Orbital metastases.

Background: Orbital metastasis, although uncommon, is a condition optometrists should consider in a patient presenting with proptosis, ptosis, diplopia, or a lid mass with a history of cancer. However, in as many as 19% of cases, patients have no prior or concurrent history of systemic cancer when presenting with ophthalmic symptoms. If suspecting an orbital metastasis, neuroimaging is important, as well as a referral to the patient's primary care provider, oncologist, and ophthalmologist.

Palinopsia.

Background: Palinopsia is a visual phenomenon that has been associated with brain neoplasia, epilepsy, trauma, systemic disease, psychiatric illness, and illicit as well as prescribed drug use. Despite some resemblance to diplopia, polyopia, and physiologic afterimage formation, palinopsia is actually a distinct entity often suggestive of disease through its distinct signs and symptoms. Careful patient history, visual field testing, and neuroimaging are among the tools used to diagnose palinopsia.

On the frontline: what an optometrist needs to know about myasthenia gravis.

Background: Myasthenia gravis (MG) is an autoimmune disease that affects the voluntary skeletal muscles. It is characterized by transient weakness of the muscles that improves with rest. Muscle weakness involving the eyes can produce signs or symptoms of diplopia, blurred vision, ptosis, and ophthalmoplegia.

Functional vision loss: a diagnosis of exclusion.

Background: Most cases of visual acuity or visual field loss can be attributed to ocular pathology or ocular manifestations of systemic pathology. They can also occasionally be attributed to nonpathologic processes or malingering. Functional vision loss is any decrease in vision the origin of which cannot be attributed to a pathologic or structural abnormality.

Peripheral retinal neovascularization in talc retinopathy.

Background: Neovascularization of the peripheral retina can be present in a number of systemic and ocular diseases. Very rarely, peripheral retinal neovascularization can also be manifested in intravenous drug abusers. In addition to ocular complications, intravenous drug abusers are at high risk for contracting various infections and the development of pulmonary and cardiovascular diseases.

Sectoranopia: a stroke in the lateral geniculate nucleus or optic radiations?

Background: The lateral geniculate nucleus (LGN) is the site at which ganglion cell axons of the optic tract synapse with neurons that form the optic radiations. Lesions of the perigeniculate visual pathway are characterized by distinct pupillary, visual field, and ophthalmoscopic findings. Such findings, combined with results from neuroimaging, enable one to precisely locate the area of the visual pathway that is involved.

Subclavian steal syndrome.

Background: Subclavian steal syndrome is a systemic entity that is well-documented in the medical literature. It occurs when the subclavian artery becomes stenosed or occluded and blood flow is reversed in the ipsilateral vertebral artery. This siphoning or "stealing" of blood has traditionally been thought to cause symptoms of vertebral-basilar insufficiency.

Coloboma of the crystalline lens.

Background: Anomalies of crystalline lens shape and position include: lenticonus, lentiglobus, microspherophakia, coloboma, and ectopia lentis. Lens coloboma probably results from a localized absence or maldevelopment of lens zonules. It may be a variant of nontraumatic (congenital) ectopia lentis, in which the zonular deficiency is more generalized.

Acquired Horner's syndrome: clinical review.

Background: Horner's syndrome results from disruption of the sympathetic innervation to the eye anywhere along its three-neuron circuit. It is essential to be familiar with the oculosympathetic pathway, the structures that are in close proximity to it, and the disease processes that may interrupt it when an evaluation is made of an acquired Horner's syndrome, since it may be a manifestation of a life-threatening condition.

Case Reports And Discussion: Four patients with acquired Horner's syndrome resulting from various etiologies are presented.

Parieto-occipital arteriovenous malformation.

Background: Arteriovenous malformation (AVM) in the occipital lobe has been known to cause visual symptoms and headaches. Arteriovenous malformation is a congenital anomaly that consists of abnormal arteries and veins without the presence of a capillary bed. The majority of patients initially manifest intracranial hemorrhage, while others manifest symptoms of seizures, headaches, and progressive neurological deficits.