Purpose: To investigate the spectral content of intraocular pressure (IOP) pulse wave by advanced spectral signal processing of continuous IOP readings obtained by dynamic contour tonometry.
Patients and methods: A non-interventional case-control study included 20 healthy subjects, 20 previously untreated primary open angle glaucoma patients, and 20 previously untreated normal tension glaucoma patients. The continuous IOP reading obtained by dynamic contour tonometry was submitted to Fast Fourier Transform signal analysis and further statistical data processing.
Results: The spectral components of the IOP pulse wave were discerned up to the fifth harmonic. Highly statistically significant difference was found between the control group and the primary open angle group, and between the primary open angle glaucoma group and the normal tension glaucoma group in the first, second and the third harmonic amplitude (p < 0.01). Glaucoma patients had significantly higher ocular pulse volume values.
Conclusions: It is possible to determine spectral components of the IOP pulse wave up to the fifth harmonic by a spectral analysis of dynamic contour tonometry continuous readings. We found that high Ocular Pulse Amplitude values in primary open angle glaucoma group was associated with high harmonics amplitude, which indicates low rigidity of blood vessels.