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Pterygium and its management

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Pterygium and its management

  2. 2.  Derived from Greek word ‘pterygion’ means 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.
  3. 3.  World wide distribution.  More common in warm and dry climates.  Prevalence : 22% equatorial areas. <2% in latitudes between 28-38degree.  Direct relation with amount of UV exposure.
  4. 4.  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.
  5. 5.  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.
  6. 6.  ANGIOGENESIS FACTOR:Prolonged UV exposure causes biological changes in the bowmans membrane.  Altered protein so formed could act as angiogenic/ pterygiogenic factor.
  7. 7.  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).
  8. 8.  Exposure to UVB+altered tear film  Injury and susceptibility  Loss of collagenase and dehydration  Accumulation of Extracellular matrix  Antigenic,type1 HS Pinguecula  Fibroblastic reaction Inflammation  PTERYGIUM PTERYGIUM
  9. 9.  Light entering the temporal limbus at 90degree is concentrated at medial limbus.  Related to corneal curvature.  This explains the predominance of medial pterygium.
  10. 10.  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 bowmans membrane.
  11. 11.  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.
  12. 12.  Expression of vimentin.  P53 mutation leads to decreased apoptosis and increased TGF-b which leads to increased growth.  RECURRENT PTERYGIUM- stem cells are more scattered and expression pattern is more denser.
  13. 13.  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).
  14. 14.  Elastotic degeneration of collagen.(Not a true elastic tissue)  Fibro vascular proliferation with an overlying covering of epithelium-characterized by Cellular proliferation. Tissue remodeling. Neovascularisation.  Subepithelial tissue shows basophilic degeneration.
  15. 15.  Destruction of bowman’s membrane in the cornea.  So there is residual corneal scarring when these growth are removed.  Epithelium shows secondary changes like orthokeratosis,acanthosis,dyskeratosis.  Mast cells occur in increased number.
  16. 16. Normal conjunctiva Pterygium
  17. 17. CLINICAL STAGING PATHOLOGICAL STAGING 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 vascularization and inflammation
  18. 18. 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 interface proliferation and Vascularization and degeneration fibrous proliferation Symptoms more pronounced Stage IV Corneal Lesion 2mm or more Lesion b/w pterygium into cornea epithelium and Invasion of granulation bowman tissue Zone of dellen Mixed Stocker’s line proliferative Infiltration of corneal and nerves- pain degeneration
  19. 19. Stage V Compound Induced astigmatism Lesion extended pterygium Symptoms more into stroma frequent and severe Mixed proliferative and degeneration Proliferation- Small lymphocytes and plasma cells Degeneration- Swirls of type I collagen
  20. 20.  Fuch’s patches.  Stocker’s line.  Hood.  Head.  Body.  Base.  Superior edge.  Inferior edge.
  21. 21.  Progressive: thick fleshy marked vascularity. It has opaque infitrative spot known as cap. Stocker’s line.  Atrophic/stationary: thin attenuated poor vascularity no cap.
  22. 22. Progressive pterygium Atrophic pterygium
  23. 23.  Primary double pterygium.  Recurrent pterygium.  Pseudopterygium.  Malignant pterygium(rare):recurrent pterygium with restriction of ocular movements.
  24. 24.  Asymptomatic  Foreign body sensation  Discomfort  Congestion(redness)  Irritation and grittiness-interference with precorneal tear film.  Interference with vision-obscuring visual axis -inducing astigmatism  Cosmesis.
  25. 25.  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.
  26. 26. 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 head.
  27. 27. 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.
  28. 28. 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 the epithelium remains intact.
  29. 29. 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 membrane. Limbal dermoid Benign choriostomatous Histology contains tissue. MC site:inferior abberant tissue like temporal quadrant. epidermal appendages,connectiv e tissue,skin,fatmuscle teeth.
  30. 30.  Symptomatic patients- Tear substitutes  Inflammation- Topical steroids  Sunglasses- to reduce UV exposure and decrease growth stimulus
  31. 31. 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.
  32. 32.  Free conjunctival autograft for primary and recurrent pterygium.  Pre op evaluation: 1. Evaluation of pterygium. 2. Evaluation of superior bulbar conjunctiva. 3. Pre op preparation. 4. Anaesthesia and sedation.
  33. 33. Preparation and drape. Place anaesthetic drops or topical vasoconstrictor. Ask patient to look opposite side of pterygium.
  34. 34.  Goal: Achieve a normal, topographically smooth ocular surface  Dissect a smooth plane toward the limbus  Preferable to dissect down to bare sclera at limbus  Bare sclera = remove loose Tenon’s layer and leave episcleral vessels intact
  35. 35.  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. Recurrence rate: less as compared to suture.
  36. 36.  Avoid exposure to sunlight.  Use of dark sun glasses.  Topical steroid antibiotic drops, topical NSAIDS, artificial tears.  POD3/5 graft acquires redness.
  37. 37.  Complete healing expected between 6- 8weeks.  Topical medications should be tapered. Lubricants should remain for 3months.  Instruction to patient: avoid exposure to sunlight.
  38. 38.  Graft failure.  Granuloma formation.  Conjunctival infection.  Suture detachment.  Delayed healing.  Recurrence.
  39. 39. Bare sclera technique: -recurrence: 5-68% (primary) 35-82% (recurrent)
  40. 40.  Subconjunctival scarring limitation of movements diplopia.  Disinsertion of medial rectus muscle.  Scleral perforation.  Corneal irregularity due to deep stromal excision.
  41. 41.  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.
  42. 42.  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.
  43. 43.  AIM: To reduce recurrence. 1. Corticosteroids- post operative use of topical steroids can reduce inflammatory reaction and revascularization at the operative site. 2. No significant role in prevention of recurrence.
  44. 44.  Antibiotic and antineoplastic properties.  Blocks the DNA synthesis.  Concentration: 0.02%  Use: intraoperative to the area of resection with sponge for 2min followed by irrigating with balanced salt solution.
  45. 45.  Side effects: pyogenic granuloma dellen of sclera. perforation of eye. glaucoma. cataract. corneal edema.  Recurrence: 3-25% (intraoperative) 5-54%(postoperative)
  46. 46.  Post operative period LCAG MMC 3 month 1 - 6 month 1 2 12 month - 1 18 month - - Total 02 (4%) 03 (6%)
  47. 47.  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%
  48. 48.  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.
  49. 49.  Immunosuppresant drug.  Dose: 0.05% topical for 3 months following pterygium excision.  Safe and effective.  Low recurrence rate(3.4%)
  50. 50.  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.
  51. 51.  Reduces mitosis in rapidly dividing vascular endothelial cells.  Dose : 15Gy units in single or divided doses.  Recurrence: 4.3%-35% with bare sclera or simple conjunctival closure.  Complications: scleral necrosis endophthalmitis cataract formation. conjunctival telangiectasia.
  52. 52.  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.
  53. 53.  Useful in:  very large conjunctival defects.  To preserve superior conjunctiva for future glaucoma surgery.  Advantages: faster healing rate less discomfort. lower recurrence rate(2% in 1year follow up)
  54. 54.  ANECORTANE ACETATE: Angiostatic steroid: Inhibits the blood vessel’s. Topical 1% have inhibitory effect on pterygium regrowth following recurrenr pterygium excision.
  55. 55.  Surgical and medical management of pterygium-Ashok garg.  Pterygium-a practical guide to management,L. Alfred andeze.  Kanski clinical ophthalmology.