Channels: Glaucoma | Posted 10/26/2010
This patient had undergone a trabeculectomy with mitomycin (MMC) in both eyes more than 4 years ago and has recently been suffering from recurrent bleb leaks and infections. As can often happen, especially with the older approach of the day of limbal-based surgery (conjunctival incision in the fornix) with the MMC applied over a more localized area, the bleb enlarged and thinned over the years. This is perhaps less of an issue with the trend toward fornix-based surgery (conjunctival incision at the limbus) and applying the MMC over a larger area that is well back from the limbus to encourage low diffuse bleb formation. However, as there are many patients whose blebs will need revising in order to prevent potentially blinding endophthalmitis, we need to have a few strategies in our surgical arsenal.
There are several different approaches to consider. One can just excise the epithelium and advance fresh conjunctiva, remove the whole bleb with or without suturing the scleral flap, or, as in this example, suture donor sclera atop the scleral flap or an extra layer of protection. The technique should vary depending on your goals for the particular patient.
For this particular patient, in whom I opted to suture a scleral patch graft over the scleral flap, most of the decisions regarding the approach were decided upon DURING the surgery. This meant having already ordered donor sclera material to be present in the operating room in case it is needed. This is one of the rare times I opted to use it. However, after beginning to suture the donor sclera on either side, I changed my mind and opted instead to suture just the anterior edge of the donor sclera. My rationale here was that I still want to achieve some flow through the scleral flap and not shoot his eye pressure completely out of control. This will help prevent flow anteriorly into and from the tear film but could still allow posterior flow and the creation of a new bleb. I also opted to run the conjunctival suture instead of my usual winged suture at each end with horizontal mattress centrally.