OPHTHALMOLOGY

Myopia

Aug 26, 2019 by in OPHTHALMOLOGY Comments Off on Myopia

Definition and prevalence Myopia is the most common human eye disorder in the world. For this refractive state, the retina is located behind the focal plane so that a concave…

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Vasculogenic mimicry

Aug 26, 2019 by in OPHTHALMOLOGY Comments Off on Vasculogenic mimicry

Overview and clinical context By the mid-1980s, many uveal melanoma patients were electing treatment by vision-sparing radiation therapy, avoiding surgical removal of the affected eye (enucleation). The Collaborative Ocular Melanoma…

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Molecular basis of low-penetrance retinoblastoma

Aug 26, 2019 by in OPHTHALMOLOGY Comments Off on Molecular basis of low-penetrance retinoblastoma

Clinical background Retinoblastoma is the most common intraocular malignancy in children and is the prototype inherited cancer predisposition syndrome. About 60% of new patients exhibit unilateral ocular involvement with familial…

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Uveal melanoma

Aug 26, 2019 by in OPHTHALMOLOGY Comments Off on Uveal melanoma

Clinical background Uveal melanoma is a malignant neoplasm that arises from neuroectodermal melanocytes within the choroid, ciliary body, or iris, and it is the most common primary malignant intraocular neoplasm….

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Toxic optic nerve neuropathies

Aug 26, 2019 by in OPHTHALMOLOGY Comments Off on Toxic optic nerve neuropathies

The toxic optic neuropathies (TON) are caused by a widely varied group of insults that may include chemicals, drugs, nutritional defects, and vaccines ( Box 46.1 ). The goal of…

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Nystagmus

Aug 26, 2019 by in OPHTHALMOLOGY Comments Off on Nystagmus

Introduction Nystagmus is defined as a rhythmic oscillation of the eyes. The term “nystagmus” is a transliteration of a Greek word for “drowsy head-nodding movements,” since the jerky eye movements…

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Ischemic optic neuropathy

Aug 26, 2019 by in OPHTHALMOLOGY Comments Off on Ischemic optic neuropathy

Introduction Ischemic optic neuropathy refers to a group of conditions in which damage to the optic nerve is presumed to be secondary to ischemia of the optic nerve head (anterior…

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Optic atrophy

Aug 26, 2019 by in OPHTHALMOLOGY Comments Off on Optic atrophy

Clinical background Optic atrophy can be considered the wasting of a once-healthy optic nerve. This definition excludes conditions associated with optic nerve dysplasia, hypoplasia, or aplasia in which the optic…

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Optic nerve axonal injury

Aug 26, 2019 by in OPHTHALMOLOGY Comments Off on Optic nerve axonal injury

Overview Unlike the peripheral nervous system (PNS), in which axonal injury leads to regeneration, injury to axons of central nervous system (CNS) neurons is irreversible, and usually leads to death…

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Leber’s hereditary optic neuropathy

Aug 26, 2019 by in OPHTHALMOLOGY Comments Off on Leber’s hereditary optic neuropathy

Clinical background Historical development Leber’s hereditary optic neuropathy (LHON) is a maternally inherited disease that presents with sudden or subacute nonsynchronous bilateral vision loss. Males in their second and third…

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