Abstract
Purpose: :
To evaluate the hypothesis that gas tamponade after repair of retinal detachment significantly alters fluid dynamics within the posterior chamber which reduces the risk of re-detachment of the retina during the critical period after detachment repair
Methods: :
Computational theoretical modelling and analysis of fluid movement and shear forces on the retinal wall were evaluated in the presence of varying degrees of gas and fluid fill within a simulated model of the eye. The same parameters were examined during angular displacement and recti-linear acceleration of the globePractical experiments using a clear Perspex eye model were examined with the same variables and compared to theoretical predictions. A dark fluid was used to fill the eye and fluid dynamics were evaluated through analysis of light passage through the fluid using specific software.
Results: :
The shear stress on the interior of the model depends on whether it is wetted by the liquid. High gas fill decreases the fraction of surface which experiences a large shear stress and also decreases liquid sloshing due to the eye movement. Rapid angular displacement of the eye (around a vertical axis) creates a shear stress of magnitude ~0.01Pa on the retina (which is maximum near the liquid / air interface). Rapid rectilinear acceleration (movement of ~1m/s in 0.1 s) increases the shear stress by two-orders of magnitude to ~1 Pa. The largest shear stress is concentrated around a vertical band along the eye wall perpendicular to the direction of movement. These numerical results are supported by the mathematical models and the physical model of the eye.
Conclusions: :
Gas tamponade after retinal detachment repair significantly alters posterior chamber fluid dynamics and reduces fluid shear on the retinal wall. This may be an important factor which reduces risk of re-detachment of the retina.
Keywords: retinal detachment • computational modeling • vitreoretinal surgery