International Journal of Engineering Science 158 (2021) 103414 Contents lists available at ScienceDirect International Journal of Engineering Science journal homepage: www.elsevier.com/locate/ijengsci On the shell model for human eye in Glaucoma disease Shahriar Dastjerdi a , Bekir Akgöz a , Ömer Civalek b,∗ a Division of Mechanics, Civil Engineering Department, Akdeniz University, Antalya, Turkey b China Medical University, Taichung, Taiwan a r t i c l e i n f o Article history: Received 27 August 2020 Accepted 25 October 2020 Keywords: Glaucoma Biomechanical modelling Viscoelastic Spherical geometry First-order shear deformation theory a b s t r a c t A new mechanical and analytical models of the human eye is presented in order to study Glaucoma disease and its complications. Mechanical modeling of the human eye is per- formed with a hollow sphere under internal pressure. The first-order shear deformation theory is used to obtain the governing equations of the model, which are the set of partial differential equations. The nonlinear von Kármán assumption is considered for strain field to obtain the more precise results. The viscoelastic effects on the material structure of the eye are also considered to be more consistent with the results. The obtained governing equations and boundary conditions are solved using Semi-Analytical Polynomial Method. The results are studied for Glaucoma and the effects of this disease on the patient’s vi- sion as well as the temporary and permanent deformities caused in the patient’s eyeball are further investigated. The modeling and information obtained from this study can help clinicians to provide more appropriate therapeutic strategies. Stress concentration can be identified in the eyeball tissue of patients suffering from Glaucoma using the simulations presented in this study. Given the generality of the proposed model, not only Glaucoma disease but also a wide range of eye diseases can be studied. © 2020 Elsevier Ltd. All rights reserved. 1. Introduction Glaucoma is actually a group of eye diseases caused by elevated pressure in the eye. This disease is the second leading cause of vision loss in the world after cataract. The common cause of glaucoma can be a problem in the intraocular fluid outflow from the iris (colored eye circle) and this can occur for a variety of reasons, including irritation or even blockage of the outlet. Those are next to the iris due to bleeding. Glaucoma can generally be divided into two types of open-angle glaucoma and closed-angle glaucoma. In the first type (wide angle), about 90% of glaucoma cases in the United States. There are no sudden and acute signs and symptoms and no pain. The only progressive symptoms are a decrease in visual field and optic nerve changes. And in type 2 (closed angle), less than 10% of glaucoma cases in the United States but more than half of glaucoma in other countries, especially Asian countries. About 10% of closed angle patients suffer from acute attacks and crises including sudden pain in eye, sighting around the headlights, very high intraocular pressure (greater than 30 mmHg), nausea and vomiting, sudden loss of vision, and dilated pupils. In some cases, oval pupils also appear. Closed angle type of glaucoma is an emergency situation. Also, there is another type of congenital glaucoma. Congenital glaucoma in infants is characterized by symptoms of tears, blindness to light or fear of light, and eyelid retraction. Sometimes the cornea becomes large and opaque. A large number of studies were performed on glaucoma disease and its effects (Jain, Bhoot, and ∗ Corresponding author. E-mail address: civalek@yahoo.com (Ö. Civalek). https://doi.org/10.1016/j.ijengsci.2020.103414 0020-7225/© 2020 Elsevier Ltd. All rights reserved.