Patient-specific simulation of the intrastromal ring segment implantation in corneas with keratoconus.
OBJECTIVE
The purpose of this study was the simulation of the implantation of intrastromal corneal-ring segments for patients with keratoconus. The aim of the study was the prediction of the corneal curvature recovery after this intervention.


METHODS
Seven patients with keratoconus diagnosed and treated by implantation of intrastromal corneal-ring segments were enrolled in the study. The 3D geometry of the cornea of each patient was obtained from its specific topography and a hyperelastic model was assumed to characterize its mechanical behavior. To simulate the intervention, the intrastromal corneal-ring segments were modeled and placed at the same location at which they were placed in the surgery. The finite element method was then used to obtain a simulation of the deformation of the cornea after the ring segment insertion. Finally, the predicted curvature was compared with the real curvature after the intervention.


RESULTS
The simulation of the ring segment insertion was validated comparing the curvature change with the data after the surgery. Results showed a flattening of the cornea which was in consonance with the real improvement of the corneal curvature. The mean difference obtained was of 0.74 mm using properties of healthy corneas.


CONCLUSIONS
For the first time, a patient-specific model of the cornea has been used to predict the outcomes of the surgery after the intrastromal corneal-ring segments implantation in real patients.
Departamento de Sistemas Informáticos y Computación, Universitat Politècnica de València, Camino de Vera s/n, 46022 València, Spain.
M A
MA
Lago
Departamento de Ingeniería Mecánica y Construcción, Universitat Jaume I, Av. de Vicent Sos Baynat, s/n, 12071 Castelló de la Plana, Spain. Electronic address: ruperez@uji.es.
M J
MJ
Rupérez
Departamento de Sistemas Informáticos y Computación, Universitat Politècnica de València, Camino de Vera s/n, 46022 València, Spain.
C
C
Monserrat
Center for Machine Perception, Departament of Cybernetics, Czech Technical University in Prague, Karlovo namesti 13, Prague, Czech Republic.
F
F
Martínez-Martínez
Departamento de Sistemas Informáticos y Computación, Universitat Politècnica de València, Camino de Vera s/n, 46022 València, Spain.
S
S
Martínez-Sanchis
AJL Ophtalmics, Ferdinand Zeppelin Kalea, Vitoria-Gasteiz 01510, Miñano, Araba, Spain.
E
E
Larra
Clínica Optométrica Fundació Lluís Alcanyís, Universitat de València, C/ Guardia Civil, 22 Cantonera amb C/ Vicente Barrera, 46020 València, Spain.
M A
MA
Díez-Ajenjo
Fisabio Oftalmológica Médica, Bifurcación Pío Baroja-general Aviles, S/N, 46015 València, Spain.
C
C
Peris-Martínez
D001696:Biomechanical Phenomena; D003315:Cornea / Q000601:surgery*; D020342:Finite Element Analysis; D006801:Humans; D007640:Keratoconus / Q000601:surgery*; D055595:Mechanical Phenomena; D066230:Patient-Specific Modeling; D019736:Prostheses and Implants
Biomechanical simulation; Cornea; Intrastromal ring segments; Keratoconus