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Park YJ, Lee JM, Choi KH. Harmonic components of photoplethysmography and pathological patterns: A cross-sectional study. Medicine (Baltimore) 2023; 102:e34200. [PMID: 37657055 PMCID: PMC10476820 DOI: 10.1097/md.0000000000034200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 06/14/2023] [Indexed: 09/03/2023] Open
Abstract
This study aimed to examine whether the 3 harmonic components (HCs) of photoplethysmography (PTG) - total harmonic distortion (THD), harmonic power (HP), and normalized harmonic amplitude (HA) - have aging effects and may serve as an arterial stiffness marker and examine the relationship between HCs and clinical severity of pathological patterns. This study had a retrospective chart review design, and electronic medical records of 173 female patients (age: 38.57 ± 11.64 years) were reviewed. Patients were asked to complete the phlegm, blood stasis (BS), and food retention (FR) pattern questionnaires and underwent PTG and the second derivative of PTG measurements. THD, HP, and HA data were extracted till the 12th HCs from the raw PTG data. THD and HA had an aging effect (β: -0.179 to -0.278) and were related to b/a (r: -02.76 to -0.455) and d/a (r: 0.265-0.360) of the second derivative of PTG. In the younger group (≤33 years), HP and HA were positively correlated with phlegm, BS, and FR patterns (r: 0.257-0.370), while HP was positively correlated with the FR pattern (r: 0.278-0.315) in the middle age group (34-45 years). In the older group (≥46 years), HP and HA were positively or negatively correlated with the phlegm pattern (r: ±0.263 to ±0.440). HCs may serve as an arterial stiffness marker, and may be partially related to phlegm, BS, and FR patterns. Aging effect needs to be considered when utilizing HCs as an indicator of phlegm, BS, and FR patterns.
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Affiliation(s)
- Young-Jae Park
- Department of Biofunctional Medicine and Diagnostics, College of Korean Medicine, Kyung Hee University, Seoul, Republic of Korea
- Department of Diagnosis and Biofunctional Medicine, Kyung Hee University Hospital at Gangdong, Seoul, Republic of Korea
- Department of Biofunctional Medicine and Diagnostics, Graduate School, College of Korean Medicine, Kyung Hee University, Seoul, Republic of Korea
| | - Jin-Moo Lee
- Department of Gynecology, College of Korean Medicine, Kyung Hee University, Seoul, Republic of Korea
- Department of Women Health Clinic, Kyung Hee University Hospital at Gangdong, Seoul, Republic of Korea
| | - Ka-Hye Choi
- Department of Biofunctional Medicine and Diagnostics, Graduate School, College of Korean Medicine, Kyung Hee University, Seoul, Republic of Korea
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Abdul-Rahman A, Morgan W, Jo Khoo Y, Lind C, Kermode A, Carroll W, Yu DY. Linear interactions between intraocular, intracranial pressure, and retinal vascular pulse amplitude in the fourier domain. PLoS One 2022; 17:e0270557. [PMID: 35763528 PMCID: PMC9239478 DOI: 10.1371/journal.pone.0270557] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 06/13/2022] [Indexed: 11/19/2022] Open
Abstract
Purpose To compare the retinal vascular pulsatile characteristics in subjects with normal (ICPn) and high (ICPh) intracranial pressure and quantify the interactions between intraocular pressure, intracranial pressure, and retinal vascular pulse amplitude in the Fourier domain. Materials and methods Twenty-one subjects were examined using modified photoplethysmography with simultaneous ophthalmodynamometry. A harmonic regression model was fitted to each pixel in the time-series, and used to quantify the retinal vascular pulse wave parameters including the harmonic regression wave amplitude (HRWa). The pulse wave attenuation was measured under different ranges of induced intraocular pressure (IOPi), as a function of distance along the vessel (VDist). Intracranial pressure (ICP) was measured using lumbar puncture. A linear mixed-effects model was used to estimate the correlations between the Yeo-Johnson transformed harmonic regression wave amplitude (HRWa-YJt) with the predictors (IOPi, VDist and ICP). A comparison of the model coefficients was done by calculating the weighted Beta (βx) coefficients. Results The median HRWa in the ICPn group was higher in the retinal veins (4.563, interquartile range (IQR) = 3.656) compared to the retinal arteries (3.475, IQR = 2.458), p<0.0001. In contrast, the ICPh group demonstrated a reduction in the median venous HRWa (3.655, IQR = 3.223) and an elevation in the median arterial HRWa (3.616, IQR = 2.715), p<0.0001. Interactions of the pulsation amplitude with ICP showed a significant disordinal interaction and the loss of a main effect of the Fourier sine coefficient (bn1) in the ICPh group, suggesting that this coefficient reflects the retinal vascular response to ICP wave. The linear mixed-effects model (LME) showed the decay in the venous (HRWa-YJt) was almost twice that in the retinal arteries (−0.067±0.002 compared to −0.028±0.0021 respectively, p<0.00001). The overall interaction models had a total explanatory power of (conditional R2) 38.7%, and 42% of which the fixed effects explained 8.8%, and 5.8% of the variance (marginal R2) for the venous and arterial models respectively. A comparison of the damping effect of VDist and ICP showed that ICP had less influence on pulse decay than distance in the retinal arteries (βICP = -0.21, se = ±0.017 compared to βVDist=-0.26, se = ±0.019), whereas the mean value was equal for the retinal veins (venous βVDist=-0.42, se = ±0.015, βICP = -0.42, se = ±0.019). Conclusion The retinal vascular pulsation characteristics in the ICPh group showed high retinal arterial and low venous pulsation amplitudes. Interactions between retinal vascular pulsation amplitude and ICP suggest that the Fourier sine coefficient bn1 reflects the retinal vascular response to the ICP wave. Although a matrix of regression lines showed high linear characteristics, the low model explanatory power precludes its use as a predictor of ICP. These results may guide future predictive modelling in non-invasive estimation of ICP using modified photoplethysmography.
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Affiliation(s)
- Anmar Abdul-Rahman
- Department of Ophthalmology, Counties Manukau District Health Board, Auckland, New Zealand
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Perth, Australia
- * E-mail:
| | - William Morgan
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Perth, Australia
- Lions Eye Institute, University of Western Australia, Perth, Australia
| | - Ying Jo Khoo
- Lions Eye Institute, University of Western Australia, Perth, Australia
- Royal Perth Hospital, Perth, Australia
| | - Christopher Lind
- Neurosurgical Service of Western Australia, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
- Department of Surgery, University of Western Australia, Crawley, Western Australia, Australia
| | - Allan Kermode
- Centre for Neuromuscular and Neurological Disorders, Perron Institute for Neurological and Translational Science, Sir Charles Gairdner Hospital Department of Neurology and Clinical Neurophysiology, Nedlands, Western Australia, Australia
- Institute for Immunology and Infectious Disease, Murdoch University Faculty of Health Sciences, Murdoch, Western Australia, Australia
| | - William Carroll
- Centre for Neuromuscular and Neurological Disorders, Perron Institute for Neurological and Translational Science, Sir Charles Gairdner Hospital Department of Neurology and Clinical Neurophysiology, Nedlands, Western Australia, Australia
| | - Dao-Yi Yu
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Perth, Australia
- Lions Eye Institute, University of Western Australia, Perth, Australia
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Danielewska ME, Placek MM, Kicińska AK, Rękas M. Using the entropy of the corneal pulse signal to distinguish healthy eyes from eyes affected by primary open-angle glaucoma. Physiol Meas 2020; 41:055011. [PMID: 32299068 DOI: 10.1088/1361-6579/ab89c8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE The purpose of this study was to evaluate whether the complexity of the corneal pulse (CP) signal can be used to differentiate patients with primary open-angle glaucoma (POAG) from healthy subjects. APPROACH The study sample consisted of 28 patients with POAG and a control, age-matched group of 30 subjects. After standard ophthalmic examination, the CP signal from a randomly selected eye of each participant was measured using non-contact ultrasonic micro-displacement measurement technology. After pre-processing, the complexity of the CP signal was estimated using refined composite multiscale fuzzy entropy (RCMFE) up to scale factor 50. The average RCMFE values were computed from three repeated measurements of the CP signals for each participant and each scale factor. MAIN RESULTS The complexity of the CP signal in glaucomatous eyes was higher than that observed in healthy ones. Also, RCMFE of the CP signal was found to differentiate (statistically significantly) between the two groups for scales in the range from 26 to 43. For these scales, the one for which the lowest p-value (t-test, p = 0.017) was obtained when comparing RCMFE between the two groups was selected as the optimal scale. Next, a receiver operating characteristic analysis for the optimal scale showed that the proposed approach of calculating the multiscale entropy of the CP signal has some potential to discriminate between patients with POAG and healthy controls (sensitivity, specificity and accuracy of 0.643, 0.700 and 0.672, respectively). SIGNIFICANCE In conclusion, RCMFE, as a complexity measure, may be considered an auxiliary indicator to support glaucoma diagnostics.
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Affiliation(s)
- Monika E Danielewska
- Department of Biomedical Engineering, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
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Danielewska ME, Kicińska AK, Placek MM, Lewczuk K, Rękas M. Changes in spectral parameters of corneal pulse following canaloplasty. Graefes Arch Clin Exp Ophthalmol 2019; 257:2449-2459. [PMID: 31377849 DOI: 10.1007/s00417-019-04433-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 07/09/2019] [Accepted: 07/23/2019] [Indexed: 10/26/2022] Open
Abstract
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 (ACP3n) 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, ACP3n 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 ACP3n 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.
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Affiliation(s)
- Monika E Danielewska
- Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370, Wrocław, Poland.
| | - Aleksandra K Kicińska
- Department of Ophthalmology, Military Institute of Medicine, ul. Szaserów 128, 04-141, Warsaw, Poland
| | - Michał M Placek
- Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370, Wrocław, Poland
| | - Katarzyna Lewczuk
- Department of Ophthalmology, Military Institute of Medicine, ul. Szaserów 128, 04-141, Warsaw, Poland
| | - Marek Rękas
- Department of Ophthalmology, Military Institute of Medicine, ul. Szaserów 128, 04-141, Warsaw, Poland
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Danielewska ME, Messner A, Werkmeister RM, Placek MM, Aranha Dos Santos V, Rękas M, Schmetterer L. Relationship Between the Parameters of Corneal and Fundus Pulse Signals Acquired With a Combined Ultrasound and Laser Interferometry Technique. Transl Vis Sci Technol 2019; 8:15. [PMID: 31388467 PMCID: PMC6675519 DOI: 10.1167/tvst.8.4.15] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2019] [Accepted: 06/10/2019] [Indexed: 01/16/2023] Open
Abstract
Purpose To estimate the relationship between the characteristics of the corneal pulse (CP) signal and those of the fundus pulse (FP) signal measured with a combined noncontact ultrasonic and laser interferometry technique in healthy subjects. Methods Twenty-two healthy subjects participated in experiments that included measurements of intraocular pressure, ocular pulse amplitude, ocular biometry, blood pressure, and heart rate. Additionally, simultaneous recordings of CP and FP signals were acquired with a noncontact ultrasonic device combined with laser interferometry. Subsequently, ocular perfusion pressure (OPP) and the time and spectral parameters of CP and FP signals were computed. A system model was proposed to relate the FP signal to the CP signal. Results The system model revealed that the eye globe transfers information between signals of the posterior and anterior eye, relatively amplifying higher spectral harmonics. The amplitude of the second CP harmonic is predicted by FPRMS and OPP (R2 = 0.468, P = 0.002). Partial correlation analysis showed that the CP signal parameters are statistically significantly correlated with those of the FP signal and OPP, after correcting for age and sex. Conclusions The eye globe can be viewed as a high pass filter, in which the CP characteristic changes in relation to the fundus pulsation. The FP signal and OPP have an impact on the variations of the CP signal morphology. Translational Relevance Investigation of differences between the characteristics of the anterior and posterior tissue movements is a promising method for evaluating the role of circulatory and biomechanical components in the pathophysiology of ocular diseases.
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Affiliation(s)
- Monika E Danielewska
- Wrocław University of Science and Technology, Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wrocław, Poland
| | - Alina Messner
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - René M Werkmeister
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Michał M Placek
- Wrocław University of Science and Technology, Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wrocław, Poland
| | | | - Marek Rękas
- Department of Ophthalmology, Military Institute of Medicine, Warsaw, Poland
| | - Leopold Schmetterer
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,Singapore Eye Research Institute, Singapore National Eye Centre, Singapore.,Academic Clinical Program, Duke-NUS Medical School, Singapore.,Department of Ophthalmology, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.,Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
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Rogala MM, Danielewska ME, Antończyk A, Kiełbowicz Z, Rogowska ME, Kozuń M, Detyna J, Iskander DR. In-vivo corneal pulsation in relation to in-vivo intraocular pressure and corneal biomechanics assessed in-vitro. An animal pilot study. Exp Eye Res 2017; 162:27-36. [PMID: 28689748 DOI: 10.1016/j.exer.2017.07.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2016] [Revised: 06/30/2017] [Accepted: 07/05/2017] [Indexed: 01/27/2023]
Abstract
The aim was to ascertain whether the characteristics of the corneal pulse (CP) measured in-vivo in a rabbit eye change after short-term artificial increase of intraocular pressure (IOP) and whether they correlate with corneal biomechanics assessed in-vitro. Eight New Zealand white rabbits were included in this study and were anesthetized. In-vivo experiments included simultaneous measurements of the CP signal, registered with a non-contact method, IOP, intra-arterial blood pressure, and blood pulse (BPL), at the baseline and short-term elevated IOP. Afterwards, thickness of post-mortem corneas was determined and then uniaxial tensile tests were conducted leading to estimates of their Young's modulus (E). At the baseline IOP, backward stepwise regression analyses were performed in which successively the ocular biomechanical, biometric and cardiovascular predictors were separately taken into account. Results of the analysis revealed that the 3rd CP harmonic can be statistically significantly predicted by E and central corneal thickness (Models: R2 = 0.662, p < 0.005 and R2 = 0.832, p < 0.001 for the signal amplitude and power, respectively). The 1st CP harmonic can be statistically significantly predicted by the amplitude and power of the 1st BPL harmonic (Models: R2 = 0.534, p = 0.015 and R2 = 0.509, p < 0.018, respectively). For elevated IOP, non-parametric analysis indicated significant differences for the power of the 1st CP harmonic (Kruskal-Wallis test; p = 0.031) and for the mean, systolic and diastolic blood pressures (p = 0.025, p = 0.019, p = 0.033, respectively). In conclusion, for the first time, the association between parameters of the CP signal in-vivo and corneal biomechanics in-vitro was confirmed. In particular, spectral analysis revealed that higher amplitude and power of the 3rd CP harmonic indicates higher corneal stiffness, while the 1st CP harmonic correlates positively with the corresponding harmonic of the BPL signal.
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Affiliation(s)
- Maja M Rogala
- Wroclaw University of Science and Technology, Department of Mechanics, Materials Science and Engineering, Faculty of Mechanical Engineering, ul. Smoluchowskiego 25, 50-370 Wroclaw, Poland.
| | - Monika E Danielewska
- Wroclaw University of Science and Technology, Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland.
| | - Agnieszka Antończyk
- Wroclaw University of Environmental and Life Sciences, Department of Surgery, Faculty of Veterinary Medicine, pl. Grunwaldzki 51, 50-366 Wroclaw, Poland.
| | - Zdzisław Kiełbowicz
- Wroclaw University of Environmental and Life Sciences, Department of Surgery, Faculty of Veterinary Medicine, pl. Grunwaldzki 51, 50-366 Wroclaw, Poland.
| | - Marta E Rogowska
- Wroclaw University of Science and Technology, Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland.
| | - Marta Kozuń
- Wroclaw University of Science and Technology, Department of Biomedical Engineering, Mechatronics and Theory of Mechanisms, Faculty of Mechanical Engineering, ul. Lukasiewicza 7/9, 50-371 Wroclaw, Poland.
| | - Jerzy Detyna
- Wroclaw University of Science and Technology, Department of Mechanics, Materials Science and Engineering, Faculty of Mechanical Engineering, ul. Smoluchowskiego 25, 50-370 Wroclaw, Poland.
| | - D Robert Iskander
- Wroclaw University of Science and Technology, Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland.
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Tejwani S, Dinakaran S, Joshi A, Shetty R, Sinha Roy A. A cross-sectional study to compare intraocular pressure measurement by sequential use of Goldman applanation tonometry, dynamic contour tonometry, ocular response analyzer, and Corvis ST. Indian J Ophthalmol 2016; 63:815-20. [PMID: 26669331 PMCID: PMC4730691 DOI: 10.4103/0301-4738.171956] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
OBJECTIVE To study the correlation and effect of sequential measurement of intraocular pressure (IOP) with Goldmann applanation tonometer (GAT), ocular response analyzer (ORA), dynamic contour tonometer (DCT), and Corvis ST. SETTING AND DESIGN Observational cross-sectional series from the comprehensive clinic of a tertiary eye care center seen during December 2012. METHODS One hundred and twenty-five study eyes of 125 patients with normal IOP and biomechanical properties underwent IOP measurement on GAT, DCT, ORA, and Corvis ST; in four different sequences. Patients with high refractive errors, recent surgeries, glaucoma, and corneal disorders were excluded so as to rule out patients with evident altered corneal biomechanics. STATISTICAL ANALYSIS Linear regression and Bland-Altman using MedCalc software. RESULTS Multivariate analysis of variance with repeated measures showed no influence of sequence of device use on IOP (P = 0.85). Linear regression r2 between GAT and Corvis ST, Corvis ST and Goldmann-correlated IOP (IOPg), and DCT and Corvis ST were 0.37 (P = 0.675), 0.63 (P = 0.607), and 0.19 (P = 0.708), respectively. The Bland-Altman agreement of Corvis ST with GAT, corneal compensated IOP, and IOPg was 2 mmHg (-5.0 to + 10.3), -0.5 mmHg (-8.1 to 7.1), and 0.5 mmHg (-6.2 to 7.1), respectively. Intraclass correlation coefficient for repeatability ranged from 0.81 to 0.96. CONCLUSIONS Correlation between Corvis ST and ORA was found to be good and not so with GAT. However, agreement between the devices was statistically insignificant, and no influence of sequence was observed.
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Affiliation(s)
- Sushma Tejwani
- Department of Glaucoma, Narayana Nethralaya, Bengaluru, Karnataka, India
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Bozic MM, Dukic ML, Stojkovic MZ. Spectral analysis of intraocular pressure pulse wave in ocular hypertensive and primary open angle glaucoma patients. Indian J Ophthalmol 2016; 64:114-7. [PMID: 27050344 PMCID: PMC4850804 DOI: 10.4103/0301-4738.179719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Context: In attempt to find an alternative way to determine conversion from ocular hypertension to primary open angle glaucoma (POAG) (besides visual field and optic disc changes), we analyzed intraocular pressure (IOP) pulse wave in spectral domain. Aims: The aim of this study was to test the potential differences in spectral content of IOP pulse wave between ocular hypertension and POAG patients, which could indicate conversion. Settings and Design: Cross-sectional study designed to test the differences in the spectral content of pressure pulse wave between nontreated ocular hypertensive and nontreated, freshly diagnosed POAG patients. Methods: The total of 40 eyes of 40 subjects was included: 20 previously untreated ocular hypertensive patients, and 20 previously untreated POAG patients. Continuous IOP measuring gained by dynamic contour tonometry was submitted to fast Fourier transform signal analysis and further statistical data processing. Statistics Analysis Used: Ocular and systemic characteristics of the tested subjects were compared by analysis of variance appropriate for this study design. A P < 0.05 was considered to be statistically significant. Results: Higher spectral components of the IOP pulse wave was discerned up to the fifth harmonic in both of the tested groups. No statistically significant differences were found in any of the tested harmonic amplitudes. Conclusions: There are no differences in the spectral content of IOP pulse wave between ocular hypertensive and primary open angle glaucoma patients which could be indicative for conversion.
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Affiliation(s)
- Marija M Bozic
- Department of Glaucoma, Faculty of Medicine, University of Belgrade, Belgrade; Clinic of Ophthalmology, Clinical Center of Serbia, Belgrade, Serbia
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Tejwani S, Shetty R, Kurien M, Dinakaran S, Ghosh A, Roy AS. Biomechanics of the cornea evaluated by spectral analysis of waveforms from ocular response analyzer and Corvis-ST. PLoS One 2014; 9:e97591. [PMID: 25162229 PMCID: PMC4146464 DOI: 10.1371/journal.pone.0097591] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 04/22/2014] [Indexed: 11/18/2022] Open
Abstract
PURPOSE In this study, spectral analysis of the deformation signal from Corvis-ST (CoST) and reflected light intensity from ocular response analyzer (ORA) was performed to evaluate biomechanical concordance with each other. METHODS The study was non-interventional, observational, cross-sectional and involved 188 eyes from 94 normal subjects. Three measurements were made on each eye with ORA and CoST each and then averaged for each device. The deformation signal from CoST and reflected light intensity (applanation) signal from ORA was compiled for all the eyes. The ORA signal was inverted about a line joining the two applanation peaks. All the signals were analyzed with Fourier series. The area under the signal curves (AUC), root mean square (RMS) of all the harmonics, lower order (LO included 1st and 2nd order harmonic), higher order (HO up to 6th harmonic), CoST deformation amplitude (DA), corneal hysteresis (CH) and corneal resistance factor (CRF) were analyzed. RESULTS The device variables and those calculated by Fourier transform were statistically significantly different between CoST and ORA. These variables also differed between the eyes of the same subject. There was also statistically significant influence of eyes (left vs. right) on the differences in a sub-set of RMS variables only. CH and CRF differed statistically significantly between the eyes of subject (p<0.001) but not DA (p = 0.65). CONCLUSIONS CoST was statistically significantly different from ORA. CoST may be useful in delineating true biomechanical differences between the eyes of a subject as it reports deformation.
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Affiliation(s)
- Sushma Tejwani
- Glaucoma Service, Narayana Nethralaya, Bangalore, Karnataka, India
| | - Rohit Shetty
- Refractive Surgery, Narayana Nethralaya, Bangalore, Karnataka, India
| | - Mathew Kurien
- Cataract Surgery, Narayana Nethralaya, Bangalore, Karnataka, India
| | | | - Arkasubhra Ghosh
- Gene, Repair and Regeneration in Ocular Workstation (GROW research lab), Narayana Nethralaya, Bangalore, Karnataka, India
| | - Abhijit Sinha Roy
- Imaging, Biomechanics and Mathematical Modeling Solutions (IBMS) lab, Narayana Nethralaya, Bangalore, Karnataka, India
- * E-mail:
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Asejczyk-Widlicka M, Krzyżanowska-Berkowska P, Kowalska M, Iskander DR. Clinical utility of spectral analysis of intraocular pressure pulse wave. BMC Ophthalmol 2014; 14:30. [PMID: 24620786 PMCID: PMC3975190 DOI: 10.1186/1471-2415-14-30] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Accepted: 03/03/2014] [Indexed: 12/01/2022] Open
Abstract
Background To evaluate the clinical utility of spectral analysis of intraocular pressure pulse wave in healthy eyes of a control group (CG), patients having glaucomatous optic disc appearance or ocular hypertension, and patients with primary open angle glaucoma or primary angle closure glaucoma. Methods This is a prospective study that enrolled 296 patients from a single glaucoma clinic. Age matched CG consisted of 62 individuals. Subjects underwent comprehensive clinical diagnostic procedures including intraocular pressure (IOP) measurement with dynamic contour tonometry (DCT) and Goldmann applanation tonometry (GAT). DCT time series were analyzed with custom written software that included signal preprocessing, filtering and spectral analysis. An amplitude and energy content analysis, which takes into account non-stationarity of signals but also provides methodology that is independent of IOP and ocular pulse amplitude (OPA) levels, was applied. Spectral content up to the 6th harmonic of the pressure pulse wave was considered. Statistical analyses included descriptive statistics, normality test, and a multicomparison of medians for independent groups using Kruskal-Wallis test. Results GAT IOP showed statistical significance (Kruskal-Willis test p < 0.05) for three out of 10 considered multiple comparisons, DCT IOP and OPA showed statistically significant results in five and seven cases, respectively. Changes in heart rate and central corneal thickness between the groups were statistically significant in two cases. None of the above parameters showed statistically significant differences between CG and the suspects with glaucomatous optic disc appearance (GODA). On the other hand, spectral analysis showed statistically significant differences for that case. Conclusions Spectral analysis of the DCT signals was the only method showing statistically significant differences between healthy eyes and those of GODA suspects.
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Affiliation(s)
- Magdalena Asejczyk-Widlicka
- Faculty of Materials, Strength and Welding, Wroclaw University of Technology, Smoluchowskiego 25, 50-372 Wroclaw, Poland.
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