Effects of Peripapillary Scleral Stiffening on the Deformation of the Lamina Cribrosa

Abstract

PurposeScleral stiffening has been proposed as a treatment for glaucoma to protect the lamina cribrosa (LC) from excessive intraocular pressure–induced deformation. Here we experimentally evaluated the effects of moderate stiffening of the peripapillary sclera on the deformation of the LC.MethodsAn annular sponge, saturated with 1.25% glutaraldehyde, was applied to the external surface of the peripapillary sclera for 5 minutes to stiffen the sclera. Tissue deformation was quantified in two groups of porcine eyes, using digital image correlation (DIC) or computed tomography imaging and digital volume correlation (DVC). In group A (n = 14), eyes were subjected to inflation testing before and after scleral stiffening. Digital image correlation was used to measure scleral deformation and quantify the magnitude of scleral stiffening. In group B (n = 5), the optic nerve head region was imaged using synchrotron radiation phase-contrast microcomputed tomography (PC μCT) at an isotropic spatial resolution of 3.2 μm. Digital volume correlation was used to compute the full-field three-dimensional deformation within the LC and evaluate the effects of peripapillary scleral cross-linking on LC biomechanics.ResultsOn average, scleral treatment with glutaraldehyde caused a 34 ± 14% stiffening of the peripapillary sclera measured at 17 mm Hg and a 47 ± 12% decrease in the maximum tensile strain in the LC measured at 15 mm Hg. The reduction in LC strains was not due to cross-linking of the LC.ConclusionsPeripapillary scleral stiffening is effective at reducing the magnitude of biomechanical strains within the LC. Its potential and future utilization in glaucoma axonal neuroprotection requires further investigation.

Corneoscleral stiffening increases IOP spike magnitudes during rapid microvolumetric change in the eye

“…The tissue was treated for a total of 40 minutes and the solution in all groups was exchanged afresh every 13 minutes. This treatment protocol was designed to induce sufficient tissue fixation/stiffening based on previous experiments (Coudrillier et al, 2016; Liu and He, 2009; Spoerl and Seiler, 1999; Thornton et al, 2009). Given the small volume that can be held by the rubber ring, we replenished the solution to avoid the depletion of effective fixative molecules over time.…”

“…Corneal stiffening has become a clinical therapy for keratoconus and other corneal conditions (Iseli et al, 2008; Wollensak et al, 2003). Stiffening of the posterior sclera has also been proposed as a potential treatment for glaucoma (Campbell et al, 2017; Coudrillier et al, 2016; Kimball et al, 2014) and myopia (Dotan et al, 2014; Liu et al, 2016; Wollensak and Spoerl, 2004). It would therefore be interesting to evaluate the level of changes in dynamic IOP that can be expected with localized stiffening of the ocular shell.…”

Biomechanical aspects of axonal damage in glaucoma: A brief review

“…Pig, cat and dog eyes have a well-developed LC (Coudrillier et al, 2016a; Coudrillier et al, 2016b; Fatehee et al, 2011; Grozdanic et al, 2010; Radius and Bade, 1982a, b), but their ONH vascular anatomy is considerably different to that of the human (De Schaepdrijver et al, 1989; May, 2008). Glaucoma commonly caused by anterior segment dysgenesis and high IOP is a frequent condition seen in cats and dogs (McLellan and Miller, 2011; Pizzirani, 2015).…”

Digital Volume Correlation: Review of Progress and Challenges

“…Other applications followed in the field of biomechanics (e.g., see Refs. [194,11,106,241,17,193,44,40,43,109]). At the beginning of the current decade, DVC was clearly identified as one technique very suited to biomechanical applications [239].…”