Clinical analysis of trabeculectomy filtering bleb vascularization parameters based on tomographic images using machine vision methods

The shape of the filtration bleb (FB) largely determines the hypotensive effect of glaucoma surgery. Purpose: to conduct a clinical analysis of the vascularization parameters of FB after trabeculectomy based on tomographic images using machine vision techniques. Material and methods. 83 patients (100 eyes) aged 57 to 81 years with moderate and advanced primary open-angle glaucoma underwent trabeculectomy using the standard technique. Biomicroscopic photography and optical coherence tomography with angiography of the filtration zone were performed preoperatively and at 1, 2, and 6 weeks postoperatively. IOP levels were monitored using a contactless pneumotonometer. Vascular network density, vascular tortuosity, and the degree of hyperemia were assessed using the tomographic image of the surgical area. Results. All assessed FB parameters increased to varying degrees by 1 week postoperatively, with a tendency to normalize by 6 weeks. Vascular density and the degree of superficial hyperemia experienced the greatest changes. A high correlation was observed between vascular density and hyperemia at all follow-up periods, as well as a significant correlation between postoperative IOP and vascular density beginning in the 2nd week of follow-up, with a tendency toward increased strength by 6 weeks. Conclusion. The development of a combined software method for determining the degree of vascularization and tortuosity of the FB vascular network, as well as hyperemia, using tomographic images and machine vision techniques can serve as a basis for assessing the effectiveness of glaucoma surgical treatment.

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