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Anterior Segment OCT Imaging of Bleb Morphological Changes as Predictors of Success After Bleb Needling
Abdülcemal Gürpınar1, Nurşen Arıtürk2
1Ordu State Hospital, Clinic of Ophthalmology, Ordu, Türkiye.
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.
