In Vivo Confocal Imaging of the Conjunctiva as a Predictive Tool for the Glaucoma Filtration Surgery Outcome

PURPOSE: To examine the preoperative conjunctival dendritic cell density (DCD), goblet cell density (GCD), and stromal meshwork reflectivity (SMR) in glaucomatous patients undergoing filtration surgery, using in vivo confocal microscopy (IVCM). METHODS: Sixty-six patients were enrolled. At baseline, IVCM was performed at the site planned for surgery, and was repeated after 12 months at bleb site. Surgery was successful when a one-third reduction of baseline IOP was obtained at the last follow-up. The main outcomes were baseline DCD, GCD, and SMR, and 12 months IOP. The relations between baseline confocal parameters and 12 months IOP were analyzed. RESULTS: Filtration surgery was successful in 43 patients (group 1: complete success, 25; group 2: qualified success, 18), and unsuccessful in 23 patients (group 3). Baseline IOP (mm Hg) was 27.6 ± 2.8, 28.8 ± 4.1, and 27.7 ± 3.2 in groups 1 to 3, respectively. Preoperative DCD and SMR were lower in group 1 compared with groups 2 (P < 0.001, P < 0.05), and 3 (P < 0.001); preoperative GCD was higher in group 1 compared with groups 2 and 3 (P < 0.001). DCD and GCD were also different between groups 2 and 3 (P < 0.05, P < 0.001). At 12 months, IOP reduced by 43.3%, 38.4%, and 15.8% in groups 1 to 3. Twelve-month IOP reduction negatively correlated with baseline DCD and SMR (P < 0.001, r = -0.786; P < 0.05, r = -0.618), and positively with GCD (P < 0.001, r = 0.752). CONCLUSIONS: Preoperative DCD, GCD, and SMR are parameters correlated with the filtration surgery outcome, with DCD presenting the strongest correlation. IVCM of the conjunctiva may represent an imaging tool to predict the surgical success in glaucoma.