Related Experiment Video
Updated: Jul 9, 2026
High-resolution Confocal Imaging of the Blood-brain Barrier: Imaging, 3D Reconstruction, and Quantification of Transcytosis
Published on: November 16, 2017
Filtering blebs and aqueous pathway an immunocytological and in vivo confocal microscopy study
Nawel Amar1, Antoine Labbé, Pascale Hamard
1Department of Ophthalmology III, Quinze-Vingts National Ophthalmology Hospital, Paris, France.
Insights
Filtering surgery blebs were studied using advanced microscopy. Functioning blebs show microcysts, potentially indicating an aqueous humor transcellular pathway through goblet cells.
Area of Science:
- Ophthalmology
- Cell Biology
- Surgical Science
Background:
- Filtering surgery, like trabeculectomy, aims to reduce intraocular pressure.
- Understanding aqueous humor dynamics post-surgery is crucial for optimizing outcomes.
- Cellular-level characterization of filtering blebs is limited.
Purpose of the Study:
- To elucidate aqueous humor pathways at the cellular level after filtering surgery.
- To characterize the cellular changes in functioning versus non-functioning filtering blebs.
- To utilize in vivo confocal microscopy and impression cytology for bleb analysis.
Main Methods:
- Observational case series of 29 patients (32 blebs) post-trabeculectomy.
- In vivo confocal microscopy and impression cytology (IC) were employed.
- Analysis included goblet cell and inflammatory cell immunostaining, with eyes classified into functioning, non-functioning, and post-mitomycin C groups.
Main Results:
- Non-functioning blebs had few MUC5AC-positive cells on their surface.
- Functioning blebs exhibited numerous goblet cells and intraepithelial microcysts.
- Inflammatory cells were present in all blebs, particularly after mitomycin C treatment.
Conclusions:
- Impression cytology and in vivo confocal microscopy offer novel insights into filtering blebs.
- Microcysts in functioning blebs may represent goblet cells channeling aqueous humor.
- A transcellular pathway for aqueous humor via goblet cells towards the ocular surface is hypothesized.
Objective:
To characterize and understand, at the cellular level, the aqueous humor pathways after filtering surgery, using in vivo confocal microscopy and impression cytology (IC).
Design:
Observational case series.
Participants:
Thirty-two blebs of 29 patients after trabeculectomy were retrospectively evaluated.
Methods:
In vivo confocal microscopy and immunofluorescence staining of IC samples taken on and around the bleb area were performed. Impression cytology samples were examined under confocal microscopy after goblet cell and inflammatory cell immunostaining with anti-MUC5AC and antivimentin antibodies, respectively. Eyes were classified into 3 groups: (1) functioning blebs (11 eyes), (2) nonfunctioning blebs (10 eyes), and (3) functioning blebs after mitomycin C application (12 eyes). Impression cytology specimens and in vivo confocal microscopy images were analyzed and compared in a masked manner.
Main Outcome Measures:
Conjunctival epithelium changes of each type of bleb were analyzed using both impression cytology specimens and in vivo confocal microscopy and correlated to clinical outcomes.
Results:
In all IC specimens, numerous MUC5AC-positive cells were observed outside the edges of the blebs. Few MUC5AC-positive cells were observed at the surface of nonfunctioning blebs. Numerous goblet cells with immunostaining that was weak or limited to the membrane were clearly visible morphologically at the surface of functioning blebs (with and without adjunctive mitomycin C). Using in vivo confocal microscopy, all functioning blebs showed numerous intraepithelial optically empty microcysts, whereas nonfunctioning blebs had none or only a few. All blebs contained dendritiform inflammatory cells, especially after mitomycin C application.
Conclusion:
Impression cytology and in vivo confocal microscopy provide a new approach to filtering blebs. Microcysts observed at the surface of functioning blebs seemed to correspond to goblet cells, mostly containing aqueous humor instead of highly hydrophilic gel-forming mucins. Although this hypothesis requires further confirmation, the transcellular pathway of the aqueous humor could be hypothesized to occur at the level of goblet cells toward the ocular surface.
