A pterygium is a proliferation of fibrovascular tissue on the surface of the eye, which extends onto the cornea. The etiology of pterygium is incompletely understood. However, chronic UV exposure is accepted as a causative agent.

C. Lichen planus

D i.e. Lichen planus

A. i.e. Arise from any part of conjunctiva

Ans. Elastotic degeneration

Pterygium:

• A triangular, fibrovascular growth of degenerative subconjunctival tissue over the-cornea, destroying its Bowman\’s membrane and superficial stroma.
• Histologically, similar to Pinguecula showing elastotic degeneration of the subconjunctival tissue with added vascularization.
• Most commonly seen nasally situated always within the palpebral aperture though it can be present temporally-also known as double pterygium.
• Cause : UV light exposure.

Ans. Arise from any part of conjunctiva

Pterygium:

• It is a subconjunctival fibrovascular tissue encroaching the cornea.
• It is a degenerative condition of the sub-conjunctival tissue.
• It is a connective tissue disorder and is never inflammatory. 

It is made up of three parts:
 a \”cap\” (an avascular halo-like zone at the advancing edge),
 a head,
 a body.

• Occurs due to exposure to radiation: UV-B.
• The most common site is nasal.

Clinical features:
 Astigmatism with the rule, usually
 Stocker\’s line deposition of iron on the advancing edge.
 Fuchs islets are small, discrete, whitish flecks consisting of clusters of pterygial epithelial cells, often present at the advancing edge.

Ans. D: Mitomycin- C

Pterygium/ Surfer\’s Eye

• It most often refers to a benign growth of the conjunctiva.
• A pterygium commonly grows from the nasal side of the sclera.
• It is usually present in the palpebral fissure.

• It is associated with, and thought to be caused by ultraviolet-light exposure (e.g., sunlight), low humidity, and dust.
• Pterygium in the conjunctiva is characterized by elastotic degeneration of collagen (actinic elastosis) and fibrovascular proliferation.
• It has an advancing portion called the head of the pterygium, which is connected to the main body of the pterygium by the neck.

Sometimes a line of iron deposition can be seen adjacent to the head of the pterygium called Stocker\’s line. The location of the line can give an indication of the pattern of growth.

The pterygium is composed of several segments:

–          Fuchs\’ Patches (minute gray blemishes that disperse near the pterygium head)

–          Stocker\’s Line (a brownish line composed of iron deposits)

–          Hood (fibrous nonvascular portion of the pterygium)

–          Head (apex of the pterygium, typically raised and highly vascular)

–          Body (fleshy elevated portion congested with tortuous vessels)

–          Superior Edge (upper edge of the triangular or wing-shaped portion of the pterygium)

–         Inferior Edge (lower edge of the triangular or wing-shaped portion of the ptyerygium). Symptoms of pterygium

• It include persistent redness, inflammation, foreign body sensation, tearing, which can cause bleeding, dry and itchy eyes.
• In advanced cases the pterygium can affect vision as it invades the cornea with the potential of obscuring the optical center of the cornea and inducing astigmatism and corneal scarring

Management

• As it is a benign growth, pterygium typically does not require surgery unless it grows to such an extent that it covers the pupil, obstructing vision or presents with acute symptoms.
• Some of the irritating symptoms can be addressed with artificial tears.
• However, no reliable medical treatment exists to reduce or even prevent pterygium progression.
• Definitive treatment is achieved only by surgical removal.
• Long-term follow up is required as pterygium may recur even after complete surgical correction.
• If there is recurrence after surgery or if recurrence of pterygium is thought to be vision threatening, it is possible to use strontium (90Sr) plaque therapy.
• 90Sr is a radioactive substance that produces beta particles, which penetrate a very short distance into the cornea at the site of the operation.
• Conjunctival auto-grafting is a surgical technique that is effective and safe procedure for pterygium removal.
• Amniotic membrane transplantation with Tisseel glue application and Mitomycin-C has shown excellent cosmetic outcomes with a surface free of redness, stitching, or patches, which makes the ocular surface suitable for vision correction surgery sooner

Ans. is \’a\’ i.e., Astigmatism

Ptervgium

• Pterygium is a non-cancerous (non-neoplastic) growth of conjunctiva, characterized by a wing-shaped fold of conjunctiva encroaching upon the cornea from either side within the interpalpebral fissure. Pterygium is always situated in the palpebral aperture.
• Pathologically Pterygium is a degenerative and hyperplastic condition of conjunctiva. The subconjunctival tissue undergoes elastotic degeneration and proliferates as vascularized granulation tissue under the epithelium, which ultimately encroaches the cornea. The corneal epithelium, Bowman\’s layer and stroma are destroyed.

Etiology & Clinical features

• Pterygium is more common in people with excess outdoor exposure to sunlight (UV rays), dry heat, high wind and abundance of dust. Therefore it is more common in those who work outdoors.
• Clinically it presents as a triangular fold of conjunctiva encroaching the cornea in the area of palpebral aperture, usually on the nasal side. Other findings are stocker\’s line (deposition of iron)
• Ptergyium is an asymptomatic condition in the early stages, except for cosmetic intolerance. Visual disturbance or corneal astigmatism may occur. Visual disturbances are due to encroachment of pterygium on pupillary area or corneal astigmatism. Occasionally diplopia may occur due to limitation of ocular movements.

Treatment

• Asymptomatic pterygium which is not progressive is best left alone. Surgical excision is the only satisfactory treatment and is indicated for : – (1) Cosmetic reasons, (2) Continued progression threatening to encroach onto the pupillary area (once the pterygium has encroached pupillary area, wait till it crosses on the other side), (3) Diplopia due to interference in ocular movement.

Ans. is \’a\’ i.e., Recurrence

Surgical excision of pterygium is its only satisfactory treatment and is indicated for ‑

1. Cosmetic reasons
2. Continued progression threatening to encroach onto the pupillary area (once the pterygium has encroached pupillary area, wait till it crosses on the other side)
3. Diplopia due to interference in ocular movements.

• Recurrence of the pterygium after surgical excision is the most common problem after pterygium excision and is seen in 30 – 50 % of the cases.
• The post-operative complications of pterygium surgery are:

1. Recurrence (most common)
2. Others: Bleeding, corneal thinning, scarring, fornix loss, symblepharon formation, rectus muscle injury, wound dehiscence, Dellen formation, graft chemosis, conjunctival granuloma, epithelial inclusion cysts, astigmatism etc.