Visual field defects

Nerve fiber defects Visual field findings... 

Patients may also suffer from dysarthria, visual field defects, and altered levels of consciousness. 

Patients usually have multiple signs of neurologic dysfunction on physical examination. The specific deficits observed depend upon the area of the brain involved. Hemi- or monoparesis and hemisensory deficits are common. Patients with posterior circulation involvement may present with vertigo and diplopia. Anterior circulation strokes commonly result in aphasia. Patients may also experience dysarthria, visual field defects, and altered levels of consciousness. 

Most patients with pituitary failure (secondary hypothyroidism) have clinical signs of generalized pituitary insufficiency such as abnormal menses and decreased libido, or evidence of a pituitary adenoma such as visual field defects, galactorrhea, or acromegaloid features. 

Treatment is indicated for all patients with elevated IOP and characteristic optic disk changes or visual field defects. 

Ocular complications following local or systemic administration of steroids include glaucoma, cataracts, adverse influence on specific ocular infections, pseudotumor cerebri, ptosis, mydriasis, subjective visual complaints, visual field defects, systemic absorption of the topical medication, conjunctival and palpebral petechiae, epithelial punctate keratitis, and, possibly, corneal and scleromalacia. ... 

EthambutoL The cause of its specific antitubercular action is unknown. Ethambutol is given orally. It is generally well tolerated, but may cause dose-dependent damage to the optic nerve with disturbances of vision (red/green blindness, visual field defects). 

Special senses Tinnitus diplopia taste perversion amblyopia deafness visual field defect eye pain conjunctivitis photophobia hyperacusis mydriasis parosmia ear pain taste loss. 

Visual field defects - Central scotoma with decreased visual acuity field constriction (rare) pericentral or paracentral scotoma. 

While physicians may not recognize up to 80% of lacunes (Tuszynski et al. 1989), several clinical syndromes have been correlated with relevant lacunes detected at subsequent autopsy. Five of these are regarded as the classic lacunar syndromes pure motor hemiparesis, sensorimotor stroke, pure sensory hemiparesis, dysarthria clumsy hand syndrome, and ataxic hemiparesis (Donnan et al. 2002 Fisher 1982 Bamford 2001). Pure motor stroke is the commonest lacunar syndrome in clinical practice, while pure sensory stroke is encountered less frequently. The involvement of the face, arm and leg of one side is the characteristic feature of the first three syndromes while reductions of consciousness, cognitive or visual field defects are absent. Even though lacunar infarcts have been linked to lacunar syndromes, the latter are of course not specific for this stroke subtype and mimicked by cortical infarcts, intracerebral hematomas, and non-vascular causes (Bogousslavsky et al. 1988 Bamford 2001). 

Bogousslavsky et al. 1988). Posterior choroidal artery infarcts result in visual field defects, variable sensory loss, hemiparesis, dystonia, hand tremor and occasionally amnesia and aphasia. Visual field defects, commonly quadrantanopia or hemianopia, are found if the lateral posterior choroidal arteries branches are involved in isolation. Unusual field defects such as homonymous horizontal sec-toranopia or wedge shaped homonymous hemianopia, may also be found and may be explained by the dual blood supply to the lateral geniculate body by... 

There has been a report of retinal changes in 60 users of crack (164). Microtalc retinopathy and retinal nerve fiber layer rake or slit defects were detected by threshold visual field testing and fundus photography. 

Cognitive or visual field defects may have to be assumed in drowsy patients. Deviation of the eyes towards the affected hemisphere is common but recovers in a few days. A large hematoma may cause midUne shift, transtentorial herniation and coma within 24-hours (Fig. 9.3). By contrast, these changes take two or three days to evolve with large infarcts as cerebral edema develops. 

Lacunar syndromes are defined clinically. They are highly predictive of small, deep lesions affecting the motor and/or sensory pathways in the corona radiata, internal capsule, thalamus, cerebral peduncle or pons. Although a few patients have a partial anterior circulation infarct (Bamford et al. 1987 Anzalone and Landi 1989 Arboix et al. 2007), the great majority have small iirfarcts, which are sometimes visible on CT, more often on MRI. These are caused by presumed occlusion of a small perforating artery affected by intracranial small vessel disease (see Fig. 10.2). There is no visual field defect, no new cortical... 

MS), which is a demyelinating disorder. When optic neuritis occurs without disc swelling, the condition is called retrobulbar neuritis. When disc swelling is associated with optic neuritis, the condition is called papillitis. Papilledema is bilateral disc edema associated with increased intracranial pressure OCP). Optic atrophy, the end stage of many optic neuropathies, is characterized by a pale disc and associated with a relative afferent pupillary defect (RAPD) and possible loss of visual acuity, color vision, and visual field. One example of disc atrophy occurs in cases of Leber s hereditary optic neuropathy... 

In infiltrative optic neuropathy, substances that are not normal to the optic nerve or nerve sheath accumulate within the optic nerve.This diffusion of material results in optic nerve dysfunction. Clinically, the loss of optic nerve function may result in loss of visual acuity, visual field defects, color vision defects, and RAPD. In some cases the optic disc is swollen because of infiltration of the prelam-inar or immediate retrolaminar region. An absence of disc swelling, with visual acuity loss, may occur secondary to infiltration of the retrolaminar portion of the nerve, which causes a retrobulbar optic neuropathy. 

Lymphoma, a neoplastic malignant disorder of the lymphoid tissue, is the most common malignancy that infiltrates the optic nerve. Lymphomatous cells infiltrate the retrolaminar portion of the nerve, leading to a progressive painless loss of visual acuity, color and visual field defects, and RAPD.The disc is often swollen. 

The primary optic nerve tumor that originates within the optic nerve is glioma. Affected patients often present with reduced visual acuity, visual field defects, transient visual obscurations, and disc edema. 

SLE appears to be steroid responsive only in the early coiu se of the disease. Optic atrophy occiu s in untreated cases, with the development of permanent visual field defects. Therapy includes high-dose intravenous methyl-prednisolone, oral prednisone, or steroid-sparing medications such as mycophenolate mofetil (CellCept). A rheumatology referral is also advised. 

Acquired immunodeficiency renders a host much more susceptible to secondary infections, including cytomegalovirus, syphilis, herpes zoster, fungi, hepatitis B, tuberculosis, and toxoplasmosis. HIV invades the tissues of the optic nerve and initiates an immune complex-mediated response that results in an optic neittopathy. The primary HIV infection may be responsible for color vision defects, loss of contrast sensitivity, and visual field defects. HIV infection itself may also cause direct degeneration of retinal ganglion cell axons in the optic nerve without a secondary opportunistic infection. 

During an acute imilateral attack, pupil testing reveals RAPD, because demyelinating disease can disrupt the impulses traveling within the pupillary fibers of the light reflex pathway. Color vision is reduced in most cases. Contrast sensitivity is reduced in cases of MS and may remain reduced after visual recovery occms. The ONTT reported that diffuse visual field loss occurred in 48.2% of eyes and that altitudinal field defects or other nerve fiber bimdle-type defects were present in 20.1% of eyes. Significantly, there was asymptomatic visual field involvement in the fellow eye in 68.8% of patients. 

---