The Orbit

Anatomy: The Roof: frontal bone, lesser wing of sphenoid The Lateral wall: zygomatic, greater wing of sphenoid The floor: maxillary, zygomatic, palatine The medial wall: maxillary, lacrimal, ethmoid, sphenoid.

Functions: Protection to the eye ball Provide attachments to the ligaments which stabilize the eye ball

Clinical features of orbital lesions 1- Soft tissue involvement periorbital oedema,, chemosis (oedema of the conjunctiva) and epibulbar injection Inflammatory or infective conditions

2- Abnormal Displacement of The Eye Ball Proptosis, Enophthalmos;

Clinical features of orbital lesions Abnormal Displacement of The Eye Ball Proptosis Abnormal protrusion of the eye ball Distance between lateral orbital rim and the apex of the cornea is more than 20mm, or difference of 2mm between the two eyes is suspicious. Axial proptosis; axial displacement of the eye ball space occupying lesion inside the muscle cone Optic nerve glioma Thyroid dysfunction: Exophthalmus Eccentric proptosis; non-axial displacement of the eye ball space occupying lesion outside the muscle cone Tumors of the lacrimal gland

Enophthalmos; Backward displacement of the eye ball Blowout orbital fracture

3 -Ophthalmoplegia: impairment of extraocular movement Inflammation (myositis), Fibrosis (thyroid dysfunction), Tethering of the muscles (blow out fractures), Paralysis (ocular motor nerves lesions).

4 - Impairment of Vision 1- Exposure keratopathy secondary to proptosis 2-Optic nerve dysfunction Impairment of vision, diminished pupillary light reflex acute stage; optic nerve congestion, swollen chronic stage; secondary optic disc atrophy

Investigations X-ray C.T. scan MRI

Orbital Cellulitis Vision threatening and can be life threatening condition Infection of the soft tissue of the orbit mostly by bacteria Strep. pneumoniae, Staph. aureus, H. influenzae. Causes; 1-spread of microorganisms from the adjacent structures, paranasal sinuses 2-Post traumatic

Orbital Cellulitis Symptoms Rapid onset Fever, malaise Pain Impairment of vision

Clinical features: Signs Lid swelling, Conjunctival congestion Ophthalmoplegia Proptosis Optic nerve dysfunction

Complications; Cavernous sinus thrombosis Orbital abscess Brain abscess

Management Hospital admission Antibiotic therapy; started immediately with broad spectrum antibiotics Third generation Cephalosporins+ metronidazole

Dysthyroid Ophthalmopathy Autoimmune disorder usually associated with abnormal thyroid function Pathogenesis; Hypertrophy of extraocular muscles Deposition of glycosaminoglycans Infiltration with mononuclear cells, macrophage

Clinical features 1-Conjunctival hyperemia and edema 2-Exophthalmus; most common cause of unilateral and bilateral proptosis 3-Ophthalmoplegia 4- Lid retraction 5-Lid lag 6-Optic nerve neuropathy

Blowout orbital fracture Caused by a sudden increase in the orbital pressure by an impacting object which is greater in diameter than the orbital aperture (about 5 cm), the fracture most frequently involves the floor of the orbit with herniation of the orbital contents

Blowout orbital fracture Enopthalmus Impairment of eye movements

Orbital Tumors Dermoid Benign cystic teratoma, Growth of displaced ectodermal tissue at subcutaneous location Presentation: during infancy Painless nodule at the upper temporal or upper nasal angle of the orbit Firm non tender, smooth surface, freely mobile under the skin

Orbital Tumors Capillary haemangioma Most common benign tumor of the orbit. Vascular hamartoma Presentation: during perinatal period Location: Skin, Strawberry naves on the eyelid, conjunctiva, orbit causing proptosis Course; 70% spontaneous resolution at age 7 years. Treatment; for large lesions, local injection of steroids

Orbital Tumors Optic nerve glioma Meningioma Lacrimal gland tumors Rhabdomyosarcoma; commonest orbital tumor in children

Carotid-cavernous fistula: Abnormal communication between internal carotid artery and cavernous sinus Causes; rupture congenital aneurysm or post traumatic Clinical features; Congested vessels, Chemosis, Hyperemic disc, Pulsating exophthalmus