Table of Contents  
Year : 2015  |  Volume : 8  |  Issue : 3  |  Page : 312-314  

Pterygium: An enigma

Department of Ophthalmology, Padmashree Dr. D. Y. Patil Medical College Hospital and Research Centre (Dr. D. Y. Patil Vidyapeeth), Pimpri, Pune, Maharashtra, India

Date of Web Publication15-May-2015

Correspondence Address:
Renu M Magdum
7, Panchsheel Park, Aundh Baner Border, Pune - 411 007, Maharashtra
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How to cite this article:
Magdum RM. Pterygium: An enigma. Med J DY Patil Univ 2015;8:312-4

How to cite this URL:
Magdum RM. Pterygium: An enigma. Med J DY Patil Univ [serial online] 2015 [cited 2023 Sep 30];8:312-4. Available from:

Pterygium (Gk-pterygion) meaning "wing" is a nonmalignant, slow growing, wing shaped proliferation of fibrovascular tissue, arising from subconjunctival tissue, that may extend over the cornea.

There is greater incidence in people exposed to outdoor environment, especially in dry, dusty and sunny climate. There is a relation to high surface reflectance of ultraviolet (UV) light. Elliot provided evidence that drying of tear film by wind devitalizes tissues of medial third of palpebral aperture, thereby allowing active radiation to damage conjunctival and corneal epithelium and Bowman membrane. [1] Also, UV light from temporal side results in transcameral focusing and concentration at nasal limbus, thereby causing oxidative stress. This also explains why pterygium is uncommon in divergent and nonfixing eyes. Some studies have also implicated human papilloma virus (HPV) as a predisposing factor for pterygium. [2] However, HPV seems to be likely to increase susceptibility for pterygium formation rather than cause actual pterygium. Genes have also been implicated in some studies, such as apoptosis and cell cycle regulators, growth factors and their receptors such as vascular endothelial growth factor, and extracellular matrix modulators such as matrix metalloproteinases. [3]

Tseng et al. [4] have suggested that pterygium may represent an area of localized limbal stem cell deficiency.

Histopathologically, there is elastotic degeneration of collagen with fibrovascular proliferation with an overlying covering of epithelium. There is destruction of Bowman's layer in cornea leading to residual corneal scarring.

Pterygium may be staged according to length of encroachment on cornea. This is one of the most important indicators of severity of pterygium. It may cause induced astigmatism and cosmetic problems. Aggressive and recurrent pterygia may also cause lid deformities and restrictive strabismus.

Pterygia warrant treatment when they encroach upon the visual axis, induce significant regular or irregular astigmatism, or become cosmetically bothersome. Indications of activity are corneal epithelial irregularity, opacification of Bowman's layer and prominence of active blood vessels and inflammation.

Differential Diagnosis includes pseudopterygium, pinguecula, limbal dermoid, phlycetnular conjunctivitis, lymphoma of conjunctiva, squamous cell carcinoma of limbus, nodular episcleritis, Bowen's disease and conjunctival papilloma. Rate of (ocular surface squamous neoplasia) is reported to be as high as 9.8%, [5] hence all specimens must be submitted for histopathology examination.

Early pterygia may be treated with artificial tears and topical steroids. Use of sunglasses may reduce the exposure to UV radiations.

The various surgical treatment modalities that have been tried include bare sclera with intraoperative mitomycin C (MMC), bare sclera with beta radiation, sliding and rotational grafts, conjunctival autograft, amniotic membrane transplant, use of anti-metabolites like thiotepa, 5-fluorouracil and MMC and lamellar keratoplasty. Reported recurrence rate varies from 2% to 40%. No method is totally free from recurrence.

If pterygium is simply excised leaving the sclera bare or covered by sutured conjunctiva, the chances of recurrence are from 30% to 70%. Hence, the defect needs to be covered with conjunctival autograft or amniotic membrane. [6] Using a graft which is stuck using fibrin glue or sutured in place can reduce recurrence as low as 10%. [7] Adherence of the conjunctiva to underlying sclera inhibits fibroblasts migration into the surgical area, thus decreasing the risk of recurrence.

Conjunctival flaps are the most successful and most used procedures for pterygium surgery worldwide. [8] Free conjunctival graft is taken from superior bulbar conjunctiva (as it is covered with upper lid, it has less exposure to UV rays) However, the flaps should be made judiciously in patients likely to need glaucoma filtering surgery in future.

Suturing the graft can cause post op irritation and inflammation. Use of fibrin surgical glue to adhere the graft shortens surgical time and causes less pain and irritation postoperatively with a lesser rate of recurrence compared to sutures but has limitations such as high cost and limited availability. [9],[10] Also, being a blood derived product, it carries the potential risk for transmission of viral and prion diseases.

Amniotic membrane grafts may be needed for large primary and recurrent pterygia. This is a single layer of cuboidal epithelial cells from placenta with thick basement membrane and avascular stroma. It has anti-scarring, anti-angiogenic and anti-inflammatory properties and provides a new basement membrane for new epithelial cells to migrate and grow.

Lamellar keratoplasty has been tried for thin and scarred corneas following pterygium excision.

Mitomycin C is most commonly used adjunct therapy anti-metabolite. It is used intraoperatively as a 0.02-0.04% solution in a wek cel sponge and applied to underside of conjunctival flap or amniotic graft to be rinsed after 3 min or as postoperative 0.02% drops used four times a day for 10 days. Both regimens have shown a lesser rate of recurrence but sight threatening complications such as sclera melt and perforation have been reported.

Recently, conjunctival autograft without fibrin glue or sutures have been attempted using the patients own blood as a bioadhesive. [11] The surgeon allows a thin film of blood clot to form over the bare area after excising the pterygium. Any active bleeding is stopped by direct tamponade. A thin, tenon free conjunctival autograft is fashioned and aligned over the bare area. The edges are held by forceps for three to 5 min to give adequate time for the graft to get fixated. Most studies report excellent cosmesis and low recurrence rates comparable to current methods. Reported complications include graft loss and edge recession. This has been found to be comparable to fibrin glue for small and medium sized grafts but risk of graft displacement exists for larger grafts. [12]

Recently introduced modalities include use of angiostatic steroid anecortave acetate topical drops and subconjunctival and topical bevacizumab [13] which are still under evaluation.

  References Top

Elliott R. The aetiology and pathology of pterygium. Trans Ophthalmol Soc Aust 1966;25:71-4.  Back to cited text no. 1
Chalkia AK, Spandidos DA, Detorakis ET. Viral involvement in the pathogenesis and clinical features of ophthalmic pterygium (Review). Int J Mol Med 2013;32:539-43.  Back to cited text no. 2
Booth F. Heredity in one hundred patients admitted for excision of pterygia. Aust N Z J Ophthalmol 1985;13:59-61.  Back to cited text no. 3
Tseng SCG, Chen JJY, Huang AJW, et al. Classification of conjunctival surgeries for corneal disease based on stem cell concept. Ophthalmol Clin North Am 1990;3:595-610.  Back to cited text no. 4
Hirst LW, Axelsen RA, Schwab I. Pterygium and associated ocular surface squamous neoplasia. Arch Ophthalmol 2009;127:31-2.  Back to cited text no. 5
Youngson RM. Recurrence of pterygium after excision. Br J Ophthalmol 1972;56:120-5.  Back to cited text no. 6
Prabhasawat P, Barton K, Burkett G, Tseng SC. Comparison of conjunctival autografts, amniotic membrane grafts, and primary closure for pterygium excision. Ophthalmology 1997;104:974-85.  Back to cited text no. 7
Anduze AL. Conjunctival flaps for pterygium surgery. Ann Ophthalmol (Skokie) 2006;38:219-23.  Back to cited text no. 8
Koranyi G, Seregard S, Kopp ED. The cut-and-paste method for primary pterygium surgery: Long-term follow-up. Acta Ophthalmol Scand 2005;83:298-301.  Back to cited text no. 9
Marticorena J, Rodríguez-Ares MT, Touriño R, Mera P, Valladares MJ, Martinez-de-la-Casa JM, et al. Pterygium surgery: Conjunctival autograft using a fibrin adhesive. Cornea 2006;25:34-6.  Back to cited text no. 10
de Wit D, Athanasiadis I, Sharma A, Moore J. Sutureless and glue-free conjunctival autograft in pterygium surgery: A case series. Eye (Lond) 2010;24:1474-7.  Back to cited text no. 11
Singh PK, Singh S, Vyas C, Singh M. Conjunctival autografting without fibrin glue or sutures for pterygium surgery. Cornea 2013;32:104-7.  Back to cited text no. 12
Saxena S, Vishwkarma K, Khattri M, Kishore P. Multiple subconjunctival bevacizumab for advanced primary pterygium. Ann Ophthalmol (Skokie) 2010;42 Spec No:28-30.  Back to cited text no. 13


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