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1. PROPTOSIS NISHA SANGROULA INTERN, MBBS OPHTHALMOLOGY

2. INTRODUCTION: Proptosis is abnormal forward displacement of the eyeball beyond the orbital margins, results from wide varietes of the pathologies that can be vision threatening. Generally, a 2 mm or greater asymmetry between the protrusion of a patient’s eyes is considered abnormal.

3. Anatomy of the orbits: The orbits are bony cavities those enclose structures such as the eyeball, extraocular muscles, nerves , blood vessels and a cushion of fat. Pear shaped, tapering posteriorly to the apex. Volume of each orbit is about 30cc, approximately one-fifth of which is occupied by the eyeball.

4. The bony orbit is enclosed by four walls: Medial wall Lateral wall Roof(superior wall) Floor(inferior wall) T he four walls converge at the apex of the orbit. The medial wall is very thin, known as ‘LAMINA PAPYRACEA’.Infection from the ethmoidal sinuses can easily reach the orbit. The lateral wall covers the half of the eyeball , leaving the anterior half exposed on the side.(strongest part) The roof of the orbit is thin and easily damaged by trauma or iatrogenically during surgical procedures. The floor is thin and easily damaged in blow-out fractures of the orbit. Tumors from the maxillary antrum easily invade into the orbit through this pathway.

5. Classification: I.On the basis of eye envolvement : Unilateral proptosis Bilateral proptosis II. On the basis of onset: Acute Subacute Chronic III. Intermittent proptosis IV. Pulsating proptosis

6. DIFFERENTIAL DIAGNOSIS ACCORDING TO LATERALITY: Unilateral Proptosis : CONGENITAL CONDITIONS: ( Dermoid cyst, orbital teratoma , congenital cystic eyeball) INFLAMMATORY CONDITIONS : (Orbital cellulitis , abscess, thrombophlebitis , panohthalmitis , cavernous sinus thrombosis, tuberculoma , gumma ) TRAUMATIC LESIONS: (Orbital hemorrhage, retained intraorbital foreign