A finite element study of posterior eye biomechanics: The influence of intraocular and cerebrospinal pressure on the optic nerve head, peripapillary region, subarachnoid space and meninges

The impact of horizontal eye movements versus intraocular pressure on optic nerve head biomechanics: A tridimensional finite element analysis study

“…The LC had a central thickness of 0.37 mm [ 56 ] and a lateral thickness of 0.30 mm [ 31 ]. The pia mater and arachnoid had a constant width of 0.06 and 0.03 mm [ 35 ], respectively, while the dura mater thickness was 0.4 mm and became thicker close to the sclera [ 8 ]. The SAS was thicker in the anterior part and then became progressively thinner [ 57 ].…”

“…As a final step, to obtain a more detailed analysis of the ONH, postlaminar tissue was segmented into anterior (1 mm from the scleral canal) and posterior regions [ 32 , 35 ]; subsequently, the LC was subdivided into eight concentric zones from its center (four nasal and four temporal), which were then extended to the prelaminar and postlaminar regions, thus obtaining six subregions in the prelaminar tissue and eight in the postlaminar tissue, giving a total of 22 ONH subregions ( Fig. 2 C).…”

“…On the other hand, eye anatomy has typically been reconstructed variably in FE studies. As a result, different eye regions and tissues have been included and excluded in posterior ocular models [ [8] , [9] , [10] , [11] , [12] , [31] , [32] , [33] , [34] , [35] , [36] , [37] ]. Biologically the eye is comprised of three tunics, namely: fibrous (cornea and sclera), vascular (iris, ciliary body, and choroid), and nervous (retina), and it is located within the orbit and surrounded by fat [ 38 ].…”

“…Regarding the optic nerve, typically, the complete meningeal layers have not been included, and in some cases, only the pia mater has been added [ 31 , 33 , 36 ]. In this respect, in a prior FE study we found that ONH strains decreased considerably when meninges were progressively integrated [ 35 ], which suggests that anatomical variability and oversimplification may result in inaccuracy [ 41 ].…”

“…Previously, the present authors reported that under conditions of ocular hypertension, the Young's modulus of the SAS strongly influences ONH and peripapillary region strains [ 35 ]; nevertheless, regarding eye movements, the role of the SAS has not yet been previously explored.…”