Pterygium and its management

1. PTERYGIUM AND ITS MANAGEMENT MODERATOR : DR SURESH.H.H PRESENTER :DR ANJALI

2. Anatomy of conjunctiva

3. Histology of normal conjunctiva

4. 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. DEFINITION- PTERYGIUM

5. 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. EPIDEMIOLOGY

6. 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.

7. 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. ETIOPATHOGENESIS.

8. ANGIOGENESIS FACTOR :Prolonged UV exposure causes biological changes in the bowmans membrane. Altered protein so formed could act as angiogenic/ pterygiogenic factor.

9. 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).

10. 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

11. Light entering the temporal limbus at 90degree is concentrated at medial limbus. Related to corneal curvature. This explains the predominance of medial pterygium. ALBEDO HYPOTHESIS

12. Dry and dusty environment . Drying of the tear film by wind devitalizes tissue of medial 3 rd of the palpebral aperture. This allows the actinic radiation to damage the conjunctival , corneal epithelium and bowmans membrane.

13. 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.

14. 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. Genetic predisposition

15. 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).

16. 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. PATHOLOGY

17. 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.

18. Histology Normal conjunctiva Pterygium

19. Histology

20. 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 Clinical staging of pterygium

21. 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

22. 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

23. Fuch’s patches. Stocker’s line. Hood. Head. Body. Base. Superior edge. Inferior edge. Parts of pterygium

24. Parts of pterygium

25. Progressive: thick fleshy marked vascularity. It has opaque infitrative spot known as cap. Stocker’s line. Atrophic/stationary : thin attenuated poor vascularity no cap. Clinical types of pterygium

26. Clinical types Progressive pterygium Atrophic pterygium

27. Stocker’s line

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

29. Double pterygium involving the visual axis

30. Asymptomatic Foreign body sensation Discomfort Congestion(redness ) Irritation and grittiness-interference with precorneal tear film. Interference with vision-obscuring visual axis -inducing astigmatism Cosmesis. Signs and symptoms

31. 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. Signs

32. 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. Differential diagnosis Condition Signs and symptoms Tests

33. 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

34. 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.

35. 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.

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

37. Extension to the visual axis and induced astigmatism. Recurrent irritation. Cosmetic- patient should be explained there is fairly high risk of recurrence, which may be more unsightly. Indications for surgery

38. Free conjunctival autograft for primary and recurrent pterygium . Pre op evaluation: Evaluation of pterygium. Evaluation of superior bulbar conjunctiva. Pre op preparation. Anaesthesia and sedation. Surgical technique

39. Preparation and drape. Place anaesthetic drops or topical vasoconstrictor. Ask patient to look opposite side of pterygium. Surgical technique

40. Pterygium Excision 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

41. 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. Fibrin sealant and conjunctival auto graft

42. Avoid exposure to sunlight. Use of dark sun glasses. Topical steroid antibiotic drops, topical NSAIDS, artificial tears. POD3/5 graft acquires redness. Post operative care

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

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

45. Bare sclera technique: -recurrence: 5-68% (primary) 35-82% (recurrent) Other surgical methods

46. Simple closure: recurrence 45-69%

47. Sliding flap: recurrence 45-69%

48. Rotational flap: recurrence 4-6%

49. Subconjunctival scarring limitation of movements diplopia. Disinsertion of medial rectus muscle. Scleral perforation. Corneal irregularity due to deep stromal excision. Complications

50. 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.

51. 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.

52. AIM: To reduce recurrence. Corticosteroids - post operative use of topical steroids can reduce inflammatory reaction and revascularization at the operative site. No significant role in prevention of recurrence. Adjunctive therapy

53. 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. Mitomycin C

54. Side effects: pyogenic granuloma dellen of sclera. perforation of eye. glaucoma. cataract. corneal edema. Recurrence: 3-25% (intraoperative) 5-54%(postoperative)

55. Post operative period LCAG MMC 3 month 1 - 6 month 1 2 12 month - 1 18 month - - Total 02 (4%) 03 (6%) Comparison of recurrence rate

56. 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% Thiotepa

57. 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. 5-fluorouracil

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

59. 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. Bevacizumab

60. 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. Beta radiation

61. 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. Amniotic membrane.

62. Amniotic membrane application after pterygium excision

63. 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)

64. ANECORTANE ACETATE: Angiostatic steroid: Inhibits the blood vessel’s. Topical 1% have inhibitory effect on pterygium regrowth following recurrenr pterygium excision. Under trial

65. Surgical and medical management of pterygium-Ashok garg . Pterygium-a practical guide to management,L . Alfred andeze . Kanski clinical ophthalmology. References

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