TAILIEUCHUNG - Chapter 029. Disorders of the Eye (Part 13)

Vitreous Degeneration This occurs in all individuals with advancing age, leading to visual symptoms. Opacities develop in the vitreous, casting annoying shadows upon the retina. As the eye moves, these distracting "floaters" move synchronously, with a slight lag caused by inertia of the vitreous gel. Vitreous traction upon the retina causes mechanical stimulation, resulting in perception of flashing lights. This photopsia is brief and confined to one eye, in contrast to the bilateral, prolonged scintillations of cortical migraine. Contraction of the vitreous can result in sudden separation from the retina, heralded by an alarming shower of floaters and photopsia | Chapter 029. Disorders of the Eye Part 13 Vitreous Degeneration This occurs in all individuals with advancing age leading to visual symptoms. Opacities develop in the vitreous casting annoying shadows upon the retina. As the eye moves these distracting floaters move synchronously with a slight lag caused by inertia of the vitreous gel. Vitreous traction upon the retina causes mechanical stimulation resulting in perception of flashing lights. This photopsia is brief and confined to one eye in contrast to the bilateral prolonged scintillations of cortical migraine. Contraction of the vitreous can result in sudden separation from the retina heralded by an alarming shower of floaters and photopsia. This process known as vitreous detachment is a frequent involutional event in the elderly. It is not harmful unless it damages the retina. A careful examination of the dilated fundus is important in any patient complaining of floaters or photopsia to search for peripheral tears or holes. If such a lesion is found laser application can forestall a retinal detachment. Occasionally a tear ruptures a retinal blood vessel causing vitreous hemorrhage and sudden loss of vision. On attempted ophthalmoscopy the fundus is hidden by a dark red haze of blood. Ultrasound is required to examine the interior of the eye for a retinal tear or detachment. If the hemorrhage does not resolve spontaneously the vitreous can be removed surgically. Vitreous hemorrhage also occurs from the fragile neovascular vessels that proliferate on the surface of the retina in diabetes sickle cell anemia and other ischemic ocular diseases. Retinal Detachment This produces symptoms of floaters flashing lights and a scotoma in the peripheral visual field corresponding to the detachment Fig. 29-14 . If the detachment includes the fovea there is an afferent pupil defect and the visual acuity is reduced. In most eyes retinal detachment starts with a hole flap or tear in the peripheral retina rhegmatogenous retinal .

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