Comparison of bleb morphologies between phacoemulsification combined with Ex-PRESS mini shunt implantation, phacotrabeculectomy and trabeculectomy alone: a two-year retrospective in vivo confocal microscopy study

Abstract

Background: To compare the bleb morphologies of phacoemulsification combined with Ex-PRESS implantation (Phaco-ExPRESS), phaco trabeculectomy (Phaco-Trab), and trabeculectomy (Trab) in postoperative two years.

Methods: Patients with primary open-angle glaucoma (POAG) with or without cataracts were included in this study. All patients underwent surgeries of either Phaco-ExPRESS, Phaco-Trab, or Trab. The morphologic structures of the filtering bleb, including microcysts area, hyperreflective dot density, and stromal connective tissue under in vivo confocal microscope (IVCM), were compared between the three groups. The data were collected preoperatively and postoperatively at 2 weeks, 1 month, 3 months, 6 months, 12 months, 18 months, and 24 months.

Results: Eighty-nine eyes from 89 patients were enrolled, including 32 in the Phaco-ExPRESS group, 25 in the Phaco-Trab group, and 32 in the Trab group. In a 24-month follow-up, bleb morphologies in Phaco-ExPRESS were similar to the Trab group. The area of epithelial microcysts was significantly increased in Phaco-ExPRESS and Trab groups while significantly decreased in Phaco-Trab. At postoperative 24 months, the complete success rate was 65.1% in Phaco-ExPRESS, 32.0% in Phaco-Trab, and 59.4% in the Trab group (P = 0.03). The phaco-Trab group had more postoperative anti-glaucoma medications than the other two groups (P < 0.05).

Conclusions: Phaco-ExPRESS group and Trab group had similar blebs morphologies in IVCM, with larger microcyst area, looser connective tissue, and less inflammation than Phaco-Trab, indicating that the function of blebs in the Phaco-ExPRESS and Trab group, was more potent than that of Phaco-Trab. All these surgical methods provided adequate IOP control, but Phaco-Trab required more anti-glaucoma medications.

Keywords: Glaucoma drainage implant; In vivo confocal microscopy; Phacoemulsification; Primary open angle glaucoma; Trabeculectomy.

Fig. 1

Assessment of filtering blebs. This figure showed the assessment of filtering bleb by slit-lamp, anterior segment optical coherence tomography (AS-OCT) and in vivo confocal microscope (IVCM).The striping phenomenon (red arrows), which showed multiple parallel hyperreflective areas inside the presumed Tenon’s layer, was recorded in each filtering bleb. After taking AS-OCT photograph, scanning involving the 5 sites, numbered 1 to 5 in the slit-lamp photograph, was conducted by IVCM. The AS-OCT scanning was taken across the blue line, as shown in the slit-lamp photograph. For each site, the microcysts area (white arrows) and hyperreflective dots (blue arrows) in the epithelium (E1-E5) and connective tissue in the stroma (S1-S5) were recorded for evaluation

Fig. 2

Kaplan-Meier survival analysis. The Kaplan-Meier survival analysis of qualified and complete success. Qualified success was defined as IOP < 18 mmHg with or without anti-glaucoma medication; complete success was defined as IOP < 18 mmHg without anti-glaucoma medication. P < 0.05 was considered as statistically significant. The results showed higher cumulative probability of qualified success in the Phaco-ExPRESS group than in the Phaco-Trab group. For complete success, both the Phaco-ExPRESS and the Trab group showed high cumulative probability of success than the Phaco-Trab group

Fig. 3

Epithelial microcysts area of filtering blebs. The epithelial microcysts area of the three groups at postoperative 2 weeks (2 W), 1 month (1 M), 3 months (3 M), 6 months (6 M), 12 months (12 M), 18 months (18 M), 24 months (24 M). P < 0.05 was considered as statistically significant. Statistically significant between Phaco-Trab vs. Trab group, Phaco-ExPRESS vs. Phaco-Trab group, and Phaco-ExPRESS vs. Trab group were marked as †, ‡, and §, respectively. The Phaco-ExPRESS group showed increased epithelial microcysts area from 1 month to 3 months and 6 months to 12 months (p < 0.05), and the Trab group showed increased epithelial microcysts area from 2 weeks to 3 months (p < 0.05) postoperatively and remained steady from 3 months to 24 months (p > 0.05). However, the Phaco-Trab group showed decreased epithelial microcysts area from 3 months to 12 months (p < 0.05). For comparison between the three groups, the Phaco-Trab group showed smaller microcysts area than the other two groups from postoperative 3 months to 24 months, while the epithelial microcysts area of the Phaco-ExPRESS group was similar to that of the Trab group from postoperative 2 weeks to 24 months

Fig. 4

Density of hyperreflective dots in filtering blebs. The hyperreflective dot density of the three groups at postoperative 2 weeks (2 W), 1 month (1 M), 3 months (3 M), 6 months (6 M), 12 months (12 M), 18 months (18 M), 24 months (24 M). P < 0.05 was considered as statistically significant. Statistically significant between Phaco-ExPRESS vs. Phaco-Trab group, Phaco-Trab vs. Trab group, and Phaco-ExPRESS vs. Trab group were marked as †, ‡, and §, respectively. The Phaco-ExPRESS group showed decreased in hyperreflective dot count from postoperative 6 months to 12 months, while the Phaco-Trab group did not show decreased in hyperreflective dot until 12 months postoperatively. The Trab group showed no significant differences in hyperreflective dot count among different time points. For comparison between the three groups, the Phaco-Trab group showed higher hyperreflective dot count than the Trab group from 2 weeks to 12 months postoperatively. The Phaco-ExPRESS group showed less hyperreflective dot count than the Phaco-Trab group from 3 months to 12 months postoperatively

Fig. 5

Percentage of filtering blebs with connective tissue grade ≤ 2. The percentage of filtering blebs with connective tissue grade ≤ 2 in the three groups at postoperative 2 weeks (2 W), 1 month (1 M), 3 months (3 M), 6 months (6 M), 12 months (12 M), 18 months (18 M), 24 months (24 M). P < 0.05 was considered as statistically significant. Statistically significant between Phaco-ExPRESS vs. Phaco-Trab group, Phaco-Trab vs. Trab group, and Phaco-ExPRESS vs. Trab group were marked as †, ‡, and §, respectively. The Phaco-ExPRESS and the Trab group showed a higher percentage of filtering blebs with connective tissue ≤ 2 than the Phaco-Trab group from 3 months to 24 months postoperatively

Fig. 6

Percentage of filtering blebs with striping phenomenon. The percentage of filtering blebs with striping phenomenon in the three groups at postoperative 2 weeks (2 W), 1 month (1 M), 3 months (3 M), 6 months (6 M), 12 months (12 M), 18 months (18 M), 24 months (24 M). P < 0.05 was considered as statistically significant. Statistically significant between Phaco-ExPRESS vs. Phaco-Trab group, Phaco-Trab vs. Trab group, and Phaco-ExPRESS vs. Trab group were marked as †, ‡, and §, respectively. The Phaco-ExPRESS and the Trab group showed higher percentage of filtering blebs with striping phenomenon than the Phaco-Trab group from 3 months to 24 months postoperatively