To investigate the behavior of silicone oil (SiO) at the steady equilibrium and during saccades and calculate SiO-retina contact, shear stress (SS), and shear rate (SR). Methods:A 24 mm phakic eye mesh model underwent 50°/0.137s saccade. The vitreous chamber compartment was divided into superior and inferior 180°sectors: lens, preequator, postequator, and macula. SiO-retina contact was evaluated as a function of fill percentages between 80% and 90% for a standing patient, 45°upward gaze, and supine. SS and SR for 1000 mPa-s (SiO1000) and 5000 mPa-s (SiO5000) silicon oil were calculated.Results: SiO fill between 80% to 90% allowed 55% to 78% retinal contact. The superior retina always kept better contact with SiO, regardless of the fill percentage (P < 0.01). SiO interface thoroughly contacted the macula only in standing position. SS followed a bimodal behavior and was always significantly higher for SiO5000 compared to SiO1000 (P < 0.01) throughout the saccade. The macula suffered the highest mean SS in standing position, while throughout the saccade the average SS was maximum at the SiO-aqueous interface. SR was significantly higher for SiO1000 compared to SiO5000 (P < 0.001).Conclusions: SS on the retinal surface may instantaneously exceed reported retinal adhesiveness values especially at the SiO-aqueous interface and possibly favor redetachment. Despite 90% SiO fill the inferior retina remains extremely difficult to tamponade.Translational Relevance: Accurate assessment of retina-tamponade interaction may explain recurrent inferior retinal redetachment, silicone oil emulsification, and help to develop better vitreous substitutes.

Purpose To investigate the behavior of silicone oil (SiO) at a steady equilibrium and during saccades in pseudophakic highly myopic eyes with posterior staphyloma with and without an encircling band and compare it to behavior in emmetropic eyes. The SiO–retina contact area and shear stress were calculated by computational fluid dynamics. Methods A numerical model of an emmetropic eye and a myopic eye with and without scleral band underwent a saccade of 50°/0.137 s. The vitreous chamber surface was divided into superior and inferior 180° sectors: lens, pre-equator, post-equator, and macula. SiO–retina contact was evaluated as a function of fill percentages between 80% and 90% for standing, 45° upward tilt, and supine patients. Maximum and average shear stress were calculated. Results Overall, SiO–retina contact ranged between 40% and 83%; fill percentage varied between 80% and 95%. Neither the encircling scleral band nor the staphyloma significantly affected the SiO–retina contact area, although the presence of a scleral band proved disadvantageous when gazing 45° upward. The inferior retina–SiO contact remained below 40% despite 95% SiO fill. The SS significantly increased at the scleral band indentation and decreased elsewhere. The staphyloma greatly reduced shear stress at the macula. Conclusions The presence of a myopic staphyloma reduces shear stress at the macula but does not alter SiO–retina contact significantly. The apposition of a 360° scleral band may reduce SiO–retina contact at least in some postures and increases the SS at the indentation. Translational Relevance Assessing SiO–retina contact when vitreous chamber geometry changes according to pathologic or iatrogenic modifications allows accurate prediction of real-life tamponade behavior and helps explain surgical outcomes.

Numerical simulations of the wind flow around isolated stockpiles of bulk material are performed to assess the emission potential (P) of particulate matter (PM) from the pile surfaces exposed to wind erosion (i.e., industrial wind erosion). The analysis is focused on two metal sulphides (lead and zinc sulphides), which are typically stored in the open yards of industrial plants that operate in the commodity sector for the production of non-ferrous metals. The EPA methodology is applied to the numerical simulated flow fields to quantify the effect of the wind stress over the erodible surfaces of the two ores. Two alternative open bay geometries and different volumes of material stocked within the enclosing walls are considered. Moreover, the protective effect of the walls is assessed by comparing the same pile configurations without walls. This is found to be highly dependent on the wind direction, as well as to the pile configuration. A methodology that can be easily customized to specific industrial sites is proposed to define the best storage configuration for PM emission prevention and control.