Donor corneoscleral buttons: a new source of trabecular meshwork for research

The human trabecular meshwork (TM) is the major site of resistance for aqueous humor outflow. The purpose of this investigation was to determine the suitability of TMs harvested from donor corneoscleral buttons (buttons) for laboratory studies. Histologic examination using light and electron microscopy was performed. Additionally, the effect of incubation in serum free media on histologic appearance was studied. Total RNA extraction was performed on 45 buttons and four whole eyes. Some TMs were used as a source for establishing primary cell cultures of TM endothelial cells. Compared with donor whole eyes, light microscopy showed comparable TM cellularity in the juxtacanalicular and corneoscleral TM; there was some loss of cells in the inner portion of uveal TM that was adjacent to the anterior chamber. The TM cells appeared healthy and structurally normal on transmissive electron microscopy. Usable quantities of total RNA could be extracted from buttons that had been stored up to 5 weeks. The amount of total RNA extracted correlated well with the histologic appearance. Incubation in serum free media did not have an effect on the histologic appearance. All attempts at establishing primary cell cultures were successful. Unused, donor corneoscleral buttons are an excellent source of TM.