surgery was performed under topical anesthesia with or without local infiltration. An 8-0 polyglactin traction suture was placed through clear cornea adjacent to the superior limbus and the eye rotated to expose the upper portion of the bleb when necessary to enhance exposure (Figure 1). A paracentesis was made at the temporal horizontal meridian. A 75 blade was used to make an incision through the bleb at the 10:30 or 1:30 position and carried down to the sclera (Figure 2). The anterior chamber remained formed during all procedures. Balanced salt solution was used to reform the anterior chamber if necessary. Polyglactin sutures (8-0 or 9-0) were used to reappose the excised edges of the conjunctiva and Tenon capsule to the sclera (Figure 3 and Figure 4). Occasionally, a tapered needle was used to suture the conjunctival edges to the sclera. No leaks were observed at the end of the procedure. The traction suture was removed and topical or subconjunctival steroids and antibiotics were administered to all patients. A bandage contact lens to cover exposed sutures was inserted in 4 eyes.

Patient characteristics and demographics are listed in Table 1. The mean ± SD age at the time of surgery was 67.6 ± 9.5 years (range, 51-81 years). All eyes had circumferential blebs after trabeculectomy with adjunctive antifibrosis therapy. Results are listed in Table 2. Mitomycin C was used intraoperatively in 11 eyes, 5-fluorouracil was administered subconjunctivally to 3 eyes postoperatively, and 1 eye was treated in an experimental protocol with a new antiscarring agent. Seven patients underwent trabeculectomy with a limbus-based conjunctival flap and 8 received a fornix-based conjunctival flap. The mean ± SD time between trabeculectomy and revision was 2.6 ± 3.0 years (range, 3 months-8.6 years). In patients with a limbus-based conjunctival flap, mean ± SD time from trabeculectomy to revision was 2.2 ± 2.9 years, whereas in patients with a fornix-based conjunctival flap, it was 3.4 ± 3.2 years (P = .50). The mean ± SD IOP was 9.4 ± 4.7 mm Hg prior to revision, 9.2 ± 5.1 mm Hg (P = .90, paired t test) at 1 month postrevision, 9.2 ± 5.0 mm Hg (P = .90) at 3 months, and 10.2 ± 6.6 mm Hg (P = .70) at 1 year. No antiglaucoma medications were necessary preoperatively or postoperatively. Ptosis repair was performed in 1 eye 11 months after the reduction surgery. Fourteen eyes (93.3%) experienced relief of symptoms and were classified as successes. One patient (6.7%) continued to have dysesthesia. One eye had a bleb leak that resolved spontaneously. The patient operated on for poor cosmesis was satisfied postoperatively. Intraocular pressure and visual acuity were maintained in all eyes. Bleb extension did not occur and repeat surgical intervention was not required in any eye. Preoperative and postoperative photographs of a patient at day 1 and at 3 months are shown in Figures 5, 6, and 7.

The widespread use of adjunctive antifibrosis chemotherapy at the time of trabeculectomy has increased the incidence of formation of avascular, thin-walled blebs with potential for leakage,^11,12 endophthalmitis,¹² and excessive filtration.^13,14 Patients with excessive filtration may experience constant foreign body sensation associated with excessive tearing and sensitivity to light.¹⁵ These symptoms, known as bleb dysesthesia, occur more frequently in large blebs,^1,5,16 exuberant circumferential blebs,¹⁷ and blebs that have extended onto the corneal surface.^8,18

Topical lubrication is the initial treatment for bleb dysesthesia and provides adequate relief of symptoms for most patients. Other attempts at remodeling large blebs include argon laser⁵ and Nd:YAG laser.¹⁹

Various surgical techniques for modification of symptomatic, overhanging blebs have been reported. Blebs can be surgically trimmed from the cornea with successful relief of symptoms and improvement in visual acuity.^8,18,20 El-Harazi et al⁷ described bleb window cryopexy in 9 patients with a success rate of 89%. Bleb reduction was described by La Borwit et al⁹ in 11 patients who complained of dysesthesia. All were asymptomatic after the reduction surgery; however, 5 patients subsequently required a second bleb reduction procedure. Van de Geijn et al²¹ reported an 86% success rate using a revision technique for oversized and leaky blebs involving bleb excision with conjunctiva and Tenon advancement; 48% eventually required topical glaucoma medications. Dehiscence of the conjunctiva-Tenon flap occurred in 1 eye, leak occurred in 2 eyes, and 3 eyes required a second revision. Schnyder et al²² used free conjunctival autologous grafts in 2 patients with symptomatic blebs. Both patients had good postoperative IOP control, but the technique is both technically demanding and time-consuming. Catoira et al²³ described conjunctival flap advancement over existing blebs in 3 dysesthetic eyes. Rahman and Thaller¹⁰ described the use of bleb-limiting conjunctivoplasty in 4 eyes of 2 patients with symptomatic blebs. They were required to repeat the procedure in 1 eye because of extension of the bleb.

Fornix-based conjunctival flaps may provide more diffuse, less elevated blebs¹⁴ that are less likely to encroach on the limbus as compared with the limbus-based conjunctival flaps.¹⁶ The latter are limited by scar formation at the conjunctival entry site, preventing posterior movement of aqueous and forcing elevation closer to the limbus.

In the current study, we were able to diminish the interpalpebral exposure of the bleb, thereby reducing the symptoms in our patients. Even if the bleb size was reduced nasally and/or temporally, we did not notice any further elevation in bleb height postoperatively, although we did not actively measure this parameter. Although filtering blebs obtained through the use of antifibrotic agents are more prone to develop leaks, blebitis, and endophthalmitis than blebs obtained with trabeculectomy without antifibrosis use, we did not experience these late bleb complications in our patients. Although our follow-up is short, the lack of recurrent dysesthesia or reoperation is encouraging and suggests that the current technique is useful in the treatment of these difficult patients.

Correspondence: Robert Ritch, MD, Glaucoma Service, The New York Eye and Ear Infirmary, 310 E 14th St, New York, NY 10003 (ritchmd@earthlink.net).

Submitted for Publication: February 9, 2005; final revision received May 29, 2005; accepted June 21, 2005.

Funding/Support: This study was supported in part by the William Endico Research Fund of the New York Glaucoma Research Institute, New York, NY.

Financial Disclosure: None.