A Comparison of Sequential Glaucoma Drainage Device Implantation Versus Cyclophotocoagulation Following Failure of a Primary Drainage Device

To compare sequential glaucoma drainage device (GDD) implantation with transscleral diode cyclophotocoagulation (CPC) following failure of a primary GDD. A retrospective review of all patients who underwent GDD implantation at a single institution over 10 years. Patients who required an additional GDD and/or CPC were analyzed. Success was defined as absence of loss of light perception, reoperation for glaucoma, and intraocular pressure (IOP) >21 or <6 at 2 consecutive visits after an initial 3-month period. Thirty-two patients received sequential GDD. Twenty-one underwent CPC. Cohorts were statistically similar in regards to age, sex, race, and number of previous surgeries. Preoperatively, the GDD cohort had a lower IOP and better visual acuity. The mean length of follow-up was 37.9 months for the GDD group and 46.3 months for CPC. Both procedures significantly reduced IOP; however, CPC led to a greater reduction (P=0.0172). Survival analysis found the 5-year probability of surgical success to be 65.3% for sequential GDD and 58.0% for CPC (P=0.8678). No cases of phthisis occurred in either group. There were 2 cases of endophthalmitis (6.3%) in the GDD group, and none in the CPC group. In eyes without preexisting corneal edema, estimated corneal decompensation probability at 3 years was 31.6% for GDD and 6.7% for CPC (P=0.0828). Sequential GDD and CPC are both effective at reducing IOP following the failure of a primary GDD. CPC after GDD failure warrants further investigation as it led to a greater reduction in IOP with fewer serious adverse events.