Update on Pterygium Therapy
Jay C. Bradley, MD
David L. McCartney, MD
January Grand Rounds
From the BCSC: Basics
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Often bilateral
 Almost always situated at the nasal or temporal
limbus within palpebral fissure
 Associated with prolonged UV exposure
UV-B  limbal stem cell p53 mutation   apoptosis /  TGF-   growth
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May be associated with dryness, inflammation,
and exposure to wind and dust or other irritants
 Prevalence increases with proximity to equator
 Difficult to determine if race is independent risk
factor due to confounding variables
Albedo Hypothesis
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Researcher: MT Coroneo (Australia)
Pterygia occur secondary to albedo concentration
in the anterior eye
Light entering the temporal limbus at 90 degrees is
concentrated onto the medial limbus
Related to corneal curvature
Explains predominance of medial pterygia
Ophthalmic surg. 1990 Jan;21(1):60-6.
From BCSC: Basics
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Encroaches on cornea in wing-like fashion
Overlying epithelium often thinned, but can be
hyperplastic or dysplastic
Nearly always preceded by pingueculae
Induces astigmatism (usually “with-the-rule”)
proportional to size
Excision indicated if persistent irritation, vision
distortion, significant (> 3-4 mm) and progressive
growth toward visual axis, restricted ocular
motility, and atypical appearance
From the BCSC: Basics
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Elastotic degeneration – fragmentation and
breakdown of stromal collagen
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Destruction of Bowman’s layer by advancing
fibrovascular tissue resulting in corneal scarring
From BCSC: Basics
Recurrent pterygia – lack elastotic degeneration
and are more accurately classified as an exuberant
granulation tissue response
 Stocker’s line – a pigmented iron line in advance
of pterygium
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Pterygium Excision
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Goal: Achieve a normal, topographically smooth
ocular surface
Dissect a smooth plane toward the limbus
Some surgeons prefer specialized blunt pterygium
blades (Tooke or Gills) while others prefer sharp
blades
Preferable to dissect down to bare sclera at limbus
Bare sclera = remove loose Tenon’s layer and
leave episcleral vessels intact
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Some surgeons avoid medial dissection to avoid
bleeding from trauma to adjacent muscle tissue
while other remove excessive fibrovascular tissue
medially
 Light thermal cautery is applied for hemostasis
Pterygium Recurrence
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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 adequate
removal
 Bunching of conjunctiva and formation of parallel
loops of vessels, which aim almost like an
arrowhead at the limbus, usually denotes a
conjunctival recurrence
Proposed Recurrence Grading
System
Grade 1 – normal appearing
operative site
 Grade 2 – fine episcleral
vessels in the site extending
to the limbus
 Grade 3 – additional fibrous
tissues in site
 Grade 4 – actual corneal
recurrence
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Wound Closure Options:
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Bare sclera
 Simple closure
 Sliding flap
 Rotational flap
 Conjunctival graft
Bare Sclera Closure
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No sutures or fine, absorbable
sutures used to appose
conjunctiva to superficial
sclera in front of rectus
tendon insertion
 Leaves area of “bare sclera”
 Relatively high recurrence
rate with variable techniques
of 5 – 68 % with primary / 35
– 82 % with recurrent)
Simple Closure
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Free edges of conjunctiva
secured together
Effective only if defect is very
small
Can be used for pingueculae
removal
Reported recurrence rates
from 45 – 69 % (one report of
“barest” sclera, N=800 of 2 %)
Few complications (dellen)
Sliding Flap Closure
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An L-shaped incision is made
adjacent to the wound to allow
conjunctival flap to slide into
place
 Reported recurrence rates from
0.75 – 5.6 % (poorly designed,
retrospective)
 Few complications (flap
retraction / cyst formation)
Rotational Flap Closure
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A U-shaped incision is made
adjacent to the wound to form
tongue of conjunctiva that is
rotated into place
 Reported recurrence of 4 %
 Few complications
Conjunctival Graft Closure
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A free graft, usually from
superior bulbar conjunctiva,
is excised to correspond to
wound and is then moved
and sutured into place
 Can be performed with
inferior conjunctiva to
preserve superior
conjunctiva
Conjunctival Graft Closure
Harvested tissue should be approximately 0.5 – 1
mm larger than defect
 Most important aspect in harvesting is to procure
conjunctival tissue with only minimal or no
Tenon’s included
 Graft is transferred to recipient bed and secured
with or without incorporating episclera
 Some surgeons harvest limbal stem cells along
with graft and orient graft to place stem cells
adjacent to site of corneal lesion excision
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Conjunctival Graft Closure
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Topical antibiotic-corticosteroid ointment used for
4 – 6 weeks post-operatively until inflammation
subsides (compliance with this regimen decreases
recurrence)
 Used when extensive damage or destruction of
limbal epithelial stem cells is NOT present
 Reduces recurrence to 2 – 5 % (up to 40 % in
some reports)
 Ameliorates the restriction of extraocular muscle
function
Limbal Conjunctival Autograft
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Reported recurrence rates are variable (between 0
– 40 %)
 Few complications
 Further prospective studies in primary and
recurrent pterygia are needed
Lamellar Corneal Transplant
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Wound closed with piece of lamellar sclera or
cornea
Reported recurrence rates of 6 – 30 %
Not performed often
Can be used in conjunction with AMT for multiply
recurrent pterygia with corneal scarring and
limited available conjunctiva
Method involves increased surgical complexity,
the requirement of donor tissue, and risk of
infectious disease transmission
Adjunctive Beta Irradiation
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Most common dosage is 15 Gy in single or
divided doses
 Reasonably acceptable recurrence rates
(from 0 – 50 % with bare sclera or simple
conj closure)
 Risk of corneal or scleral necrosis and
endophthalmitis
Adjunctive Thiotepa
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Most common dose is 1:2000 thiotepa given
up to every 3 hours for approx. 6 weeks
 Usually used with bare sclera method
 Low reported recurrence rates of 0 – 16 %
(poor study quality)
 Minimal complications (2 cases of scleral
thinning)
Adjunctive Mitomycin C
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Used with bare sclera or conj closure
Most common dose is 0.02 % applied for 3 min
during surgery
Risk of aseptic scleral necrosis / perforation and
infectious sclerokeratitis
Used more often for recurrent cases
Rate of recurrence between 3 – 25 % for intra-op /
5 – 54 % for post-op with most studies showing <
10 % recurrence
Amniotic Membrane Graft
Closure
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Useful for very large conjunctival
defects as in primary doubleheaded pterygium or to preserve
superior conjunctiva for future
glaucoma surgeries
 Requires costly donor tissue
 Reported recurrence rate between
3 – 64 % for primary cases and 0 –
37.5 % for recurrent cases
Other Methods:
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Pterygium head transplantation
Split skin grafts
Ruthenium adjunctive therapy
Laser or thermal cautery
Excimer laser treatment
PDT (one report, N = 10)
Intraoperative doxorubicin / daunorubicin
5-FU
Serum-free derived cultivated conjunctival graft
Recombinant epidermal growth factor
****Few studies with limited numbers of
patients, poor follow-up, and variable
recurrence rates
Primary Pterygium
Metanalysis
Includes 5 studies with N=290 (BS+Mito=257/CAG=33)
Comparison
Bare sclera: mito C
Bare sclera: CAG
Odds Ratio
95 % CI
25:1
6:1
9.0 – 66.7
1.8 – 18.8
Sanchez-Thorin JC et al. Br J Ophthalmol 82:661-5, 1998.
Conclusions:
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There is no clear-cut superior single treatment
Bare scleral and simple conjunctival closure without
adjunctive therapy have relatively high but variable
recurrence rates
Use of beta irradiation and antimetabolites can be
used with appropriate caution
Conjunctival transplants and flaps appear to have
overall lower rate of recurrence but require more
surgical time and unnecessary conj destruction
Other treatment options need further adequate study
prior to widespread implementation
Any Questions?