pterygium and its management with conjuctival autograft

1. Pterygium and its management
Dr Jyoti Prakash Behera

2. Anatomy of conjunctiva

3. Histology of normal conjunctiva

4. Pterygium- Definition
• Derived from Greek word “Pterygos” means
small wing
• It is a non malignant slow growing
proliferation of wing shaped fibrovascular
tissue.
• Arises from subconjunctival tissue.
• May extend over the cornea thus disturbing
the vision.

5. Pterygium- Incidence & Prevalence
• Cameron's map- Shows a direct relationship
between prevalence and proximity to the
equator(warm and dry climate)
• Factors other than geographic location
– Male : female= 2:1
– more common in farmers than in city dwellers
– more who do not wear eyeglasses
– elderly have the highest prevalence rate, but a much
younger (20-to 40-year old) group has the highest
incidence rate

6. • In India prevalence is 9.5%.
• Morbidity: causes significant alteration in
visual function in advanced cases.

7. ETIOPATHOGENESIS.
• Strong association between UV light exposure
and formation of pterygium.
– More common- in patients who worked outdoors.
– In welders than other factory workers.
• Also associated with basal cell carcinoma,
porphyria cutanea tarda, polymorphous light
eruptions, xeroderma pigmentosa.

8. • ANGIOGENESIS FACTOR-(Wong) Prolonged UV
exposure causes biological changes in the
bowmans membrane
• UV Exposure: May induce hyperplasia in
limbal cells. These altered cells invade the
cornea and limbus which moves centripetally
with them

9. ALBEDO HYPOTHESIS
• Light entering the temporal limbus at 90degree is
concentrated at medial limbus (supported and
demonstrated by Coroneo)
• Related to corneal curvature.
• This explains the predominance of medial
pterygium.

10. Other theories
• Scarpa, Friede, and Kamel believed that chronic
inflammation in the form of conjunctivitis or
episcleritis initiates the process
• MICROTRAUMA: mechanical irritation by dust
particles, enhanced by tear flow from lateral to
medial.
• IMMUNOLOGY: Cell bound IgE irritant complexes
initiate the release of inflammatory mediators
from mast cells→ Release of stimulatory
factors→Development of pterygium.

11. • 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).

12. Genetic predisposition
• Expression of vimentin.
• P53 mutation leads to decreased apoptosis
and increased TGF-b which leads to increased
growth.

13. Pterygium- Degenerative or
proliferative ???
• long been considered a chronic degenerative
condition
• Classically described as“elastotic degeneration”
• Cˇilanova-Atanasova ascertained that the
degenerative or dystrophic changes in pterygium
were simply more pronounced than normal aging
conjuctiva
• In addition, pterygium tissue had proliferative
components that included epithelial hyperplasia
and the appearance of newly formed connective
tissue, blood vessels and fibrous elements

14. • Cameron- showed the evidence of transformed,
invading subconjuctival fibroblasts that grows
centripetally
• Austin and co-workers suggested- excessive
production of elastin material by actinically
damaged, proliferative subconjunctival fibroblasts
• Primary Pterygium is definitely locally invasive
• Also pterygium epithelium exhibits varying
degrees of abnormality, ranging from mild
dysplasia to carcinoma in situ

15. Limbal Stem Cell Deficiency and
Epithelial Abnormalities
• Kwok- propose that the initial biologic event in
pterygium was an alteration of limbal stem cells
due to chronic UV light exposure, resulting in
concomitant breakdown of the limbal barrier and
subsequent conjunctivalization of the cornea
• primary and recurrent pterygia exhibit
overexpression of the p53 tumor-suppressor
gene
• Presence of abberant apoptosis

16. Pterygium-Histopathology
• Three basic elements characterize the histologic
appearance
1. Epithelial covering of atrophic conjuctiva extends
beyond
2. Degenerated connective tissue- a bulky mass of
thickened, hypertrophied, and degenerated
connective tissue
– collagen component of which assumes a coiled, fibrillated
pattern reminiscent of elastic tissue
– The abnormal collagen shows basophilia and an affinity for
elastic tissue stains, but is not digested by elastase
– hence categorized as elastotic degeneration

17. Histology
Normal conjunctiva Pterygium

18. Histology

19. 3. Vascular element- New blood vessels, usually
congested, are dispersed among the
hypertrophied collagen fibers
• The episcleral bed beneath the pterygium is
hyperemic
• Tenon’s capsule is incorporated into the body
of the pterygium and contributes to its
vasculature and bulk

20. Histopathology cont..
• Immediately in front of the head of the
pterygium, an advancing row of fibroblasts
penetrates the cornea between Bowman’s
layer and the basement membrane of the
epithelium (grey zone or cap)
• Eventually tissue enters the cornea, Bowman's
layer is pushed posteriorly and eventually
becomes fragmented

21. Formed pterygium- schematic

22. Pterygium- Clinical feature
• A pterygium appears as a fleshy triangular band
of fibrovascular tissue
• axis of the triangle gently slopes superiorly on the
corneal side
• It has several components
– The cap
– The head
– The body
– The base
– Superior edge
– Inferior edge

23. • The cap
– The cap is a flat, grayish white avascular zone of
variable size located in the subepithelial corneal
tissue
– Sometimes a round, gray, coin-like extensions of
the cap precede it (“islets of Fuchs")
– some cases, a golden-yellow iron line may be seen
(Stocker's line)
– Between the head and the cap there are small
capillaries

24. Islets of Fuch’s
Stocker's line

25. • The head
– It is slightly elevated and
white
– It is the one site of firm
adhesion to the globe
• The body
– fleshy sheet of pink, highly
vascularized tissue
– delineated from the normal
conjunctiva superiorly and
inferiorly by sharp folds
– frequently reveals punctate
staining over the epithelial
surface of the body

26. • Clinical Grading of
pterygium
• As proposed by Donald
T H Tan
• Grade T1(atrophic)-
pterygium in which
episcleral vessels
underlying the body of
the pterygium were
unobscured and clearly
distinguished

27. • Grade T3(fleshy)- thick
pterygium in which
episcleral vessels
underlying the body of
the pterygium are
totally obscured by
fibrovascular tissue
• Grade T2(intermediate)-
All other pterygia that
do not fall into these
two categories

28. • Surgical recurrence correlated well with
translucency
– fleshy pterygium having the highest capacity for
recurrence
– Atrophic has the lowest

29. Clinical staging of pterygium
CLINICAL STAGING PATHOLOGICAL
STAGING
Stage I Exposure
conjunctivitis
Size and number of
Conjunctival vessels
Mild – moderate congestion
S/S of dryness
No formed lesions
Altered tear film
Mild vascular
response
Stage II Pinguecula and
pterygium
Distinct raised lesion on bulbar
conjunctiva
With or w/o abnormal
vascularization and inflammation
Cell injury
Inflammatory
response

30. Stage III Limbal pterygium Head is on or across the
limbus with or w/o an iron
line at the conjunctival
corneal interface
Vascularization and fibrous
proliferation
Symptoms more
pronounced
Lesion organization
Mixed proliferation
and degeneration
Stage IV Corneal pterygium Lesion 2mm or more into
cornea
Invasion of granulation
tissue
Zone of dellen
Stocker’s line
Infiltration of corneal
nerves- pain
Lesion b/w
epithelium and
bowman
Mixed proliferative
and degeneration

31. Stage V Compound pterygium Induced astigmatism
Symptoms more
frequent and severe
Lesion extended
into stroma
Mixed proliferative
and degeneration
Proliferation- Small lymphocytes and plasma cells
Degeneration- Swirls of type I collagen

32. Other types
• Primary double pterygium.
• Recurrent pterygium.
• Pseudopterygium.
• Malignant
pterygium(rare):recurrent
pterygium with restriction of
ocular movements.

33. Symptoms
• Asymptomatic
• Foreign body sensation
• Discomfort
• Congestion(redness)
• Irritation and grittiness-interference with
precorneal tear film.
• Interference with vision-obscuring visual axis
-inducing astigmatism(WTR)
• Cosmesis
• Diplopia

34. Differential diagnosis
Condition Signs and symptoms Tests
Pseudopterygium Most often hx of previous
infective, chemical, thermal,
or traumatic injury to the
cornea.
May occur at multiple
locations and is not restricted
to the 3 and 9 o'clock
(interpalpebral) positions.
-Slit-lamp examination: reveals
lesion to be adhesion of a fold
of conjunctiva, which has
occurred as a response to a
previous peripheral corneal
ulcer/inflammation.
-Lesion typically only fixed 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 head.

35. Pinguecula Does not encroach on the
cornea.
Slit-lamp examination: 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 blepharitis.
Infiltrate on corneal surface
is separated by a clear zone
from the limbus. Occur at 2,
4, 8, and 10 o'clock
position. Does not have
typical pterygium shape.
Often superior and inferior.
Corneal swab/scraping:
microscopy and culture
positive for infecting organism,
but infecting organisms are
often not detected, as many
cases are due to an
inflammatory reaction to
staphylococcal proteins

36. Corneal micropannus Hx of trachoma or lack of
corneal oxygenation due to
excessive contact lens
wear.
Slit-lamp examination:
reveals encroachment of
fine blood vessels onto
corneal surface.
Conjunctival carcinoma in
situ/ bowens epithlioma.
Rare. Does not have typical
pterygium shape. Not
restricted to the 3 and 9
o'clock (interpalpebral)
positions and can occur at
any position on the cornea.
Slit-lamp examination:
gelatinous-appearing mass.
Biopsy: cytological features
of a squamous cell
carcinoma, but the basal
membrane of the
epithelium remains intact.

37. Squamous cell
carcinoma
Rare. Does not have typical
pterygium shape. Not restricted
to the 3 and 9 o'clock
(interpalpebral) positions and can
occur at any position on the
cornea. May arise from a
pterygium, carcinoma in situ, or
de novo.
Slit-lamp examination:
surface may appear
keratinised and friable.
Biopsy: well-differentiated
squamous cell carcinoma
with invasion of the basal
membrane.
Limbal dermoid Benign choriostomatous tissue.
MC site:inferior temporal
quadrant.
Histology contains
abberant tissue like
epidermal
appendages,connective
tissue,skin,fatmuscle teeth.

38. Treatment Options
Managing the Menace

39. Historical aspects
• Susruta,(before 1000 B.C.)
the Indian physician who
was the world’s first
surgeon-ophthalmologist
described his operative
procedure, in which he
combined surgical removal
with adjunctive chemical
therapy

40. • 1953, Rosenthal reviewed surgical treatments
and stated that pterygia have been “incised,
removed, split, transplanted, excised,
cauterized, grafted, inverted, galvanized,
heated, dissected, rotated, coagulated,
repositioned and irradiated.”

41. Treatment
• Medical Treatment
– Symptomatic patients- Tear substitutes
– Inflammation- Topical steroids
– Sunglasses- to reduce UV exposure and decrease
growth stimulus

42. Surgical management
Indications for Surgery
1. Extension to the visual axis and induced
astigmatism.
2. Recurrent irritation.
3. Cosmetic- patient should be explained there is
fairly high risk of recurrence, which may be
more unsightly.

43. A variety of pterygium operations illustrated in
1950 (Archs Ophthal, 1950,Vol. 44)

44. • Modern pterygium surgery divided into four
main category
1. Bare sclera excision
2. Excision with conjunctival closure/transposition
3. Excision with antimitotic adjunctive therapies
4. Ocular surface transplantation techniques

45. 1.Bare sclera excission
• first described in 1948 by D’Ombrain
• Principle- leaving a strip of bare sclera allowed the
cornea, time to heal
• Recurrence rate range from 24% to 89%
• Recurrence is highly aggressive
• Symblepharon, restriction of motility and gaze
dependent diplopia may occur
• Complication
– Scleral thinning
– Irregular astigmatism
– Dellen formation at sceral bed

46. 2.Excision with Conjunctival
Closure/Transposition
• Bare sclera- does not comply with general
principles of wound healing and closure
• Wound closure may be simple approximation
of undermined conjunctival margins, with or
without relaxing incisions
• may be effected by conjunctival transposition
by a rotational pedicle flap from above or
below
• Recurrence rates are similar

47. 3.Excision with Adjunctive Medical
Therapy
• Sushruta- introduced chemicals or chemical cautery
• Radiation therapy- Terson in 1911(radium)
• Estrada used X-rays
• Iliff (1947)- employed beta irradiation with the means
of a radon applicator
• Beta irradiation
– Strontium 90 source
– total doses varying from 2000 rads to 6000 rads
– Treatment periods - single immediate postoperative dose
to weekly doses for six weeks after surgery
– Recurrence rate is around 10%

48. Beta Irradiation
• Complications
– Milder reactions
– sectoral cataract formation
– iris atrophy, scleral necrosis
– Melting
– Limbal stem cell deficiency
• Use should be restricted to severe or repeated
pterygium recurrences with a justifiable risk-benefit
ratio

49. Mitomycin C
• Kunimoto and Mori (1963) reported success with post-operative
MMC 0.04%
• inhibits DNA, RNA and protein synthesis
• 0.01% twice a day for five days
• Complications - Iritis, limbal avascularity, scleral melting
or calcific plaque formation, corneal decompensation,
scleral or corneal perforations, secondary glaucoma and
cataract
• surgeons now advocate a single intra-operative
application of MMC 0.02%
• Recurrence rate 2.3%

50. Thiotepa
• Nitrogen mustard alkylating agent
antimitotic property
• Radiomimetic- obliterates vascular endothelial
cells.
• Dose:1:2000 every 3 hours for 6 weeks.
• Used in bare sclera method.
• Complication: scleral thinning.
• Recurrence:10-16%

51. 5-fluorouracil
• Antiproliferative
• Inhibits thymidylate synthetase, thus inhibits
DNA.
• Only cells in the synthesis phase are affected,
allowing the remaining cells to continue to
proliferate after exposure to 5-FU.

52. Cyclosporine A
• Immunosuppresant drug.
• Dose: 0.05% topical for 3 months following
pterygium excision.
• Safe and effective.
• Low recurrence rate(3.4%)

53. Bevacizumab
• Inhibit neovascularisation.
• Stop the progression or prevent the
recurrence.
• Case reported by Wu and co workers.
Topical bevacizumab eye drops 25mg/ml 4times
for 3weeks.
• No recurrence in 1year follow up period.

54. 4. Ocular Surface Transplantation
Techniques
• transplantation procedures currently
performed are:
1. Conjunctival autograft transplantation
2. Modifications of conjunctival autografting:
a. Conjunctival rotational autografting
b. Annular conjunctival autografting
3. Conjunctival limbal autograft
4. Amniotic membrane transplantation

55. Conjunctival Autografting(CAU)
• Now recognized as procedure of choice for pterygium
surgery in terms of the efficacy and safety
• Recurrence rate is 2%
• 1977, Thoft first described the procedure of
conjunctival transplantation
• 1931 Gomez-Marquez, utilized superior bulbar
conjunctiva from the contralateral eye
• 1985 Keynon proposed the current conjunctival
autograft transplantation technique
• low recurrence rate (2%)

56. Fibrin glue and conjunctival auto graft
• 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.
graft dehiscence.
infection, discomfort, cost
Recurrence rate: less as compared to suture.

57. CAU-Post operative care
• Avoid exposure to sunlight.
• Use of dark sun glasses.
• Topical steroid antibiotic drops, topical
NSAIDS, artificial tears.

58. • Complete healing expected between 6-
8weeks.
• Topical medications should be tapered.
Lubricants should remain for 3months.
• Instruction to patient: avoid exposure to
sunlight.

59. Complications
• Graft failure.
• Granuloma formation.
• Conjunctival infection.
• Suture detachment.
• Delayed healing.
• Recurrence.

60. Conjuctival limbal autograft (CLAU)
• Principle- “corneal limbus as the source of
limbal stem cells responsible for corneal
epithelial cell maintenance”
• similar to conjunctival autografting
• Except that the limbal edge of the donor graft
is extended to include limbal epithelium
– superficial keratectomy
– or by superficial lamellar dissection
• Recurrence rate is similar or higher as to CAU

61. Amniotic Membrane Transplantation
• As an alternative basement membrane substrate
for use in ocular surface transplantation
• effective in reducing scarring and fibrosis
• recently has also been shown to suppress TGF-β
signaling of fibroblasts
• Advantages
– Relatively easy
– Good cosmetic result
• Disadvantage
– less efficient than conjunctival autografting
(Prabhasawat reported a 13% recurrence rate)

62. Pterygium Recurrence
• 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.

63. 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.

64. Excision of Recurrent Pterygia
• Why different??
– subconjunctival fibrous tissue is more abundant and is
tightly bound to the underlying sclera
– usually cannot be avulsed from the cornea and, therefore
must be dissected
– Important to resect all fibrous tissue and any symblephara
• Treatment option
– Superficial keratectomy
– Deep lamellar keratectomy and inlay graft
– Adjunctive therapy

65. Under trial
• ANECORTANE ACETATE:
Angiostatic steroid: Inhibits the blood vessels
Topical 1% have inhibitory effect on pterygium
regrowth following recurrenr pterygium
excision.

66. THANK YOU