Retina detachment

No influence Circulatory system problems Glaucoma Retina detachment ... 

When the retina becomes detached from the back of the eye, as in the case of nearsightedness or injury sustained in car accidents, it can be weighted down by injecting liquid fluorocarbon After the retina is reattached b> laser surgery or by... 

Sulfur hexafluoride is a gas used as a long-term tamponade (plug) for a retinal hole to repair detached retinas in the eye. If 2.50 g of this compound is introduced into an evacuated 500.0-mL container at 83°C, what pressure in atmospheres is developed ... 

The combination of high intensity and directionality is the basis for laser surgeiy. Essentially, a laser acts as a light knife. In eye surgery, a laser beam can be focused to a tiny spot at the back of the retina. This allows the surgeon to carry out delicate operations such as repairing a detached retina without physically invading the eyeball. 

The incidence and severity of ROP both rise with decreasing birthweight and gestational age. Fielder et al. (1992) have shown that the incidence of ROP in infents of < 1700 g birthweight is about 50%, although only 5% had severe disease. Severe ROP results in vitreous haemorrhage from new vessel formation on the immature retina, retinal traction and eventually retinal detachment (Fig. 9.6). In the most severe cases, retinal detachment is complete, resulting in total blindness. Treatment with cryotherapy or laser has halved the incidence of retinal detachment. 

TGF-P Bone healing, skin ulcers, detached retinas... 

Rhegmatogenous retinal detachment (RD) is defined by fluid accumulation in the subretinal space through retinal tear, inducing separation of the neurosensory retina from the retinal pigmentary epithelium (Fig. 1). 

S. Wolf, V. Schdn, P. Meier, P. Wiedemann, Silicone oil-RMN3 mixture ( heavy silicone oil ) as internal tamponade for complicated retinal detachment, Retina 23 (2003) 335-342. 

Primary (idiopathic, rhegmatogeneous) retinal detachment is induced by a retinal tear, followed by penetration of vitreous fluid between the sensoric retina and the pigment epithelium. 

Tractional retinal detachment is the result of the shrinkage of membranes. This is a frequent event in proliferative vitreretinopathy (PVR), which is characterised by the growth of membranes on the outer as well as on the inner side of the detached retina. The shrinkage of these membranes results in further detachments of the retina and additional retinal holes. 

The status of the retina has not changed it is still detached, very frequently with idiopathic or iatrogenic liquid between the sensoric retina tissue and the underlying vascular layer (choroidea). 

The advantage of the partially fluorinated compounds lies more in their potential to mix with silicone oil. Various groups started activities to diversify the portfolio of silicone oils used as long-term endotamponades to enable a reattachment of a detached retina. Dimethylsiloxanes of different viscosities are well established but their use is limited to the treatment of the upper quadrants of the retina. This is because a 100% filling of the vitreous cavity cannot be achieved, which means that because of their specific gravity, which is 0.97 g/ml, they float on top of the aqueous material present in the vitreous... 

Other uses of lasers include eye surgery on detached retinas, spot welding, holography, isotope separation, accurate determination of the moon s orbit by reflection of laser light off a reflector placed on the moon s surface, and laser-guided bombs and missiles. Possible future uses include terrestrial and extraterrestrial communication, applications to computers, and production of the high temperatures needed for controlled nuclear-fusion reactions. 

The retina is the light-sensitive layer which forms a sort of carpet on the inside of the eye. It sometimes happens—especially in old age—that this carpet becomes detached from the eyeball and floats in the surrounding liquid. In the areas of detached retina vision is of course lost. 

Before the development of this laser welding technique, the repair of a detached retina required major surgery the photophysical process is now the technique of choice. 

Retinal detachment is a major cause of vision loss in adults. The usual treatment is the scleral buckle, which is a silicone band sewn to the outside of the eye that compresses the wall of the eye inward to close the holes in the retina. Sterically stabilized 4-10 nm magnetic particles in a poly(di-methylsiloxane) biocompatible fluid can be held in place with an external magnetized scleral buckle, thus providing a stable internal blockage that... 

An asymptomatic patient with a mild PCO found on slit-lamp examination does not need to be treated. When the patient becomes symptomatic with decreased vision, glare, or visual distortion such that their daily activities are affected, neodymium (Nd) YAG laser capsulotomy should be considered. Nd YAG laser photodisrupts the involved tissues (Figure 30-12) and represents a low risk for a retinal break after the procedure. Therefore, before the Nd YAG treatment, the patient should have a careful dilated examination of the peripheral retina to rule out breaks or degeneration that could lead to retinal detachment after capsulotomy. 

Patients presenting with a retinal detachment typically report an onset of flashing lights (photopsia) and floaters. Patients may also report decreased peripheral or central vision. Any patient presenting with these symptoms requires prompt dilation and a thorough examination of the central and peripheral retina. Slit-lamp biomicroscopy and indirect ophthalmoscopy with scleral depression are... 

The most common symptoms reported by patients are changes in color vision and impaired vision. These symptoms can take many forms and include the visual phenomena listed in Box 35-4. A common symptom is snowy vision (objects appear to be covered with frost or snow), and this observation is intensified in brightly illuminated environments. There is also evidence that digoxin may contribute to rhegmatogenous retinal detachment by decreasing the normal adhesion of the retina to the RPE. 

Retinal neovascularization as a consequence of talc injection can occur in the retinal periphery as neovascu-lar tufts in the shape of sea fens at the junction of the perfused and nonperfused retina.This is a potentially serious complication of talc emboli, because it can lead to retinal detachment, massive vitreal hemorrhage, and optic disc neovascularization. 

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