Trabeculectomy Specimens


Some ophthalmic pathology laboratories process trabeculectomy specimens routinely. There is roughly up to a 10% incidence of unexpected findings (subclinical iris neovascularization, inflammation, or neoplasm) in such specimens.

Additionally, if scleral spur is identified in the trabeculectomy block, then the surgeon has disinserted the ciliary body from its insertion, creating a cyclodialysis in addition to removing a trabeculectomy block. Discovery of scleral spur tissue in the trabeculectomy block may therefore be helpful in understanding persistent and profound postoperative hypotony.


Preparation by Ophthalmologist

The iris tissue is quite fragile. It may be placed on a flat mount (such as filter paper). It is probably best to avoid placing flimsy iris tissue on surgical sponges which may expand when contacting the fixative, thereby tearing the tissue sample.


Preparation by Ophthalmic Histotechnologist/Cytotechnologist

The trabeculectomy blocks and iris fragments may be quite small. During the grossing procedure, the prosector may wish to place a droplet of eosin on the samples to permit the histology technicians to identify the tissue when it is taken from the tissue processor for embedding.


Issues for the Pathologist


Pathologists should comment on the presence or absence of:
  1. Scleral spur tissue in the trabeculectomy block
  2. Inflammation, exfoliation material, neoplasm, or neovascularization in the iris tissue sample

A neovascular membrane (arrows) lines the surface of the iris. This finding was subclinical and unsuspected before surgery.



More Questions?

If you have more questions about trabeculectomy specimens, please contact one of us:

Ophthalmic Pathologists

Robert Folberg, MD, FCAP, Director

Deepak P. Edward, MD

Consultation Coordinator

Marnie Pomeroy





Information about another test


about us research education laboratory research education laboratory services homepage education information research homepage