Kai-Jung Chen1, Ashkan Eliasy2, Riccardo Vinciguerra3, Ahmed Abass1, Bernardo T Lopes4, Paolo Vinciguerra5, Renato Ambrósio6, Cynthia J Roberts7, Ahmed Elsheikh8. 1. School of Engineering, University of Liverpool, United Kingdom. 2. School of Engineering, University of Liverpool, United Kingdom. Electronic address: eliasy.ashkan@gmail.com. 3. School of Engineering, University of Liverpool, United Kingdom; Birmingham and Midland Eye Centre, Sandwell and West Birmingham Hospitals, Birmingham, United Kingdom. 4. School of Engineering, University of Liverpool, United Kingdom; Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Brazil; Department of Ophthalmology, Federal University of São Paulo, Brazil. 5. Department of Biomedical Science-Humanitas University, Rozzano, Milan, Italy; Eye Center, Humanitas Clinical and Research Center, Rozzano, Milan, Italy. 6. Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Brazil; Department of Ophthalmology, Federal University of São Paulo, Brazil. 7. Department of Ophthalmology & Visual Science, Department of Biomedical Engineering, Ohio State University, Columbus, Ohio, USA. 8. School of Engineering, University of Liverpool, United Kingdom; NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, United Kingdom; School of Biological Science and Biomedical Engineering, Beihang University (Elsheikh), Beijing, China.
Abstract
PURPOSE: To introduce and clinically validate a new method of estimating intraocular pressure (IOP) in patients with keratoconus and soft corneas with the aim of significantly reducing dependence on corneal biomechanics. SETTING: Vincieye Clinic, Milan, Italy, and Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Brazil. DESIGN: Retrospective case series. METHOD: This study comprised participants enrolled at two hospitals on two continents. Numerical analysis based on the finite element method was performed to simulate the effect of tonometric air pressure of the Corvis ST dynamic Scheimpflug analyzer on eye globes with wide variations in thickness, geometry, and tissue. The numerical predictions of ocular behavior were used to develop a new algorithm to produce predictions of the biomechanically corrected IOP (bIOP) in eyes with a soft cornea (bIOPs). Predictions of the bIOPs were assessed in the keratoconic clinical datasets (because on average these corneas are softer) and compared with the previously developed bIOP algorithm predictions obtained for normal healthy eyes. RESULTS: The study comprised 722 eyes (722 participants). The main outcome was the absence of a significant difference in IOP between healthy eyes and keratoconic eyes when the bIOP and bIOPs algorithms were used (P > .05). There was, however, a significant difference with the uncorrected Scheimpflug analyzer IOP in both groups (P < .001). Furthermore, the bIOPs predictions were significantly less affected by corneal thickness and patient age than the Scheimpflug analyzer IOP. CONCLUSION: The bIOPs algorithm was more reliable at estimating the IOP in eyes with a soft cornea and was validated for use in eyes with keratoconus.
PURPOSE: To introduce and clinically validate a new method of estimating intraocular pressure (IOP) in patients with keratoconus and soft corneas with the aim of significantly reducing dependence on corneal biomechanics. SETTING: Vincieye Clinic, Milan, Italy, and Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Brazil. DESIGN: Retrospective case series. METHOD: This study comprised participants enrolled at two hospitals on two continents. Numerical analysis based on the finite element method was performed to simulate the effect of tonometric air pressure of the Corvis ST dynamic Scheimpflug analyzer on eye globes with wide variations in thickness, geometry, and tissue. The numerical predictions of ocular behavior were used to develop a new algorithm to produce predictions of the biomechanically corrected IOP (bIOP) in eyes with a soft cornea (bIOPs). Predictions of the bIOPs were assessed in the keratoconic clinical datasets (because on average these corneas are softer) and compared with the previously developed bIOP algorithm predictions obtained for normal healthy eyes. RESULTS: The study comprised 722 eyes (722 participants). The main outcome was the absence of a significant difference in IOP between healthy eyes and keratoconic eyes when the bIOP and bIOPs algorithms were used (P > .05). There was, however, a significant difference with the uncorrected Scheimpflug analyzer IOP in both groups (P < .001). Furthermore, the bIOPs predictions were significantly less affected by corneal thickness and patient age than the Scheimpflug analyzer IOP. CONCLUSION: The bIOPs algorithm was more reliable at estimating the IOP in eyes with a soft cornea and was validated for use in eyes with keratoconus.
Authors: William J Foster; Brian W Berg; Steven N Luminais; Amir Hadayer; Shlomit Schaal Journal: Am J Ophthalmol Date: 2022-03-28 Impact factor: 5.488
Authors: Riccardo Vinciguerra; Robert Herber; Yan Wang; Fengju Zhang; Xingtao Zhou; Ji Bai; Keming Yu; Shihao Chen; Xuejun Fang; Frederik Raiskup; Paolo Vinciguerra Journal: Front Med (Lausanne) Date: 2022-02-25