Items tagged “eye”
68 results found
Article
Abducens nerve
The abducens nerve is the sixth cranial nerve (CN VI). It is a motor nerve responsible for abduction of the eye (TA: nervus abducens or nervus cranialis VI). It courses from the abducens nucleus, located in the dorsal pons, up to the cavernous sinus, via a long cisternal segment that is prone to...
Article
Calcification of the globe (differential)
Calcification of the globe has many causes, varying from benign to malignant. When calcification is seen in the posterior half of the globe, it could relate to any of the layers (scleral, choroidal or retinal), as it is not possible to separate them out on CT.
Retinal
drusen: 1% population at ...
Article
Ectopia lentis
Ectopia lentis refers to subluxation or dislocation of the lens of the eye secondary to dysfunction or disruption of zonular fibers. It is most commonly due to trauma. The commonest atraumatic etiologies are Marfan syndrome and homocystinuria.
Pathology
Etiology
trauma
systemic and syndromic...
Article
Orbit
The orbits are two bony sockets at the front of the face that primarily house and protect the eyes and associated structures.
Terminology
Ocular or optic refers specifically to the globe (eyeball). Orbital refers to all the contents of the bony orbit, encompassing both the intra and extraocul...
Article
Idiopathic orbital inflammation
Idiopathic orbital inflammation, also known as orbital pseudotumor and non-specific orbital inflammation, is an idiopathic inflammatory condition that most commonly involves the extraocular muscles. Less commonly there is inflammatory change involving the uvea, sclera, lacrimal gland, and retrob...
Article
Retinal detachment
Retinal detachment is a detachment of the neurosensory retina from the underlying pigmented choroid. Apposition of the retinal pigmented epithelium to the overlying retina is essential for normal retinal function.
Terminology
There are numerous subtypes of retinal detachment 5:
rhegmatogenous...
Article
Retinoblastoma
Retinoblastomas are the most common intraocular neoplasm found in childhood and with modern treatment modalities, are, in most cases, curable.
On imaging, they are generally characterized by a heterogeneous retinal mass with calcifications, necrotic components and increased vascularization on D...
Article
Superior orbital fissure
The superior orbital fissure is the communication between the cavernous sinus and the apex of the orbit. It is straddled by the tendinous ring which is the common origin of the four rectus muscles (extraocular muscles).
Gross anatomy
Boundaries
medial: body of sphenoid
superior: lesser wing ...
Article
Tendinous ring
The tendinous ring, also known as the annulus of Zinn, is the common origin of the four rectus muscles (extraocular muscles).
The tendinous ring straddles the lower, medial part of the superior orbital fissure. It attaches to a tubercle on the greater wing of the sphenoid bone (at the margin of...
Article
Ophthalmic artery
The ophthalmic artery is a branch of the supraclinoid (C6) segment of the internal carotid artery.
Gross anatomy
Origin
The ophthalmic artery arises medial to the anterior clinoid process as the internal carotid artery exits the cavernous sinus. It originates from the antero- or supero-medial...
Article
Leukocoria
Leukocoria (also spelled as leucocoria or leukokoria) refers to an abnormal white reflection from the retina of the eye. Despite its color, the reflection is related to the familiar red-eye effect. Usually, when a light is shone through the iris, the retina appears red to the observer. In leukoc...
Article
Coloboma
Coloboma is a collective term encompassing any focal discontinuity in the structure of the eye and should not be confused with staphylomas which are due to choroidal thinning.
Terminology
While coloboma is the collective term for any focal discontinuity in the eye's structure, many people use...
Article
Trilateral retinoblastoma
Trilateral retinoblastoma refers to the combination of retinoblastoma (usually bilateral) and pineoblastoma. This relationship highlights the close relationship between these highly aggressive small round blue cell tumors.
It affects only a minority of patients with retinoblastoma (1.5-5%) and ...
Article
Optic pathway glioma
Optic pathway gliomas are relatively uncommon tumors, with a variable clinical course and usually seen in the setting of neurofibromatosis type I (NF1). Histologically the majority are pilocytic astrocytomas.
They are characterized by imaging by an enlarged optic nerve seen either on CT or MRI....
Article
Tram-track sign (orbit)
Tram-track sign refers to the parallel thickening and enhancement around the optic nerve, and is most frequently seen in the setting of optic nerve meningioma. It may, however, also be seen in 1:
orbital pseudotumor
perioptic neuritis
orbital sarcoidosis
orbital leukemia
orbital lymphoma
o...
Article
Morning glory syndrome (eye)
Morning glory disc anomaly (MGDA), also known as morning glory syndrome, is a rare congenital malformation of the optic nerve which is frequently associated with midline abnormalities of the brain and skull 1.
Epidemiology
Morning glory disc anomaly is rare and is more commonly found in female...
Article
Exudative retinitis
Exudative retinitis, also known as retinal telangiectasis or Coats disease, is a rare congenital disease affecting the eyes and is a cause of leukocoria.
Epidemiology
It occurs predominantly in young males, with the onset of symptoms generally appearing in the first decade of life with a peak ...
Article
Optic disc drusen
Optic disc drusen (ODD), or hyaline bodies, are a relatively common entity usually found incidentally on CT or on follow-up of abnormal fundoscopy.
Epidemiology
Optic disc drusen are identified radiographically in up to 0.3-3.7% of the population and are frequently bilateral 1,4,5. They are ty...
Article
Choroidal osteoma
Choroidal osteomas are rare benign calcific masses of the globe.
Epidemiology
Choroidal osteomas are typically found in young Caucasian women 1. A number of familial cases have been reported 3.
Clinical presentation
These lesions are usually unilateral (75%), and result in painless and gra...
Article
Retinoblastoma (staging)
Retinoblastoma staging can be via a number of systems with various end-points and multiple systems are often used concurrently.
Staging
Reese Ellsworth classification
The Reese Ellsworth classification is assessed with fundoscopy and aims at predicting the chance of preserving the eye with ex...