Improving Visualization During Bleb Needling

Bleb needling success is often dependent on visualization of the scleral flap after trabeculectomy or the implant after microinvasive bleb surgery.

When visualization is difficult, the use of a Hoskins lens allows me (G.M.) to see the target of the needling by flattening the overlying tissues and blanching the vessels. I prefer a Hoskins lens to other suture lysis lenses because it allows visualization of the surrounding tissues. This enables me to mark the position of the flap or implant once the lens is removed.

This maneuver can help me to decide whether to attempt the needling or to perform an open bleb revision. If the target is not well visualized with the lens, I usually forgo the needling and proceed with an open revision. The same technique can be used to visualize scleral flaps and Xen Gel Stent (AbbVie) and Preserflo MicroShunt (Santen) implants.

A sterilized Hoskins lens can also be used during the needling procedure itself; it allows visualization of the target (flap or implant) and the needle tip underneath the tissues. This approach was previously described by Hayashi in 1995.¹ Care must be taken when advancing the needle to avoid conjunctival buttonholes. Ideally, the lens should be removed while advancing the needle and then reapplied to check the positioning relative to the target.