[Effect of endocyclophotocoagulation on survival of corneal grafts]

To observe the effect of semiconductor (diode) laser endocyclic-photocoagulation (ECP) on the survival of corneal grafts for patients with uncontrolled refractory glaucoma secondary to penetrating keratoplasty (PKP).

Thirty-four eyes of 34 patients with refractory glaucoma were prospectively assigned to diode laser ECP in 12 eyes, and diode laser ECP with anterior vitrectomy in 22 eyes in Zhongshan Ophthalmic Center from March 2000 to April 2004 as ECP group. Twenty-six eyes of 26 patients were underwent trans-scleral cyclophotocoagulation (TCP) as TCP group. The preoperative and postoperative follow-up parameters evaluated included visual acuity (VA), intraocular pressure (IOP), corneal graft clearance, endothelial cell density (ECD), anterior chamber inflammation, ciliary processes and chamber angle (viewed under ultrasonic biomicroscope, UBM), and the postoperative complications were recorded as well.

In ECP group, a mean of (2.7 +/- 1.3) glaucoma medications was used with mean preoperative IOP value of (40.1 +/- 9.6) mm Hg preoperatively. IOP was decreased (below 21 mm Hg) in 13 eyes (38.2%) 3 months postoperatively. Six months after ECP, decreased IOP (below 21 mm Hg) was obtained in 23 eyes (67.7%). In TCP group, a mean of (2.3 +/- 1.5) glaucoma medications were administrated with mean preoperative IOP value of (41.4 +/- 10.4) mm Hg preoperatively. IOP was decreased (below 21 mm Hg) in 10 eyes (38.5%) 3 months postoperatively. Six months after TCP, decreased IOP (below 21 mm Hg) was obtained in 8 eyes (30.8%). The difference of IOP reduction between these two groups showed no statistical significance 3 months postoperatively (chi(2) = 0.0003, P = 0.986), but it was statistically significant after 6 months (chi(2) = 8.024, P = 0.005). In ECP group, 25 eyes had clear corneal grafts preoperatively, with mean ECD of (1353 +/- 293) cells/mm(2). Postoperative mean ECD was (1013 +/- 170) cells/mm(2). In TCP group, 20 eyes had clear corneal grafts preoperatively, with mean ECD of (1221 +/- 191) cells/mm(2). Postoperative mean ECD was (847 +/- 136) cells/mm(2). The difference of ECD between ECP and TCP group was statistically significant (t = -0.009, P = 0.033). Reactive no-specific inflammation in anterior chamber occurred in 9 eyes (26.5%) in ECP group and 21 eyes (80.8%) in TCP group, which showed statistical significance (chi(2) = 17.376, P = 0.001).

ECP proved more efficacious than TCP in controlling IOP in patients with post-penetrating keratoplasty glaucoma in long-term observation. Compared with TCP, ECP shows less corneal graft endothelial cell loss, and comparatively mild post-ECP uveitis, which improves the survival of corneal grafts greatly.