First results of channel dilation in non-penetrating surgery for primary open-angle glaucoma

The surgery of Schlemm's canal is related to microinvasive surgery for primary open-angle glaucoma, which is why this area in ophthalmology is rapidly advancing and is a priority. The goal is to develop a technique for canal dilation performed during non-penetrating deep sclerectomy, as well as to assess its impact on the condition of Schlemm's canal and the hydrodynamic parameters of the eye. Materials and methods: This paper presents an analysis of the results of non-penetrating surgery with Schlemm's canal dilation in 30 patients (30 eyes) with advanced primary open-angle glaucoma (main group) compared to standard technology for minimally invasive non-penetrating surgery (30 patients, 30 eyes). All patients underwent ophthalmoscopy, biomicroscopy, keratorefractometry, computer perimetry, tonometry, tonography, gonioscopy, pachymetry, optical coherence tomography of the optic nerve head and anterior segment with measurement of the longitudinal and transverse axis diameters, as well as the area of sagittal scanning of Schlemm's canal. Results and discussion: The hypotensive effect after surgery was more pronounced in the main group of patients at 45.3 %, compared to 39.3 % in the control group (p 0.05). The hypotensive effect in the main group was due to a significantly greater outflow of intraocular fluid. The difference between the mean values of the outflow facility coefficient of intraocular fluid in the main group, (0.3 ± 0.05) mm³/mm Hg × min, and the control group, (0.24 ± 0.04) mm³/mm Hg × min, was statistically significant (p 0.001). Six months after surgery, the average area of Schlemm's canal was 41.7 % larger than that of the control group patients. The difference between the mean values of the area of Schlemm's canal in the main group, (1996.7 ± 232.4) µm², and the control group (1163.4 ± 226.9) µm², was statistically significant (p 0.001). Conclusion: Canal dilation during non-penetrating glaucoma surgery allows for the safe elimination of Schlemm's canal collapse, significantly expanding its lumen, normalizing intraocular hydrodynamics, and contributing to the stabilization of visual functions.