New Orleans—Late-onset bleb leakage needs to be controlled to avoid such complications as blebitis or bleb-related endophthalmitis, which can result in poor visual outcome, reported Philip P. Chen, MD, during the glaucoma subspecialty day meeting at the American Academy of Ophthalmology annual meeting.
Bleb leaks occur in 2% to 9% of cases at 2 to 3 years after surgery, according to retrospective reports. DeBry and others calculated a rate as high as 18% at 5 years using Kaplan-Meier analyses. They also found that blebitis occurred at a rate of 6% and endophthalmitis at a rate of 7.5% at 5 years, said Dr. Chen, associate professor, department of ophthalmology, University of Washington, Seattle.
Conservative therapy includes maximal aqueous suppression using such agents as dorzolamide HCl and timolol maleate (Cosopt, Merck) and brimonidine tartrate 0.15% (Alphagan P, Allergan) or apraclonidine 0.5% (Iopidine, Alcon Laboratories) for at least 1 month. Pressure patching with an oversize contact lens can be considered, although some patients cannot tolerate this approach, he noted.
More invasive approaches may be tried, such as autologous blood injection, compression sutures, Nd:YAG laser treatment, and bleb needling, Dr. Chen explained.
Autologous blood injection can be performed using topical anesthesia at the slit lamp, he said. About 0.5 to 1 ml of autologous blood is injected into and around the bleb.
"The main problem (with this technique) is that the success rate can be variable," Dr. Chen said. "Bleb leaks can recur in the same location or in a different location because the underlying blood architecture is generally not changed."
Compression sutures can be used to compress the bleb leak. They are passed through the anterior cornea in front of the bleb and then passed through the episclera posterior to the bleb, he continued.
YAG laser treatment applied in the continuous-wave mode is another option to stop bleb leakage.
"The laser can incite inflammation in the bleb and seal it," Dr. Chen said.
"However, this requires retrobulbar anesthetic, and in addition, the continuous-wave type of YAG laser is not commonly available," he said.
Bleb needling can be employed to reduce tension on the thinnest areas of the bleb and allow for bleb healing, Dr. Chen noted.
Conjunctival advancement In some cases, the surgeon may perform conjunctival advancement in the operating room. It requires excision of the bleb and the conjunctiva is pulled down.
"Then the limbus is freshened and the conjunctiva is attached with mattress and wing sutures," Dr. Chen explained.
In about 10% of cases, glaucoma surgery is needed and 40% to 50% will need more medical therapy to control their IOP, he said.
Conservative therapy is not always effective, as shown in a study by Burnstein et al. published in 2002. They found that after 1 month the bleb leaks sealed in only 54% of the cases with conservative approaches. In addition, there were more failures later, Dr. Chen noted.
"Conservative therapy was significantly less successful at closing the leak than conjunctival advancement in the OR," he said. "However, after surgical revision, as seen in other studies, 44% need more medications, 9% had uncontrolled IOP, and 6% had vertical diplopia."
Other invasive procedures for bleb leaks include conjunctival autografts and closure of the bleb with placement of a glaucoma drainage device in another quadrant, Dr. Chen said.