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PURPOSE: To ascertain whether changes in the spectral content of the corneal pulse (CP) signal, measured in vivo in primary open-angle glaucoma (POAG) patients, indirectly reflect changes in corneal biomechanics after canaloplasty. METHODS: Fifteen eyes of 15 POAG patients who underwent canaloplasty combined with phacoemulsification were enrolled. Standard ophthalmic examinations were conducted before washout, pre-operatively, at days 1, 7, and 1, 3, 6, and 12 months after surgery. Non-contact measurements of the CP signal were performed at pre-washout, pre-operatively, and at 3, 6, and 12 months post-operatively. Then, amplitudes of the CP first five harmonics associated with the heart rate were estimated. Temporal changes of all considered parameters were tested at a Bonferroni-adjusted significance level set to 0.005. RESULTS: A decrease in the amplitude of the first harmonic and an increase in the normalized amplitude of the third harmonic (A) of the CP signal were noticed between the pre-washout and the pre-operative stages (p = 0.003 and p = 0.004, respectively). This corresponds to an increase in median intraocular pressure (IOP) values by 6.0 mmHg (p = 0.0045). After surgery, A reached the highest value at 3 months post-operatively, compared with pre-washout level (p = 0.0045). CONCLUSIONS: Alterations in corneoscleral stiffness caused by surgery are reflected in changes in the A value. Hence, post-operative corneal biomechanics could be monitored indirectly by this supporting indicator that can be used to estimate the time at which measures of IOP are no longer biased by the changed cornea boundary conditions caused by canaloplasty. CLINICAL TRIALS REGISTRATION: NCT02908633.
Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370, Wrocław, Poland. monika.danielewska@pwr.edu.pl.
Full article12.8.3 Non-perforating (Part of: 12 Surgical treatment > 12.8 Filtering surgery)
12.14.3 Phacoemulsification (Part of: 12 Surgical treatment > 12.14 Combined cataract extraction and glaucoma surgery)
2.2 Cornea (Part of: 2 Anatomical structures in glaucoma)
6.11 Bloodflow measurements (Part of: 6 Clinical examination methods)