Drainage devices provide long-term IOP control in glaucoma, and a recent study found that this holds true even after penetrating keratoplasty (PK), despite the diminishing rate of success. The retrospective study followed 20 eyes of 40 patients for at least 10 years.

At baseline, mean IOP was 34mm Hg, and patients were on an average of 3.2 glaucoma medications. At the last post-op follow-up, mean IOP had decreased to 12.7mm Hg, and medication regimen had decreased to an average of one. Glaucoma was successfully controlled in at least 70% of eyes throughout the follow-up period—sometimes in as many as 88%—and in 68% of eyes at the final follow-up visit.

Corneal grafts, on the other hand, were less successful, with a drop from 74% to 26% clear grafts over 10 years. At the last follow-up, only 17.5% of the grafts remained clear (Table 1).

“A glaucoma drainage device can successfully control intractable glaucoma even after a very long period of time (and) also after PK,” the researchers concluded. “However, the survival of the corneal grafts is low.”

Table 1. Long-term Success of Glaucoma Drainage Device and PK

 Follow-up visitsGlaucoma Drainage DevicePK
 1 88% 74%
 2 88% 63%
 3 85% 45%
 4 80% 45%
5 78% 37%
7 75% 32%
10 70% 26%
 Final 68% 17.5%

Purtskhvanidze K, Saeger M, Frimpong-Boateng,A, et al. Ten-year outcome of glaucoma drainage device surgery after penetrating keratoplasty. J Glaucoma. November 11, 2020. [Epub ahead of print].