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Abstract #109651 Published in IGR 24-1
Greater Outflow Facility Increase After Targeted Trabecular Bypass in Angiographically Determined Low-flow Regions
Strohmaier CA; Wanderer D; Zhang X; Agarwal D; Toomey CB; Wahlin K; Zhang HF; Stamer WD; Weinreb RN; McDonnell FS; Huang ASOphthalmology. Glaucoma 2023; 6: 570-579
PURPOSE: To investigate the impact of trabecular bypass surgery targeted to angiographically determined high- vs. low-aqueous humor outflow areas on outflow facility (C) and intraocular pressure (IOP). DESIGN: Ex vivo comparative study. SUBJECTS: Postmortem ex vivo porcine and human eyes. METHODS: Porcine (n = 14) and human (n = 13) whole globes were acquired. In both species, anterior segments were dissected, mounted onto a perfusion chamber, and perfused using Dulbecco's phosphate buffered solution containing glucose in a constant flow paradigm to achieve a stable baseline. Fluorescein was perfused into the anterior chamber and used to identify baseline segmental high- and low-flow regions of the conventional outflow pathways. The anterior segments were divided into 2 groups, and a 5 mm needle goniotomy was performed in either a high- or low-flow area. Subsequently, C and IOP were quantitatively reassessed and compared between surgery in baseline "high-flow" and "low-flow" region eyes followed by indocyanine green angiography. MAIN OUTCOME MEASURES: Outflow facility. RESULTS: In all eyes, high- and low-flow segments could be identified. Performing a 5-mm goniotomy increased outflow facility to a variable extent depending on baseline flow status. In the porcine high-flow group, C increased from 0.31 ± 0.09 to 0.39 ± 0.09 μL/mmHg/min (P = 0.12). In the porcine low-flow group, C increased from 0.29 ± 0.03 to 0.56 ± 0.10 μL/mmHg/min (P < 0.001). In the human high-flow group, C increased from 0.38 ± 0.20 to 0.41 ± 0.20 μL/mmHg/min (P = 0.02). In the human low-flow group, C increased from 0.25 ± 0.11 to 0.32 ± 0.11 μL/mmHg/min (<0.001). There was statistically significant greater increase in C for eyes where surgery was targeted to baseline low-flow regions in both porcine (0.07 ± 0.09 vs. 0.27 ± 0.13, P = 0.007 μL/mmHg/min, high vs low flow) and human eyes (0.03 ± 0.03 vs. 0.07 ± 0.02, P = 0.03 μL/mmHg/min, high vs. low flow). CONCLUSIONS: Targeting surgery to low-flow areas of the trabecular meshwork yields higher overall facility increase and IOP reduction compared to surgery in high-flow areas. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.
Department of Ophthalmology and Optometry, Kepler University Hospital, Johannes Kepler University, Linz, Austria; The Viterbi Family Department of Ophthalmology, Hamilton Glaucoma Center, Shiley Eye Institute, University of California, San Diego, California. Electronic address: Clemens.strohmaier@gmail.com.
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