Corneal endothelial cell changes after trabeculectomy and deep sclerectomy.

PURPOSE

To compare the effect of trabeculectomy and deep sclerectomy on the corneal endothelium.

METHODS

This prospective comparative study investigated 62 eyes of 62 patients scheduled for a single trabeculectomy (n=18), a single deep sclerectomy (n=14), a combined trabeculectomy and phacoemulsification (n=11), or a combined deep sclerectomy and phacoemulsification (n=19). Exclusion criteria were history of corneal disease, ocular trauma, inflammation, or previous glaucoma or cataract surgery. Preoperative, 3-month and 1-year postoperative noncontact specular microscopies were performed on central and superior corneas. Endothelial cells were counted with a computer-assisted analyzer.

RESULTS

In central cornea, a statistically significant postoperative endothelial cell loss was found after trabeculectomy and deep sclerectomy (alone and combined with cataract extraction) at 3 and 12 months. Cell loss was 7% after penetrating surgery and 2.6% after nonpenetrating surgery (noncombined surgeries). This difference in cell loss was statistically significant. Cell loss increased significantly over the course of the study at 12 months (9.6% and 4.5%, respectively). Cell loss was also significantly higher after trabeculectomy than sclerectomy in upper cornea only in noncombined surgeries. No statistically significant difference in coefficient of variation of cell size (CV) and percentage of cell hexagonality (Hex %) was noted.

CONCLUSIONS

Endothelial cell loss was moderate 3 and 12 months after glaucoma surgery. However, it was greater after trabeculectomy, suggesting less corneal damage after deep sclerectomy. This observation deserves further clinical study.