Derived from Greek word ‘pterygion’ means
It is a non malignant slow growing
proliferation of wing shaped fibrovascular
Arises from subconjunctival tissue.
May extend over the cornea thus disturbing
World wide distribution.
More common in warm and dry climates.
Prevalence : 22% equatorial areas.
<2% in latitudes between
Direct relation with amount of UV exposure.
Sex: male : female= 2:1
Age:>40years high prevalence
20-40years high incidence.
In India prevalence is 9.5%.
Morbidity: causes significant alteration in
visual function in advanced cases.
Strong association between UV light exposure
and formation of pterygium.
More common- in patients who worked
In welders than other factory workers.
Also associated with basal cell
carcinoma, porphyria cutanea
tarda, polymorphous light
eruptions, xeroderma pigmentosa.
ANGIOGENESIS FACTOR:Prolonged UV
exposure causes biological changes in the
Altered protein so formed could act as
angiogenic/ pterygiogenic factor.
UV Exposure: May induce hyperplasia in limbal
cells. These altered cells invade the cornea and
limbus which moves centripetally with them. This
explains wing shape of the pterygium.
UV radiation causes depletion of langerhan cells
at limbus.(stocker’s line).
Exposure to UVB+altered tear film
Injury and susceptibility
Loss of collagenase and dehydration
Accumulation of Extracellular matrix
Antigenic,type1 HS Pinguecula
Light entering the temporal limbus at
90degree is concentrated at medial limbus.
Related to corneal curvature.
This explains the predominance of medial
Dry and dusty environment.
Drying of the tear film by wind devitalizes
tissue of medial 3rd of the palpebral aperture.
This allows the actinic radiation to damage
the conjunctival, corneal epithelium and
MICROTRAUMA: mechanical irritation by dust
particles, enhanced by tear flow from lateral
IMMUNOLOGY: Cell bound IgE irritant
complexes initiate the release of
inflammatory mediators from mast cells.
Release of stimulatory factors.
Development of pterygium.
Expression of vimentin.
P53 mutation leads to decreased apoptosis
and increased TGF-b which leads to increased
RECURRENT PTERYGIUM- stem cells are more
scattered and expression pattern is more
HYPOXIA: increase in non perfusion areas and
attenuated vessels in nasal limbus during
early stage of pterygium causes recruitment
of progenitor cells.
Viral markers: infection with HPV and herpes
virus is considered as risk factor(rare).
Elastotic degeneration of collagen.(Not a true
Fibro vascular proliferation with an overlying
covering of epithelium-characterized by
Subepithelial tissue shows basophilic
Destruction of bowman’s membrane in the
So there is residual corneal scarring when
these growth are removed.
Epithelium shows secondary changes like
Mast cells occur in increased number.
CLINICAL STAGING PATHOLOGICAL
Stage I Exposure Size and number of Altered tear film
conjunctivitis Conjunctival vessels Mild vascular
Mild – moderate congestion response
S/S of dryness
No formed lesions
Stage II Pinguecula Distinct raised lesion on Cell injury
and pterygium bulbar conjunctiva Inflammatory
With or w/o abnormal response
Stage III Limbal pterygium Head is on or across Lesion
the limbus with or w/o organization
an iron line at the
conjunctival corneal Mixed
Vascularization and degeneration
Stage IV Corneal Lesion 2mm or more Lesion b/w
pterygium into cornea epithelium and
Invasion of granulation bowman
Zone of dellen Mixed
Stocker’s line proliferative
Infiltration of corneal and
nerves- pain degeneration
Stage V Compound Induced astigmatism Lesion extended
pterygium Symptoms more into stroma
frequent and severe
Proliferation- Small lymphocytes and plasma cells
Degeneration- Swirls of type I collagen
Primary double pterygium.
pterygium with restriction of ocular
Foreign body sensation
Irritation and grittiness-interference with
precorneal tear film.
Interference with vision-obscuring visual axis
Type 1: extends <2mm on the cornea.
Type 2: 4mm of cornea is involved.
Type 3: encroaches onto >4mm of cornea
and involves visual axis.
Condition Signs and symptoms Tests
Pseudopterygiu Most often hx of -Slit-lamp examination:
m previous infective, reveals lesion to be
chemical, thermal, or adhesion of a fold of
traumatic injury to the conjunctiva, which has
cornea. occurred as a response to
May occur at multiple a previous peripheral
locations and is not corneal
restricted to the 3 and 9 ulcer/inflammation.
o'clock (interpalpebral) -Lesion typically only fixed
positions. at its apex to the cornea
so that a probe may be
passed underneath its
body at the limbus, while a
true pterygium adheres to
the underlying cornea
throughout its length.
Thinning of the underlying
cornea may be seen at its
Pinguecula Does not encroach on Slit-lamp examination:
the cornea. reveals exact extent and
nature of lesion. A
pingueculum is limited to
limbus and conjunctiva
and does not encroach
onto the cornea.
Marginal keratitis Associated with Corneal swab/scraping:
blepharitis. Infiltrate on microscopy and culture
corneal surface is positive for infecting
separated by a clear organism, but infecting
zone from the limbus. organisms are often not
Occur at 2, 4, 8, and detected, as many cases
10 o'clock position. are due to an
Does not have typical inflammatory reaction to
pterygium shape. Often staphylococcal proteins
superior and inferior.
Corneal micropannus Hx of trachoma or lack Slit-lamp examination:
of corneal oxygenation reveals encroachment
due to excessive of fine blood vessels
contact lens wear. onto corneal surface.
Conjunctival Rare. Does not have Slit-lamp examination:
carcinoma in situ/ typical pterygium gelatinous-appearing
bowens epithlioma. shape. Not restricted mass.
to the 3 and 9 o'clock Biopsy: cytological
(interpalpebral) features of a
positions and can squamous cell
occur at any position carcinoma, but the
on the cornea. basal membrane of
Squamous cell Rare. Does not have typical Slit-lamp examination:
carcinoma pterygium shape. Not surface may appear
restricted to the 3 and 9 keratinised and
o'clock (interpalpebral) friable.
positions and can occur at Biopsy: well-
any position on the cornea. differentiated
May arise from a pterygium, squamous cell
carcinoma in situ, or de carcinoma with
novo. invasion of the basal
Limbal dermoid Benign choriostomatous Histology contains
tissue. MC site:inferior abberant tissue like
temporal quadrant. epidermal
Symptomatic patients- Tear substitutes
Inflammation- Topical steroids
Sunglasses- to reduce UV exposure and
decrease growth stimulus
1. Extension to the visual axis and induced
2. Recurrent irritation.
3. Cosmetic- patient should be explained
there is fairly high risk of recurrence, which
may be more unsightly.
Free conjunctival autograft for primary and
Pre op evaluation:
1. Evaluation of pterygium.
2. Evaluation of superior bulbar conjunctiva.
3. Pre op preparation.
4. Anaesthesia and sedation.
Preparation and drape.
Place anaesthetic drops or topical
Ask patient to look opposite side of pterygium.
Goal: Achieve a normal, topographically
smooth ocular surface
Dissect a smooth plane toward the
Preferable to dissect down to bare sclera
Bare sclera = remove loose Tenon’s layer
and leave episcleral vessels intact
Mechanism of action: it acts forming a fibrin
clot between graft and host tissue.
Advantages : decreases the post op pain.
reduces the surgical time as well
as recurrence rate.
Disadvantage : not FDA approved.
Recurrence rate: less as compared to suture.
Avoid exposure to sunlight.
Use of dark sun glasses.
Topical steroid antibiotic drops, topical
NSAIDS, artificial tears.
POD3/5 graft acquires redness.
Complete healing expected between 6-
Topical medications should be tapered.
Lubricants should remain for 3months.
Instruction to patient: avoid exposure to
Bare sclera technique:
Subconjunctival scarring limitation of
Disinsertion of medial rectus muscle.
Corneal irregularity due to deep stromal
Growth of fibrovascular tissue across the limbus
onto cornea after initial removal.
Excludes persistence of deeper corneal vessels
and scarring which may remain even after
Bunching of conjunctiva and formation of
parallel loops of vessels, which aim almost like
an arrowhead at the limbus, usually denotes a
Grade 1 – normal appearing
Grade 2 – fine episcleral
vessels in the site extending
to the limbus.
Grade 3 – additional fibrous
tissues in site.
Grade 4 – actual corneal
AIM: To reduce recurrence.
1. Corticosteroids- post operative use of
topical steroids can reduce inflammatory
reaction and revascularization at the
2. No significant role in prevention of
Antibiotic and antineoplastic properties.
Blocks the DNA synthesis.
Use: intraoperative to the area of resection
with sponge for 2min followed by irrigating
with balanced salt solution.
Side effects: pyogenic granuloma
dellen of sclera.
perforation of eye.
Recurrence: 3-25% (intraoperative)
period LCAG MMC
3 month 1 -
6 month 1 2
12 month - 1
18 month - -
Total 02 (4%) 03 (6%)
Nitrogen mustard alkylating agent.
Radiomimetic- obliterates vascular
Dose:1:2000 every 3 hours for 6 weeks.
Used in bare sclera method.
Complication: scleral thinning.
Inhibits thymidylate synthetase, thus inhibits
Only cells in the synthesis phase are
affected, allowing the remaining cells to
continue to proliferate after exposure to 5-
Dose: 0.05% topical for 3 months following
Safe and effective.
Low recurrence rate(3.4%)
Stop the progression or prevent the
Case reported by Wu and co workers.
Topical bevacizumab eye drops 25mg/ml
4times for 3weeks.
No recurrence in 1year follow up period.
Reduces mitosis in rapidly dividing vascular
Dose : 15Gy units in single or divided doses.
Recurrence: 4.3%-35% with bare sclera or
simple conjunctival closure.
Complications: scleral necrosis
The area of bare scleral was covered with
amniotic membrane, which was oriented with
the basement membrane side up.
The amniotic membrane was sutured
through the episcleral tissue to the edge of
the conjunctiva along the bare sclera border
with 7-8 interrupted 8-0 Vicryl sutures.
The eye was patched.
very large conjunctival defects.
To preserve superior conjunctiva for future
Advantages: faster healing rate
lower recurrence rate(2% in
1year follow up)
Angiostatic steroid: Inhibits the blood vessel’s.
Topical 1% have inhibitory effect on pterygium
regrowth following recurrenr pterygium
Surgical and medical management of
Pterygium-a practical guide to
management,L. Alfred andeze.
Kanski clinical ophthalmology.