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Translaminar Autonomous System Model for the Modulation of Intraocular and Intracranial Pressure in Human Donor Posterior Segments
Published on: April 24, 2020
Novel pressure-to-cornea index in glaucoma
Milko E Iliev1, Alexander Meyenberg, Ernst Buerki
1Department of Ophthalmology, University of Bern, Inselspital, 3010 Bern, Switzerland. milko.iliev@insel.ch
The British Journal of Ophthalmology
|May 15, 2007
Summary
A new Pressure-to-Cornea Index (PCI) integrates intraocular pressure (IOP) and central corneal thickness (CCT) to better assess glaucoma risk. PCI shows promise in identifying glaucoma susceptibility compared to existing IOP correction formulas.
Area of Science:
- Ophthalmology
- Glaucoma Research
- Biomedical Engineering
Background:
- Existing formulas for correcting intraocular pressure (IOP) based on central corneal thickness (CCT) have limitations.
- Central corneal thickness (CCT) is recognized as an independent risk factor for glaucoma.
- A novel index, Pressure-to-Cornea Index (PCI), is proposed to unify IOP and CCT into a single risk factor.
Purpose of the Study:
- To introduce and define the Pressure-to-Cornea Index (PCI = IOP/CCT³).
- To investigate the distribution of PCI in normal controls and glaucoma patient groups.
- To evaluate PCI's diagnostic performance against established IOP correction formulas.
Main Methods:
- PCI was calculated using ultrasound pachymetry for CCT.
- PCI distribution was analyzed in 220 controls, 53 normal-tension glaucoma (NTG), 76 ocular hypertension (OHT), and 89 primary open-angle glaucoma (POAG) patients.
- Receiver operating characteristic (ROC) curves were used to compare PCI's discriminative ability with existing formulas.
Main Results:
- Mean PCI values varied significantly across groups: Controls (92.0), NTG (129.1), OHT (134.0), and POAG (173.6).
- PCI demonstrated superior area under the ROC curve (AUC) compared to correction formulas.
- PCI showed significantly higher sensitivity at 80% and 90% specificities, with an optimal cut-off value of 133.8.
Conclusions:
- A PCI range of 120-140 is suggested as the upper limit for normality.
- PCI may serve as a valuable glaucoma risk factor by reflecting individual susceptibility to IOP.
- Further longitudinal studies are required to confirm the prognostic value of PCI.
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