Surgeons can consider a relatively simple, inexpensive, efficient and accessible incision-free procedure to preserve blebs.
In the past, attempts at bleb repair after trabeculectomy and introduction of the use of mitomycin C (MMC) to improve surgical success rates resulted in blebs that were avascular and prone to leaks. According to Prof. Neeru Gupta, chief of glaucoma at the University of Toronto, Canada, and president-elect of the World Glaucoma Association, this situation is a “time bomb”. She said: “Left unchecked, it can lead to blebitis and possibly endophthalmitis, and myriad other problems, such as hypotony with associated anatomic disruptions such as vision-blurring corneal striae, shallow anterior chambers, buildup of excess fluid leading to dome-shaped choroidals and hypotony maculopathy.”
Techniques that have attempted to address the problem of leaky blebs include conservative treatment with antibiotics; aqueous suppressants; steroids; collagen shields; bandage contact lens; pressure patches; cyanoacrylate tissue glue; autologous blood; and argon laser or Nd:YAG laser. The microsurgical approaches include bleb resuturing, and bleb excision and conjunctival advancement with or without various grafting techniques.
Despite all this, no procedure stands out as effective. “Despite the number of attempted procedures, we continue to struggle with managing bleb leaks,” Prof. Gupta said.
Novel bleb leak management
Prof. Gupta developed the minimally invasive conjunctival surgery incision-free procedure to address late-onset bleb leaks close to the limbus. A patient had a history of high myopia, advanced pigmentary glaucoma, retinal detachment treated with pars plana vitrectomy and later with pneumatic retinopexy and cryotherapy. They had used multiple glaucoma medications for advanced glaucoma, thin corneas, bilateral cataracts and had remaining central islands of vision of 20/60 to 20/70.
Prof. Gupta performed bilateral trabeculectomies with MMC. Vision was stable with intraocular pressures (IOPs) of 8–10 mm Hg bilaterally. In 2012, however, the vision in the left eye decreased to 20/100 with an IOP of 2 mm Hg and an avascular leaking bleb. Three days later, the vision was 20/200 with an IOP of 0 mm Hg.
In surgery, Prof. Gupta acted to address this situation without undoing the previous treatments. Instead of excising the bleb and covering the area with conjunctiva, she injected subconjunctival lidocaine above the bleb.
She described the conjunctival epithelium as highly voluminous and able to move freely. With gentle tugging and without disturbing Tenon capsule, she pulled a sizable area of the conjunctival tissue to the limbus over the leaking area and put in a series of stitches (typically three to four) without using a great deal of pressure that resulted in a sealed wound.
“This was a short, incision-free procedure,” she said of this first such case. The patient has done well during the ensuing 8 years. Prof. Gupta reported that she has performed this procedure in 14 cases and reported the results in the American Journal of Ophthalmology.1
In all cases, the patients have remained stable and medication-free from 2 weeks to 5 years later. She said that with time the transposed conjunctival tissue becomes translucent and seems to take on the characteristics of the early bleb that was leaking.
Prof. Gupta enumerated the surgical benefits of this procedure. “It is short and incision free with good success; the bleb is preserved; the procedure is relatively simple, inexpensive, efficient and accessible; and the patients are comfortable postoperatively and can return to normal activities,” she said. “They leave after the surgery with an antibiotic and a steroid. She advised that studies are needed to determine the long-term outcomes.
Neeru Gupta, MD, PhD, MBA
Prof. Gupta has no financial interest in this subject matter.
Gupta N. Incision-free minimally invasive conjunctival surgery (MICS) for late-onset bleb leaks after trabeculectomy (an American Ophthalmological Society thesis). Am. J. Ophthalmol. 2019;207:333-342.