Pterygium

Definition

Triangular wing
shaped encroachment of the conjunctiva onto the cornea usually on the nasal
side.

Etiology:

Common in
sunny, dusty, sandy climate.

Highly correlated with UV Sunlight Exposure.

Nasal
pterygium is more common than temporal because Light entering the temporal
limbus at 90 degree is concentrated at medial limbus.

Pathology:

Vermiform
or elastotic degeneration of subepithelial tissue. Typical feature is destruction
of Bowman layer by fibrovascular ingrowth.

Symptoms:

Irritation, foreign body sensation, watering, blurring of vision.

Signs:

A pterygium
has four parts: (i) Apex (ii) cap (iii) neck, and (iv)a bulbar portion
extending between the limbus and the canthus, body.

Classification:

• Progressive: thick, fleshy, vascular,
  progressively encroaching towards the center of the cornea.
• Atrophic: Thin, attenuated, poor vascularity,
  stationary.

Stocker’s line represents deposition of iron in the corneal epithelium
anterior to the head of the pterygium.

Grading:

Grade
I: pterygium between the limbus and a point midway between the limbus and the
pupillary margin (temporal pupillary margin for temporal pterygium, and nasal
pupillary margin for nasal pterygium)

Grade
II: head of the pterygium is present between a point midway between the limbus
and the pupillary margin

Grade
III: pterygium that crosses the pupillary margin

 

Treatment:

Medical
treatment with Lubricants and decongestant drops. Topical steroids can be given
for short time period in tapering doses.

Surgical
treatment:

Exicision
of conjunctiva with autograft, amniotic graft, bare sclera technique can be
done. High incidence of recurrence was noted with bare sclera technique.
Adjunct therapy with Cautery, laser therapy, mitomycin c, Thiotepa, 5 fluorouracil,
Anti-VEGF, beta radiation

Complications:

Recurrence, Corneal scarring,
perforation, Strabismus.

Differential diagnosis:

Psuedopterygium, Limbal dermoid,
pingecula, nodular episcleritis, Phlycten, Conjunctival carcinoma in situ, Ocular
surface squamous neoplasia (OSSN).

 

About the Author

Dr. Pilli Nishita, MBBS, MS in Ophthalmology, is currently a fellow in Medical Retina and is pursuing a Glaucoma fellowship at Aravind Eye Hospital in Coimbatore. With a robust academic and clinical background, Dr. Nishita specializes in diagnosing and treating various eye conditions, focusing extensively on retinal and glaucoma care. Her expertise extends into conducting and participating in multiple research studies aimed at advancing the understanding and treatment of eye diseases.

 

 

 

 

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