Increasing Silicone Oil Viscosity Increases Resistance to Volume Displacement in an in vitro Retinal Detachment Model.

PURPOSE: To determine whether higher-viscosity silicone oils offer greater resistance to volume displacement in an in vitro eye model of retinal detachment and could subsequently be expected to generate stronger retinal tamponades in cases of recurrent or complex retinal detachments. METHODS: We used an eye model that included a membrane representing the retina. Silicone oils with different viscosities were injected, and oil displacement and resistance were measured. RESULTS: Membrane movement and volume changes in an eye model were proportional to the viscosity of the oil: the lower the viscosity, the faster volume changes and displacement occurred. CONCLUSIONS: Our results show that the volume change rate has a linear relationship with oil viscosity. Our findings suggest that in this eye model, silicone oil tamponades the retina against the retinal pigment epithelium mainly through volume displacement and that silicone oil viscosity may play an important role in preventing retinal displacement and in providing tamponade.

Ocular Paintball Injuries.

UNLABELLED: Background: One of the most alarming ocular injury trends in recent years has been the proliferation of paintball guns and the proportional increase in the number of ocular eye injuries caused by paintballs. OBJECTIVES: To describe five cases of paintball eye injuries that resulted in loss of functional vision in four of them. METHODS: We conducted a retrospective review of the clinical course in five patients with paintball eye injuries treated in the ophthalmology departments of two medical centers. RESULTS: Five young males were evaluated for paintball injuries caused by blunt trauma. There was one case of full-thickness laceration (globe rupture). Four patients required one to five surgical interventions: three of these involved the removal of traumatic cataract including two eyes with significant zonular dehiscence treated by lens capsule conservation using anchoring devices, one retinal surgery and two glaucoma filtration surgeries. However, final visual outcome was not favorable due to irreversible retinal damage. CONCLUSIONS: Paintball trauma often results in significant ocular injury and loss of functional vision despite successful surgical intervention. Most injuries occur in under-supervised settings and are easily preventable. Improved safety measures, strict regulation enforcement and appropriate public education could prevent such serious damage.

The placental factor in spontaneous preterm labor with and without premature rupture of membranes.

AIM: The association between infection and inflammatory response in preterm labor (PTL) is well established. Our aim was to elucidate the roles of utero-placental perfusion and fetal component, in PTL. METHODS: Histopathologic findings in placentas from pregnancies complicated by preterm birth with or without premature rupture of membranes (ROM) (study group) were compared to placentas from pregnancies with delivery >34 weeks, with or without spontaneous ROM (control group). Placental lesions were classified as those consistent with maternal circulation abnormalities, maternal underperfusion, vascular or villous changes, and those consistent with fetal thrombo-occlusive disease, vascular or villous changes. Lesions were analyzed by maternal or fetal origin of inflammatory response. RESULTS: The study group of 68 women, had a higher rate of vascular lesions than controls (136 women, 26.5% vs. 11%, P=0.005) and of inflammatory lesions of maternal and fetal origin (P<0.001). Within the study group, inflammatory lesions were more common in those with ruptured membrane than in those without (P<0.001). CONCLUSIONS: Placentas from preterm birth demonstrate vascular lesions of maternal origin, in addition to the known inflammatory process. Preterm premature membrane rupture is associated with an increased rate of inflammatory lesions relative to spontaneous intact membranes-preterm birth, suggesting a different underlying mechanism.