1) DEFINITION Most often refers to a benign growth of conjunctiva It grows from the nasal side of sclera pterygium is a fleshy growth that invades the cornea (the clear front window of the eye). It is an abnormal process in which the conjunctiva (a membrane that covers the white of the eye) grows into the cornea.
2) ETIOLOGY Unknown but may related to : a) Ultraviolet rays (most important factor) -engaging in occupations that require outdoor activity b) Chronic irritation by dust etc c) Genetic predisposition -development of pterygium appear to exist in certain families
Symptoms Persistent rednessInflammationFB sensation Dry eyesItchy eyes Cosmetically disfigurement Potential of induced astigmatism Corneal scarring Vision affected (if it reaches central part of cornea)
Signs APEX : blunt and lies over the cornea and may grow to reach papillary area(affects vision) NECK : Overlies the limbus BASE : Lies over the sclera Site : On the nasal side less commonly temporal and always bilateral Shape : Is triangular and consists of apex, neck & base Site : On the nasal side less commonly temporal and always bilateral Shape : Is triangular and consists of apex, neck & base
Course A) PROGRESSIVEB) STATIONARY Thick and fleshy Vascular Preceded by white dots Thin and membranous Less vascular
5) DIFFERENTIAL DIAGNOSIS A- Neoplasia # carcinoma in situ of conjunctiva and cornea. Also known as Bowen’s disease. # squamous cell carcinoma # other neoplastic diseases B- Pannus C- Pingueculae # commonly occurring, generally small and asymptomatic # occasionally be subject to some inflammation with symptoms of itching, burning, or mild pain # mild-to-moderate focal thickening of the conjunctival stroma with elastotic degeneration of collagen
D.D of Pterygium & Pingueculae Diff.PterygiumPingueculae NatureDegenerative conditionDegenerative condition occuring in old people ShapeTriangular which the apex lies over the cornea Triangular nodule with base towards the cornea ColorReddish white (fibrovascular tissue) Yellow (raised) SiteNasal side Always bilateral Nasal side PathologyConjunctival epithelium (thin layer) + Fibro-vascular tissue + Destroyed: Bowman’s layer & sup. layer of stroma Hyaline degeneration (of conjunctiva) + Elastic tissue deposition
6) TREATMENT Pterygium is best left alone - if small & stationary - recurrence may follow the operation Indications of operations : # progressive # if it encroaches pupillary area # if patient is annoyed (cosmetic reason)
NON SURGICAL 1) Eyedrops for irritation and redness. 2) Protection from sunlight and dust to prevent it from wosening 3) Steroids to lessebn inflammations
Operation for pterygium (1) Excision + bare sclera technique pterygium is removed leaving a raw area of sclera (this allows corneal epithelium to cover the cornea before conjunctival epithelium reaches the limbus) (2) Excision + application mucous membrane,conjunctival or coeneal graft - gap in the mucous membrane (conjunctiva) tissue, where the pterygium was removed, is filled with a transplant of tissue that has been painlessly removed from underneath the upper eyelid.
PREVENTION OF PTERYGIUM Wearing protective sunglasses with side shields and/or wide brimmed hats (as it is associated with excessive sun or wind exposure) Using artificial tears (prevent their formation/stop further growth Surfers & water-sport athletes: - wear eye protection (block 100% of UVR from water)
MEASURES USED TO PREVENT RECURRENCE : Expose the bare area to Beta irradiation. Expose the bare area to Mytocin C Excision & mucous membrane grat. Excixion & lamellar (structural) keratoplasty Stem cell transplantation