Purpose: To compare corneal hysteresis (CH) and corneal resistance factor (CRF) measured with the Ocular Response Analyzer (ORA) in patients with primary open-angle glaucoma (POAG), patients with ocular hypertension (OHT), and normal subjects (NL); and to assess correlations of CH and CRF with corneal-compensated intraocular pressure (IOPcc), Goldmann applanation tonometry (GAT), glaucoma type, central corneal thickness (CCT), previous filtering procedure, and antiglaucoma medications.
Methods: A total of 108 POAG, 22 OHT, and 24 NL were enrolled in this observational study. Goldmann applanation tonometry and ORA were performed in a randomized sequence followed by pachymetry. One eye per subject was selected at random for analysis. Chi-square, Wilcoxon, and Kruskal-Wallis tests were used for comparison and Spearman coefficient for assessing correlations.
Results: Mean CH and CRF were significantly lower in POAG than in OHT and NL. Ocular Response Analyzer IOPcc overestimated IOP compared to GAT only in POAG. This difference increased with higher GAT. Goldmann applanation tonometry and IOPcc were correlated. Corneal hysteresis was negatively correlated with age in POAG. Corneal resistance factor and CH were positively correlated with CCT in POAG and OHT. Unlike CRF, CH was not correlated with GAT in POAG and OHT. Corneal-compensated intraocular pressure was not correlated with CCT. Difference between GAT and IOPcc was not CCT dependent. Corneal hysteresis and CRF were comparable in POAG and NTG, unchanged after filtering procedure. Corneal hysteresis was not altered by topical medications. Corneal resistance factor was significantly lower in treated eyes and those receiving prostaglandin analogues with no correlation with the treatment duration.
Conclusions: Patients with glaucoma seem to have distinctive corneal biomechanical properties compared to OHT and NL. They may be influenced by many other unknown subparameters.
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http://dx.doi.org/10.5301/ejo.2010.2150 | DOI Listing |
J Glaucoma
January 2025
Laboratory of Research and Clinical Applications in Ophthalmology, Aristotle University of Thessaloniki, Thessaloniki, Greece.
Prcis: In 801 participants, corneal hysteresis (CH) was positively associated with female gender and central corneal thickness, and negatively with age and axial length. Diabetes showed no significant association with CH in the adjusted models.
Purpose: To provide values of corneal hysteresis (CH) in an elderly, healthy Greek population and to investigate its association with demographic, ocular, and systemic factors.
Int J Ophthalmol
January 2025
Department of Medical Surgical Nursing, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran 1968653111, Iran.
Biomechanical study of the visual system by ocular response analyzer investigates the inter-structural biological relationships, mechanics, and function of the visual system. This review aimed to investigate the changes in corneal biomechanical parameters with age and sex. The articles published in PubMed between 2000 and 2021 were investigated and critiqued, and valid scientific evidence was collected, reviewed and concluded according to the inclusion and exclusion criteria.
View Article and Find Full Text PDFBr J Ophthalmol
January 2025
Department of Ophthalmology, Severance Hospital, Institute of Vision Research, Yonsei University College of Medicine, Seoul, Seodaemun-gu, Korea (the Republic of)
Background: The present study aims to identify the relationship between longitudinal changes in corneal hysteresis (CH) and progressive retinal nerve fibre layer (RNFL) thinning in a cohort of medically controlled, early-to-moderate open-angle glaucoma (OAG) patients with a history of laser refractive surgery (LRS).
Methods: A total of 123 consecutive eyes with a diagnosis of medically controlled (peak intraocular pressure (IOP)<18 mm Hg), early-to-moderate OAG with a history of LRS underwent measurements of CH, corneal-compensated intraocular pressure (IOPcc) and RNFL thicknesses every 6 months. Linear models were used to investigate the relationship between CH change and RNFL thickness change over time.
Graefes Arch Clin Exp Ophthalmol
January 2025
Department of Ophthalmology, Shimane University Faculty of Medicine, Izumo, Japan.
BMJ Case Rep
December 2024
Ophthalmology, Wellington Regional Hospital, Wellington South, New Zealand
Technologies that describe the biomechanics of the eye are of emerging importance in glaucoma and keratoconus. A defect in the wall of the eye would be expected to affect biomechanics, resulting in the dispersion of mechanical energy and more viscous rather than elastic behaviour. Here, a mildly myopic man in his 50s was noted to have a deep conduit beside the right optic disc which appeared to pass posteriorly to the optic nerve sheath or orbit.
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