Keratoconus prognosis study for patients with corneal external mechanical stress mode.

Abstract

To demonstrate the correlation between excessive eye rubbing and corneal degeneration for Keratoconus patients. Keratoconus (KC) patients who regularly rub their eyes had shown a rapid degeneration rate of their affected corneas. This observation is experimentally and numerical discussed and developed based on clinical data of 8 of KC Patients with a mean age of 26.5 ± 9.4years old, and four healthy individuals with a mean age of 24.33 ± 5years old at the baseline. Corneal topography was used to measure both central corneal thickness (CCT) and its total refractive power. The registered data had been exploited to assess the progression of the disease, and the final results were embedded in a finite element model of human corneas to simulate their response to eye rubbing at different stages of the pathology. Corneal lifetime prognosis using multi-layer perceptron was then established to estimate the number of eye rubbing cycles for each stage of KC. The survey of KC patients who declared stopping eye rubbing had shown a decrease in CCT loss rate, followed by a durable stability. Mechanical stresses numerical simulations had shown different corneal behaviours in term of shape deformity, apical raise and corneal applanation between healthy and KC stages models. Apical rise ranged from 0.122 to 0.389mm for an applied intraocular pressure that equals to 15mmHg. A normal stress of 5kPa provoked a corneal applanation that ranged from 0.27mm in healthy cases to 1.173mm in severe stages of the disease. The application of 2.5kPa biaxial stress had resulted normal and tangential applanations that successively ranged from 0.152 and 0.173mm in healthy corneas to 0.446mm and 0.458mm in severe KC stages. An adopted prognosis algorithm was able to predict the current stage of the disease and to estimate the remaining number of eye rubbing cycles before failure. Eye rubbing was proven to be a considerable contributing factor in KC patient's corneal degeneration. The progression of this pathology could be decreased or halted by stopping eye rubbing at early stages.