Neuro-Opthalmology Flashcards
What is hemianopsia?
Hemianopsia is a clinical term used to describe the loss of one half a vertical visual field.
What is macular degeneration?
Macular degeneration is loss of pigment in the macular region of the retina, usually affecting those over age 50. Macular degeneration is a common disease of unknown cause that produces central visual field loss and is the leading cause of permanent visual impairment in the United States. Contributing factors include a family history of macular degeneration, advancing age, cataract surgery, hyperlipidemia, hypertension, obesity, smoking and a diet low in carotenoids, vitamin C, vitamin E, and zinc. People with Alzheimer disease will eventually develop macular degeneration, but the reverse is not true.
Symptoms: There are two kinds of macular degeneration: wet and dry. In wet MD, neovascularization intrude under the retinal pigment epithelium from the choroid, where the new blood vessels may suddenly bleed or leak fluid, distort the normal architecture of the macula, and degrade central visual acuity. The visual loss caused by wet MD is an emergency. In dry MD, the more common and more benign form, hard and soft druses accumulate beneath the retinal pigment epithelium. They may cause slowly progressive blurring of central vision or may occasionally lead to wet MD.
The central visual loss that marks MD can make reading, working with the hands, driving, or recognizing people’s faces difficult because the center of the visual field is the region of greatest loss of visual acuity, i.e, a central scotoma. Peripheral vision is preserved in this disease.
Treatment includes smoking cessation and antiangiogenic drugs such as vascular endothelial growth factor (VEGF) inhibitors, (eg. ranibizumab, bavacizumab).
What is the macula?
The macula is the specialized central region of the retina that surrounds the fovea and contains a high concentration of cone photoreceptors. It is responsible for central vision, fine visual detail, and color vision. It is located anatomically between the superior and inferior temporal vessels of the retina.
What is metamorphopsia?
Metamorphopsia is distortion of vision, especially of the central visual field.
What are drusen?
Drusen are small, yellow is deposits found between the retinal pigment epithelium and Bruch’s membrane. Drusen accumulate in the retina in “dry” age-related macular degeneration.
What is retinitis pigmentosa?
Retinitis pigmentosa refers to a group of hereditary neurodegenrative retinal disease marked by defective night vision followed by a progressive loss of the field of vision. Rod and cone photoreceptor degeneration is followed by degenerative changes in retinal neurons and the optic blood vessels and nerve head.
What is dystrophy?
Dystrophy is a general term for tissue degeneration such as that caused by disease or nutrition of metabolism.
What is central scotoma?
A scotoma is an island-like blind spot in the visual field. A central scotoma is scotoma of depressed vision involving the point of fixation, seen in lesions of the macula.
What is retinoblastoma?
A malignant glioma of the retina, usually unilateral, that occurs in young children and is usually hereditary. One of hundreds of genetic mutations in the retinoblastoma protein (a tumor regulatory protein) may be responsible. The initial diagnostic finding is usually a yellow or white light reflex seen at the pupil (cat’s eye reflex). Several treatment options are available depending on the size and extent of the tumor, whether both eyes are involved, and the general health of the patient. These options include chemosurgery, intravitreous chemotherapy, cryotherapy, laser photocoagulation, scleral plaque irradiation, and, when other treatments fail, enucleation.
What is leukocoria?
White or abnormal pupillary reflex. This reflex may be present in infants and children who have retinoblastoma, cataract, retinal detachment, and intraocular infections. Patients with this re- flex should be referred to an ophthalmologist without delay.
What is the Edinger-Westphal nucleus?
The Edinger-Westphal nucleus is a nucleus of the visceral motor column in the hindbrain. It lies in the midbrain tegmentum, just beneath the cerebral aqueduct and lateral to the oculomotor nucleus. This nucleus is the origin of preganglionic parasympathetic axons in the oculomotor nerve (CN III); it innervates the ciliary and pupillary constrictor muscles of the eye.
