Abstract
Purpose :
To describe the ultra-structural variations in surgical specimens of trabecular meshwork (TM) of primary and secondary glaucoma eyes using Scanning Electron Microscopy (SEM)
Methods :
Twenty-five glaucoma patients (n = Visual field mean deviation -6 to –12 dB = 3 eyes, <-12 dB = 22 eyes, Primary angle closure glaucoma [PACG] - 11, Primary open angle glaucoma [PACG] - 9 and Secondary glaucoma [SG] - 5) underwent glaucoma procedures (Trabeculectomy - 23, Kahook’s Dual blade goniotomy – 2). 1.5 x 1 mm TM specimens from trabeculectomy and strips from Goniotomy procedures were subjected to high vacuum SEM after securing the TM surface (subsequent to gold nanolayering, x400 to x3000 magnification) and TM topology were assessed by independent observers comparing normal TM samples.
Results :
Majority eyes had advanced glaucoma (n=20/25 eyes). All the TM specimens had fused trabecular beams, TM surface irregularities with complete disruption of normal TM architecture and powdery deposits filling inter trabecular gaps. Few inter trabecular voids were seen in POAG eyes while PACG and SG eyes had completely fused beams with more powdery deposits (2/11 vs13/14 eyes, p=0.0002, Fisher’s exact test). Thicker trabecular beams (Axenfeld-Rieger anomaly), excess pigments or deposits (pigmentary or pseudoexfoliation glaucomas) and red blood cells in between fused TM beams (angle recession glaucoma) were noted in SG eyes.
Conclusions :
This largest series of SEM-TM topology analysis in advanced glaucomas showed subtle but distinct ultra-structural variations that differentiated primary and secondary glaucomas. PACG and SG eyes showed more severe changes compared to POAG eyes. Further analysis of TM surgical specimens at varying stages of glaucoma can provide clues into the pathological course of different glaucoma types.
This abstract was presented at the 2024 ARVO Imaging in the Eye Conference, held in Seattle, WA, May 4, 2024.