Geometrical Custom Modeling of Human Cornea In Vivo and Its Use for the Diagnosis of Corneal Ectasia

PLOS ONE, Dec 2019

Aim To establish a new procedure for 3D geometric reconstruction of the human cornea to obtain a solid model that represents a personalized and in vivo morphology of both the anterior and posterior corneal surfaces. This model is later analyzed to obtain geometric variables enabling the characterization of the corneal geometry and establishing a new clinical diagnostic criterion in order to distinguish between healthy corneas and corneas with keratoconus. Method The method for the geometric reconstruction of the cornea consists of the following steps: capture and preprocessing of the spatial point clouds provided by the Sirius topographer that represent both anterior and posterior corneal surfaces, reconstruction of the corneal geometric surfaces and generation of the solid model. Later, geometric variables are extracted from the model obtained and statistically analyzed to detect deformations of the cornea. Results The variables that achieved the best results in the diagnosis of keratoconus were anterior corneal surface area (ROC area: 0.847, p<0.000, std. error: 0.038, 95% CI: 0.777 to 0.925), posterior corneal surface area (ROC area: 0.807, p<0.000, std. error: 0.042, 95% CI: 0,726 to 0,889), anterior apex deviation (ROC area: 0.735, p<0.000, std. error: 0.053, 95% CI: 0.630 to 0.840) and posterior apex deviation (ROC area: 0.891, p<0.000, std. error: 0.039, 95% CI: 0.8146 to 0.9672). Conclusion Geometric modeling enables accurate characterization of the human cornea. Also, from a clinical point of view, the procedure described has established a new approach for the study of eye-related diseases.

A PDF file should load here. If you do not see its contents the file may be temporarily unavailable at the journal website or you do not have a PDF plug-in installed and enabled in your browser.

Alternatively, you can download the file locally and open with any standalone PDF reader:

https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0110249&type=printable

Geometrical Custom Modeling of Human Cornea In Vivo and Its Use for the Diagnosis of Corneal Ectasia

et al. (2014) Geometrical Custom Modeling of Human Cornea In Vivo and Its Use for the Diagnosis of Corneal Ectasia. PLoS ONE 9(10): e110249. doi:10.1371/journal.pone.0110249 Geometrical Custom Modeling of Human Cornea In Vivo and Its Use for the Diagnosis of Corneal Ectasia Francisco Cavas-Martnez 0 Daniel G. Ferna ndez-Pacheco 0 Ernesto De la Cruz-Sa nchez 0 Jose Nieto Martnez 0 Francisco J. Ferna ndez Can avate 0 Alfredo Vega-Estrada 0 Ana B. Plaza-Puche 0 Jorge L. Alio 0 Alexander V. Ljubimov, Cedars-Sinai Medical Center; UCLA School of Medicine, United States of America 0 1 Department of Graphical Expression, Technical University of Cartagena , Cartagena , Spain , 2 Department of Physical Activity and Sport, University of Murcia , Murcia, Spain, 3 Vissum Corporacio n Oftalmolo gica, Alicante , Spain Aim: To establish a new procedure for 3D geometric reconstruction of the human cornea to obtain a solid model that represents a personalized and in vivo morphology of both the anterior and posterior corneal surfaces. This model is later analyzed to obtain geometric variables enabling the characterization of the corneal geometry and establishing a new clinical diagnostic criterion in order to distinguish between healthy corneas and corneas with keratoconus. Method: The method for the geometric reconstruction of the cornea consists of the following steps: capture and preprocessing of the spatial point clouds provided by the Sirius topographer that represent both anterior and posterior corneal surfaces, reconstruction of the corneal geometric surfaces and generation of the solid model. Later, geometric variables are extracted from the model obtained and statistically analyzed to detect deformations of the cornea. Results: The variables that achieved the best results in the diagnosis of keratoconus were anterior corneal surface area (ROC area: 0.847, p,0.000, std. error: 0.038, 95% CI: 0.777 to 0.925), posterior corneal surface area (ROC area: 0.807, p,0.000, std. error: 0.042, 95% CI: 0,726 to 0,889), anterior apex deviation (ROC area: 0.735, p,0.000, std. error: 0.053, 95% CI: 0.630 to 0.840) and posterior apex deviation (ROC area: 0.891, p,0.000, std. error: 0.039, 95% CI: 0.8146 to 0.9672). Conclusion: Geometric modeling enables accurate characterization of the human cornea. Also, from a clinical point of view, the procedure described has established a new approach for the study of eye-related diseases. - Data Availability: The authors confirm that, for approved reasons, some access restrictions apply to the data underlying the findings. Data are available from the Vissum Institutional Data Access / Ethics Committee for researchers who meet the criteria for access to confidential data. The contact person to request data is Jorge Alio. His email is . Funding: The authors have no support or funding to report. Competing Interests: Three authors are researchers employed by Vissum Corporacion S.L. These three authors do not have any competing interest or financial disclosure interest in this collaborative research. This does not alter the authors adherence to PLOS ONE policies on sharing data and materials. Characterization of corneal topography is critical for the assessment of vision quality and for several clinical applications including the diagnosis and management of corneal diseases [13], the planning of refractive surgery [45], and the construction of corneal numerical models [6]. At present, several non-invasive technologies that do not require the use of anesthesia or contact with the cornea have been developed for the comprehensive characterization of corneal topography. These include Scheimpflug photography [7], a combination of scanning-slit and Placido-disc technologies [8], very-high-frequency ultrasonography [9], and optical coherence tomography [1012]. Scheimpflug photographybased systems allow the study and characterization of both anterior and posterior corneal surfaces [1314]. Different studies have validated the consistency of the measurements obtained with this technique, using different commercially available devices [1516]. The combination of accurate Scheimpflug photography analysis for corneal characterization with classical Placido-disc technology [17] has been recently developed, with the aim of maintaining the benefits of the Scheimpflug technology and optimizing the measurements of the anterior corneal curvature. This combined technology has been shown to provide highly consistent anterior and posterior corneal curvature measurements [1820]. These data allow the human cornea to be modeled in order to detect corneal ectatic disorders, such as keratoconus. Modeling of the human cornea can be approached by two different strategies: i) using a generic model which is valid to reproduce and extract results that can be applied to the whole population, or ii) creating a personalized model that allows the particular case of a specific patient to be studied. Both types of models have (...truncated)


This is a preview of a remote PDF: https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0110249&type=printable

Francisco Cavas-Martínez, Daniel G. Fernández-Pacheco, Ernesto De la Cruz-Sánchez, José Nieto Martínez, Francisco J. Fernández Cañavate, Alfredo Vega-Estrada, Ana B. Plaza-Puche, Jorge L. Alió. Geometrical Custom Modeling of Human Cornea In Vivo and Its Use for the Diagnosis of Corneal Ectasia, PLOS ONE, 2014, Volume 9, Issue 10, DOI: 10.1371/journal.pone.0110249