Abstract

Aim To investigate the relationship between intrascleral bleb height and intraocular pressure (IOP) following deep sclerectomy with collagen implant (DSCI) and mitomycin C (MMC) in eyes with clinically flat blebs.

Methods The records of 25 eyes of 22 consecutive patients presenting with clinically flat blebs following DSCI with MMC for primary or secondary open angle glaucoma were reviewed. Anterior segment optical coherence tomography (AS-OCT) scans were used to evaluate postoperative intrascleral bleb height and its relation to IOP control. Eyes requiring postoperative bleb manipulations, needling or goniopunctures were excluded.

Results The mean age of the patients was 71.9±12.6 years, and the mean preoperative IOP was 25.3±5.6 mm Hg. The mean time of the AS-OCT examination from the operation was 8±4.9 months, and the mean IOP at that time was 13.8±4.2 mm Hg (p<0.001). All operated eyes manifested an intrascleral bleb with AS-OCT. The mean intrascleral bleb height was 0.58±0.16 mm. IOP and intrascleral bleb height were found to be inversely correlated (p<0.001, r=−0.626). None of the eyes had subconjuctival blebs, and 17/25 eyes showed microscopic conjuctival fluid collections.

Conclusion The authors report a positive inverse correlation between intrascleral bleb height and postoperative IOP in eyes presenting clinically flat blebs following DSCI with MMC, suggesting an important role for intrascleral filtration in lowering IOP. Further studies are warranted to evaluate this relationship at different postoperative time points and possibly with different types of implants.