# Numerical Simulation on Corneal Surface Behavior Applying Luminous Beam Levels
## 2 Materials and Methods  
### Three-Dimensional Model  
The 3D modeling procedure considers the human eyeball and the main parts composing it. First, research was done on the accurate dimensions of the visual organ of the 50 th global percentile [26]; then, the measurements were obtained with clinical reports and literature. Further, a 2D sketch was created to validate it and develop a 3D detailed design; finally, we created the numerical simulation considering the 3D model and the study cases. This research presents a complete 3D model of the human organ; it was considered a topographic study, and we obtained the values in Table 1.  
Based on the same study and the literature, considering the 2D sketch, a 3D model was developed on the computer program SolidWorks(r) 2022 by Dassault Systemes, Velizy-Villacoublay (France). Since the eye is composed of two liquids (99% water), the vitreous and aqueous humor [27], in addition, the capsule of the lens is considered, and it is a vital element in the capability of the organ to collect external stimuli and its purpose as a barrier; it is divided into three parts: the lens capsule, the cortex of the lens, and the nucleus of the lens. It is essential to add these elements to the model because the current study of this research focuses on the analysis of light waves under the surface of the eyeball. The  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Zone** & **Dimensions** \\ \hline Cornea & D: 10 mm. Volume: 57.5 mm\({}^{3}\). Thickness: 0.5 mm. \\ \multirow{2}{*}{Sclera} & Different thicknesses. Leaf blade: 0.8 mm. Equator: 0.4 mm. \\  & Optic nerve insertion: 4.5 mm. \\ \multirow{2}{*}{Iris} & D: 12.33 mm. Ang. iris-cornea = 56\({}^{\circ}\). Iris-crystalline distance \\  & 1.8 mm. Corrugated. \\ \multirow{2}{*}{Pupil} & D: 3 mm. \"Its diameter is between 3 and 4.5 millimeters in the \\  & human eye. It can widen to between 5 to 9 mm in the dark\". \\ \multirow{2}{*}{Crystalline} & Three layers and greater curvature is the back face. Capsule \\  & thickness: 0.5 mm. Core: 2.1 mm. \\ \multirow{2}{*}{Ciliary muscle/ciliary body} & Thickness: 0.6 mm. Distance between the ciliary muscle and \\  & ciliary body: 0.35-0.3 mm. \\ \multirow{2}{*}{Choroid} & Thickness: 0.4 mm \\ \multirow{2}{*}{Retina} & Different thicknesses. Periphery: 2 mm, optic nerve insertion: \\  & 5 mm. \\ \multirow{2}{*}{Pos/Ante Camera} & Vol ante: 192 mm\({}^{3}\). \\ \multirow{2}{*}{Eyelids/Corneal cavity} & Different thicknesses. Leaf blade: 1 mm. Equator: \\  & 1.5 mm/sclera–cavity space: 0.1 mm. Thickness: 1.5 mm. \\ \multirow{2}{*}{Axial length} & ”Their distances vary between 12–14.5 mm at their maximum \\  & opening, and 3.5 mm is considered the minimum”. \\ \multirow{2}{*}{Axial length} & 24.66 mm. \\ \hline \hline \end{tabular}
\end{table}
Table 1: Dimensions of the specific parts of the human organ, 50 th percentile.  
thickness of the capsule was 0.5 mm, and the diameter of the nucleus was 2.1 mm; the study mainly considers the corneal behavior due to loads on the surface with luminous beams. Furthermore, it is important to consider these internal layers where the luminous lengths can breach them. Figure 1 shows a cross-section view of the eyeball reconstruction.  
From the data shown in Table 1, it was possible to reconstruct a 3D model of the visual organ and apply specific mechanical properties for each part to develop the numerical analysis. In the model, the vitreous humor was removed to appreciate its features better, as shown in Figure 1.