Anterior Segment OCT Imaging of Bleb Morphological Changes as Predictors of Success After Bleb Needling.

OBJECTIVES

To determine the bleb morphology and anterior segment changes after needling in trabeculectomy patients with filtration failure by anterior segment-optical coherence tomography (AS-OCT), and to identify morphological predictors of success.

MATERIALS AND

METHODS

Thirty-two eyes of 32 patients who underwent trabeculectomy with mitomycin C and experienced filtration failure underwent bleb needling with subconjunctival 5-fluorouracil injection. AS-OCT imaging was performed before and at several time points up to 6 months post-needling. Intraocular pressure (IOP), anterior chamber depth, and bleb height and width were measured. Complete success was defined as achieving IOP ≤19 mmHg without medication, and qualified success as IOP ≤19 mmHg with medication at 6 months.

RESULTS

The mean age of the patients was 61.7±7.8 years (range, 44-76), and the mean interval between trabeculectomy and needling was 6.6±6.1 months (range, 1-26). IOP was 27.70±5.11 mmHg preoperatively (preop), 18.32±7.51 mmHg at 1 month, and 20.90±7.03 mmHg at 6 months. The decrease in IOP was statistically significant (p=0.015 and p=0.397, respectively). Bleb width was 3.74±0.67 mm preop, 4.16±0.55 mm at 1 month, and 3.9±0.49 mm at 6 months (p=0.001 and p=0.047, respectively). Bleb height was 0.45±0.16 mm preop, 0.41±0.11 mm at 1 month, and 0.40±0.11 mm at 6 months (p=0.812 and p=0.249, respectively). The success rate of needling was 75% at 1 month and 40.6% at 6 months. There were significant differences in age, preop IOP, and bleb height after needling between indistinct and encapsulated blebs. Choroidal effusion developed in 3 patients and resolved with medical treatment. Ahmed glaucoma valve implantation was performed in 6 patients who could not reach the target IOP.

CONCLUSION

AS-OCT imaging provides an objective and reproducible evaluation of bleb morphological changes after needling. Reduced bleb height, particularly in encapsulated blebs, and increased microcyst density observed on AS-OCT predict successful aqueous humor drainage. Incorporating AS-OCT assessments into clinical practice could improve postoperative management by enabling early detection of bleb dysfunction and guiding timely interventions.