Potential artifacts in scanning electron microscopy of the trabecular meshwork in glaucoma.

We examined the trabecular meshwork surface by scanning electron microscopy to investigate possible artifacts appearing during collection and preparation of trabeculectomy specimens. As controls, trabecular tissue samples from normal and glaucomatous patients were dissected from whole eyes obtained at enucleation or at autopsy. Our results suggest that the major contaminants are released during decompression of the globe at trabeculectomy; these consist of an amorphous substance, a fibrillar material, and, occasionally, red blood cells. Small tissue samples may also abe contaminated by the conducting adhesive used to fasten them to metal stubs. This silver paint may coat the surface of the meshwork and appear to be a smooth substance blocking the outflow of aqueous humor. We were unable to confirm the finding reported by others that an amorphous blocking material is present in the trabecular interstices in patients with open-angle glaucoma.