Abstract
Purpose :
Traction retinal detachments (TRDs) are the result of complex tractional forces from vitreoretinal proliferative membranes. TRDs will lead to progressive visual loss, reducing the life quality of patients. The general treatment strategy (for TRDs) is to release the tractional forces by dissecting proliferative membranes. The mechanical response of the stretched membrane to the dissection is complex, potentially leading to a force propagation along another direction. Retinal tears and layer damage may occur after the initial cut is made to the TRD. The aim of this research is to develop a model to compute and quantify the mechanical responses of the retinal layers, creating a traction force map of the TRDs.
Methods :
A three-dimensional computational model of the retinal-sclera segment was constructed based on anatomical knowledge and the optical coherence tomography (OCT) scanning information with a Zeiss 5000 OCT system (Fig 1a). The radius of the retinal layer was 12mm, with a thickness of 0.25 mm. A subset image of 2 mm × 2.5 mm was selected with the attached sclera. The material properties of the tissue were adopted from our previous work. Based on the patient-specific OCT scanning, a traction force map was applied onto the surface of the retina. The traction force map was represented in terms of the von Mises stress distribution in tissue.
Results :
The TRDs assessed with OCT and the corresponding computational simulation are shown (Fig 1b, 1c). The computational model demonstrated the highest stress from traction force in the detached retinal tissue. The stress distribution in the retinal layer and sclera are also shown (Fig 2). The stress showed a peak value at the surface of the retinal layer with the greatest detachment. Higher stress was also observed at the detachment margin and correlated with areas of lower curvature. The stress distribution in the sclera only showed a higher value at the detachment margin, with a lower peak value compared with the retinal layer.
Conclusions :
The correlation of peak stress at the site of greatest detachment and at the detachment margin may indicate a plane for detachment propagation, especially at areas of lower curvature along the detachment margin.
This is a 2020 ARVO Annual Meeting abstract.