-IBIS-1.5.0-
tx
eyes/ears/nose/throat
visual disturbances
diagnoses

definition and etiology

definition: Any type of abnormal visual problem.

etiology: There are many types of visual disturbances:

• Spots (floaters): These are a common adult complaint. The spots are a result of vitreous debris from the degeneration of the membranous attachment of the vitreous body to the optic nerve and retina early in life. The spots are worse in bright light and with Valsalva straining. Although potentially bothersome, they are without pathological significance.

• Retinal detachment: Usually from trauma to the head or eye, it is typically preceded by a shower of sparks in one quadrant of the visual field, followed by the sensation of a curtain falling over the the eye. Also manifest as a degenerative problem with aging.

• Scotomas: A (-) scotoma is a blind spot in the visual field. It can often be unnoticed by the patient unless it occurs in the central vision. A (+) scotoma is described as a light spot or scintillating flash and occurs as a response to abnormal stimulation of some portion of the visual system (e.g. during a migraine prodrome).

• Myopia (nearsightedness): This occurs as the visual image strikes in front of the retina due to an elongated eyeball or excessive refractive power. The patient can see near objects but not far ones.

• Hyperopia (farsightedness): This occurs as the visual image strikes behind the retina due to a shortened eyeball or weak refractive power. It is the most common refractive error, and permits patients to see far objects but not objects that are near. Presbyopia is a hyperopia that occurs with advancing age as the lens becomes less pliable.

• Astigmatism: refraction of the eyeball is unequal in its different meridians.

• Anisometropia: a different refractive error in each eye.

• Strabismus (cross-eyes): deviation of one eye from parallel view. If the condition is congenital, there is no diplopia, as the vision in the deviated eye is suppressed by the brain. This suppression results in amblyopia, which is reduced visual acuity.

• Diplopia (double-vision): This can occur for a variety of reasons. It is often seen in acute ophthalmoplegia and extraocular muscle palsies.

signs and symptoms

• vary with the condition; some may be accompanied by signs and symptoms of an underlying disorder

course and prognosis

Refractive errors and astigmatism are treated with either corrective lenses or eye exercises to compensate. In almost all cases but the most severe (those who are considered "legally blind"), 20/20 vision can be recovered. Spots are not treatable with conventional medicine. Strabismus, if caught early, is correctable.

Retinal detachment is a medical emergency as prompt surgery markedly improves prognosis.

differential diagnosis

• need to differentiate cause


footnotes