Confocal Microscopy of Filtering Blebs after Trabeculectomy

Area of Science:

• Ophthalmology
• Surgical Innovation
• Medical Imaging

Background:

• Glaucoma surgery aims to lower intraocular pressure (IOP) by facilitating aqueous humor drainage.
• Filtration bleb (FB) formation and conjunctival scarring are critical to surgical success.
• FB morphology often doesn't correlate with IOP, and reasons for trabeculectomy failure are unclear.

Purpose of the Study:

• To assess filtering bleb morphology and function post-trabeculectomy using in vivo confocal microscopy.
• To investigate the influence of implant type and surgical timing on bleb characteristics.
• To correlate microstructural features with functional outcomes in glaucoma patients.

Main Methods:

• In vivo confocal microscopy (CFM) examined 46 eyes of 33 glaucoma patients (POAG, pseudoexfoliative, juvenile).
• Trabeculectomy with Mitomycin C was performed; implants (Express, Ologen) were used in some cases.
• FB structure was analyzed based on epithelium, stroma (collagen mesh), and vascularization over 1-22 years.

Main Results:

• FB function correlated significantly with collagen mesh (fine/dense) and vascularization (p=0.009).
• Functioning blebs showed fine collagen and less tortuous vessels (Stage 1), while non-functioning blebs had dense collagen and severe vascularization (p<0.05).
• Implant type affected vessel tortuosity (p=0.026), with Express showing less tortuosity than Ologen or no implant.

Conclusions:

• In vivo confocal microscopy offers novel cellular-level insights into FB healing processes.
• Microstructural analysis of FBs can help predict surgical outcomes in glaucoma.
• CFM is a valuable tool for understanding the dynamic changes influencing filtration bleb function.