September 2016
Volume 57, Issue 12
Open Access
ARVO Annual Meeting Abstract  |   September 2016
A Retrospective Clinical Validation Study on the Modelling of Regression, Refractive Change and Morphological Results After Refractive Surgery
Author Affiliations & Notes
  • Riccardo Vinciguerra
    Ophthalmology, Department of Morphological and Surgical Sciences, Insubria University, Varese, Italy
  • Harald Studer
    Optimo Medical AG, Biel, Switzerland
  • paolo vinciguerra
    Eye Center, Humanitas Clinical and Research Center, Rozzano, Italy
  • Footnotes
    Commercial Relationships   Riccardo Vinciguerra, Optimo Medical AG (F); Harald Studer, Optimo Medical AG (E); paolo vinciguerra, Nidek (C), Oculus (C), Schwind (C)
  • Footnotes
    Support  none
Investigative Ophthalmology & Visual Science September 2016, Vol.57, 4865. doi:
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      Riccardo Vinciguerra, Harald Studer, paolo vinciguerra; A Retrospective Clinical Validation Study on the Modelling of Regression, Refractive Change and Morphological Results After Refractive Surgery. Invest. Ophthalmol. Vis. Sci. 2016;57(12):4865.

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      © ARVO (1962-2015); The Authors (2016-present)

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Purpose : Refractive surgery induces modifications in the corneal shape aimed to persist over time.Nevertheless,corneal remodeling can induce regression of the intended correction and limit the optimal outcome of the procedure.The aim of this study was to validate a numerical model of regression,refractive change and morphological results (VRM),with long-term follow-up clinical data of refractive surgery

Methods : Forty-eight eyes of 30 patients who underwent to refractive surgery were included in this retrospective study.Group 1 comprised 20 eyes of 11 patients with unstable topography and refraction, post-operative known regression and high curvature gradient(CG) due to primitive ablation, done several years ago.Group 2 included 20 eyes of 19 patients with stable topography,refraction and low CG, obtained with new ablation profiles
The first available follow-up topography measurement(25±29 in group 1 and 44±14 days in group 2), was imported in the prediction model and subsequently the program was run to create the predicted map at the selected follow-up.Predicted changes of group 1 and 2 were compared to clinical follow-up data

Results : Clinical data of group 1 at 201±21 days of follow-up showed respectively a central and paracentral curvature values of 37.41±2.02D and 42.45±1.61D while the VRM anticipated for the same follow up respectively 37.68±1.95D and 42.31±2.17D.Prediction accuracy was 0.27±0.79D and -0.14±1.50D
Similarly,clinical data of group 2 at 471±130 days of follow-up displayed individually a central and paracentral curvature values of 38.38±2.17D and 40.83±2.42D while the VRM displayed for the selected follow-up respectively 38.81±1.94D and 40.45±2.30D.Prediction accuracy was 0.42±0.43D and -0.38±0.43D
Comparative results showed no significant differences between the real follow up measurements and the VRM predictions in all parameters evaluated (p>0.05)

Conclusions : The statistical analysis showed no significant differences between VRM predictions and clinical data, demonstrating that VRM is able to anticipate remodeling, refractive change and morphological after refractive surgery either in ablation profiles tending regress or the more advanced and stable ones.
The proposed mathematical model, if implemented in the laser software, could permit to avoid regression after refractive surgery by planning an ablation profile that minimizes remodeling

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.


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