Bleb-related Porcine Lymphatic Outflow is Greater from Subconjunctival compared to Subtenon Blebs

Jong Yeon Lee; Clemens Adolf Strohmaier; Goichi Akiyama; Sindhu Saraswathy; Chungkwon Yoo; Yong Yeon Kim; Young-Kwon Hong; Alex S Huang

doi:10.5005/jp-journals-10078-1382

Bleb-related Porcine Lymphatic Outflow is Greater from Subconjunctival compared to Subtenon Blebs

J Curr Glaucoma Pract. 2022 Sep-Dec;16(3):144-151. doi: 10.5005/jp-journals-10078-1382.

Authors

Jong Yeon Lee¹, Clemens Adolf Strohmaier², Goichi Akiyama³, Sindhu Saraswathy⁴, Chungkwon Yoo⁵, Yong Yeon Kim⁵, Young-Kwon Hong⁶, Alex S Huang⁷

Affiliations

¹ Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, California, USA; Department of Ophthalmology, Gachon University College of Medicine, Gil Medical Center, Incheon, Korea.
² Department of Ophthalmology, Johannes Kepler University, Linz, Austria; The Viterbi Family Department of Ophthalmology, Shiley Eye Institute, Hamilton Glaucoma Center, University of California, San Diego, California.
³ Jikei School of Medicine, Tokyo, Japan.
⁴ Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, California, USA.
⁵ Department of Ophthalmology, Korea University College of Medicine, Seoul, Korea.
⁶ Department of Surgery, Norris Comprehensive Cancer Center Keck School of Medicine, University of Southern California, Los Angeles, California, USA.
⁷ Alfred Vogt Endowed Chair in Ophthalmology, The Viterbi Family Department of Ophthalmology, Shiley Eye Institute, Hamilton Glaucoma Center, University of California, San Diego, California, USA.

Abstract

Aim: Understanding the mechanism of fluid outflow by comparing the subconjunctival and subtenon spaces can lead to improved ocular therapeutics. The purpose of the current study is to evaluate subconjunctival vs subtenon lymphatic outflow by creating tracer-filled blebs in each location.

Methods: Porcine (n = 20) eyes received subconjunctival or subtenon injection(s) of fixable and fluorescent dextrans. Blebs were angiographically imaged using a Heidelberg Spectralis ([Heidelberg Retina Angiograph] HRA + OCT; Heidelberg Engineering) and bleb-related lymphatic outflow pathways were counted. Optical coherence tomography (OCT) imaging of these pathways was used to assess structural lumens and the presence of valve-like structures. Furthermore, a comparison between tracer injection locations (superior/inferior/temporal/nasal) was made. Histologic analyses for subconjunctival and subtenon outflow pathways were performed, to confirm tracer co-localization with molecular lymphatic markers.

Results: Subconjunctival blebs demonstrated a greater number of lymphatic outflow pathways compared to subtenon blebs in every quadrant [superior: 6.10 ± 1.18 (subconjunctival) vs 0.50 ± 0.27 (subtenon); temporal: 2.30 ± 0.40 vs 0.10 ± 0.10; nasal: 5.30 ± 0.60 vs 0.30 ± 0.21; inferior: 6.00 ±1.29 vs 0.1 ± 0.1; all comparisons p < 0.001]. For subconjunctival blebs, the temporal quadrant showed fewer lymphatic outflow pathways compared to the nasal side (p = 0.005).

Discussion: Subconjunctival blebs accessed greater lymphatic outflow compared to subtenon blebs. Furthermore, regional differences existed, with fewer lymphatic vessels temporal than at the other locations.

Clinical significance: Aqueous humor drainage after glaucoma surgery is incompletely understood. The present manuscript adds to our understanding of how lymphatics might influence filtration bleb function.

How to cite this article: Lee JY, Strohmaier CA, Akiyama G, et al. Bleb-related Porcine Lymphatic Outflow Is Greater from Subconjunctival compared to Subtenon Blebs. J Curr Glaucoma Pract 2022;16(3):144-151.

Keywords: Aqueous outflow; Blebs; Conjunctiva; Glaucoma surgery; Laboratory research; Lymphatics; Subconjunctival; Subtenon.

Abstract

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