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Ophthalmology > CONJUNCTIVA
Pterygium
Article Last Updated: Mar 27, 2008
AUTHOR AND EDITOR INFORMATION
Section 1 of 10  
Author: Jerome P Fisher, MD, FACS, Volunteer Assistant Professor, Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami School of Medicine
Jerome P Fisher is a member of the following medical societies: American Academy of Ophthalmology, American College of Surgeons, American Medical Association, and Florida Medical Association
Coauthor(s):
William Trattler, MD, Miami Center for Excellence in Eye Care; Consulting Staff, Department of Ophthalmology, Miami Baptist Hospital
Editors: Fernando H Murillo-Lopez, MD, Senior Surgeon, Unidad Privada de Oftalmologia CEMES; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Christopher J Rapuano, MD, Professor, Department of Ophthalmology, Jefferson Medical College; Co-Chairman of the Cornea Service, Co-Chairman of Refractive Surgery Department, Wills Eye Hospital; Lance L Brown, OD, MD, Ophthalmologist, Affiliated With Freeman Hospital and St John's Hospital, Regional Eye Center, Joplin, Missouri; Hampton Roy Sr, MD, Associate Clinical Professor, Department of Ophthalmology, University of Arkansas for Medical Sciences
Author and Editor Disclosure
Synonyms and related keywords:
pterygia, ocular mass, ocular lesion, corneal surface, corneal topography, diplopia, double vision, vision loss
Background
A pterygium is an elevated, superficial, external ocular mass that usually forms over the perilimbal conjunctiva and extends onto the corneal surface. Pterygia can vary from small, atrophic quiescent lesions to large, aggressive, rapidly growing fibrovascular lesions that can distort the corneal topography, and, in advanced cases, they can obscure the optical center of the cornea.
Pathophysiology
The pathophysiology of pterygia is characterized by elastotic degeneration of collagen and fibrovascular proliferation, with an overlying covering of epithelium. Histopathology of the abnormal collagen in the area of elastotic degeneration shows basophilia with hematoxylin and eosin stain. This tissue also stains with elastic tissue stains, but it is not true elastic tissue, in that it is not digested by elastase.
Frequency
United States
Occurrence within the United States varies with geographical location. Within the continental United States, prevalence rates vary from less than 2% above the 40th parallel to 5-15% in latitudes between 28-36°. A relationship is thought to exist between increased prevalence and elevated levels of ultraviolet light exposure in the lower latitudes.
International
Internationally, the relationship between decreased incidence in the upper latitudes and relatively increased incidence in lower latitudes persists.
Mortality/Morbidity
Pterygia can cause a significant alteration in visual function in advanced cases. They also can become inflamed, resulting in redness and ocular irritation.
Sex
Pterygia are reported to occur in males twice as frequently as in females.
Age
It is uncommon for patients to present with pterygia prior to age 20 years. Patients older than 40 years have the highest prevalence of pterygia, while patients aged 20-40 years are reported to have the highest incidence of pterygia.
History
Patients with pterygia present with a variety of complaints, ranging from no symptoms to significant redness, swelling, itching, irritation, and blurring of vision associated with elevated lesions of the conjunctiva and contiguous cornea in one or both eyes.
Physical
A pterygium can present as any of a range of fibrovascular changes on the surface of the conjunctiva and the cornea. It is more common for the pterygium to present on the nasal conjunctiva and to extend onto the nasal cornea, although it can present temporally, as well as in other locations.
- The clinical presentation can be divided into 2 general categories, as follows:
- One group of patients with pterygium can present with minimal proliferation and a relatively atrophic appearance. The pterygia in this group tend to be flatter and slow growing and have a relatively lower incidence of recurrence following excision.
- The second group presents with a history of rapid growth and a significant elevated fibrovascular component. The pterygia in this group have a more aggressive clinical course and a higher rate of recurrence following excision.
Causes
- Risk factors for pterygium include the following:
- Increased exposure to ultraviolet light, including living in subtropical and tropical climates
- Engaging in occupations that require outdoor activities
- A genetic predisposition to the development of pterygia appears to exist in certain families.
- A predilection exists for males to develop this condition in significantly higher numbers than females, although this finding may represent an increased exposure to ultraviolet light in this portion of the population.
Squamous Cell Carcinoma, Conjunctival
Other Problems to be Considered
Pseudopterygia (eg, chemical or thermal burn, trauma, marginal corneal disease)
Neoplasia (eg, carcinoma in situ, squamous cell carcinoma, other neoplastic diseases)
Pingueculae (ie, actinic lesions confined to the perilimbal conjunctiva that do not extend onto the cornea)
Imaging Studies
- Corneal topography can be very useful in determining the degree of irregular astigmatism induced by advanced pterygia.
- External photography can assist the ophthalmologist in following the progression of the pterygium.
Procedures
- Multiple different procedures have been advocated in the treatment of pterygia. These procedures range from simple excision to sliding flaps of conjunctiva with and without adjunctive external beta radiation therapy and/or use of topical chemotherapeutic agents, such as mitomycin C.
- Using free grafts of conjunctiva (with or without limbal tissue) at the same time as primary excision of the lesion has been widely advocated as the preferred treatment modality for aggressive pterygia. For moderate-to-severe pterygia, some corneal surgeons use amniotic membrane transplants. Both the conjunctival autografts and the amniotic membrane transplants may be sutured onto adjacent conjunctiva and subjacent cornea. Some corneal surgeons seal the graft tissue onto the underlying sclera with the aid of fibrin tissue glue rather than with sutures.
Medical Care
Patients with pterygia can be observed unless the lesions exhibit growth toward the center of the cornea or the patient exhibits symptoms of significant redness, discomfort, or alterations in visual function. Pterygia can be removed for cosmetic reasons, as well as for functional abnormalities of vision or discomfort.
Surgical Care
Surgery for excision of pterygia is usually performed in an outpatient setting under local or topical anesthesia with sedation, if necessary.
Postoperatively, the eye is generally patched overnight, and it is treated subsequently with topical antibiotics and anti-inflammatory drops and/or ointments.
Medical therapy of pterygia consists of over-the-counter (OTC) artificial tears/topical lubricating drops (eg, Refresh Tears, GenTeal drops) and/or bland, nonpreserved ointments (eg, Refresh P.M., Hypo Tears), as well as occasional short-term use of topical corticosteroid anti-inflammatory drops (eg, Pred Forte 1%) when symptoms are more intense. In addition, the use of ultraviolet-blocking sunglasses is advisable to reduce the exposure to further ultraviolet radiation.
Drug Category: Artificial tears (topical lubricating drops)
To lubricate the ocular surface and to fill in defects in the tear film.
| Drug Name | Artificial tears/topical lubricating drops (Refresh Tears, GenTeal [OTC]) |
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| Description | Artificial tears provide topical ocular surface lubrication in patients with irregular corneal surfaces and irregular tear films. These conditions are very common in the setting of pterygium. |
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| Adult Dose | 1 gtt in affected eye(s) qid and prn for irritation |
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| Pediatric Dose | Administer as in adults |
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| Contraindications | Documented hypersensitivity |
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| Interactions | None reported |
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| Pregnancy | A - Fetal risk not revealed in controlled studies in humans
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| Precautions | If symptoms persist despite continued use, reevaluate patient |
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Drug Category: Topical lubricating ointments
A more viscous lubricant of the ocular surface.
| Drug Name | Topical lubricating ointments (Hypo Tears, Refresh P.M. [OTC]) |
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| Description | A relatively more viscous lubricant for the ocular surface. These thicker preparations tend to blur the vision temporarily; therefore, they are generally used at night, except in patients with severe discomfort. |
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| Adult Dose | Apply to inferior cul-de-sac in affected eye(s) hs |
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| Pediatric Dose | Administer as in adults |
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| Contraindications | Documented hypersensitivity |
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| Interactions | None reported |
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| Pregnancy | A - Fetal risk not revealed in controlled studies in humans
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| Precautions | Patients using ocular ointments will have temporary blurring of vision and should avoid activities that require clear vision until the blurring subsides |
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Drug Category: Anti-inflammatory drops
To reduce inflammation on the ocular surface and other ocular tissues. Corticosteroids can be helpful in the management of inflamed pterygia by reducing the swelling of the inflamed tissues of the ocular surface adjacent to the lesions.
| Drug Name | Prednisolone acetate (Pred Forte 1%) |
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| Description | A topical corticosteroid suspension used to reduce inflammation in the eye. Use should be limited to eyes with significant inflammation not relieved by topical lubricants. |
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| Adult Dose | 1 gtt qid in affected eye(s) for a limited time, usually only 1-2 wk of continuous therapy |
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| Pediatric Dose | Not applicable, as pterygia are very rare in pediatric age group |
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| Contraindications | Documented hypersensitivity; patients with a history of herpes simplex dendritic keratitis or steroid responsive glaucoma |
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| Interactions | None reported |
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| Pregnancy | B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
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| Precautions | Can be absorbed systemically but systemic adverse effects are generally not seen in patients using topical prednisolone acetate drops; can be excreted in the milk of women who are breastfeeding |
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Further Outpatient Care
- Postoperatively, after pterygium excision, the topical steroids are slowly tapered. Patients on topical steroids need to be observed to avoid problems, such as elevated intraocular pressure and cataracts.
In/Out Patient Meds
Deterrence/Prevention
- Theoretically, minimizing exposure to ultraviolet radiation should reduce the risk of development of pterygia in susceptible individuals. Patients are advised to use a hat or a cap with a brim, in addition to ultraviolet-blocking coatings on the lenses of glasses/sunglasses to be used in areas of sun exposure. This precaution is even more important for those patients living in tropical or subtropical areas or for those patients who are engaged in outdoor activities with a high risk of ultraviolet exposure (eg, fishing, skiing, gardening, outdoor construction work).
Complications
- Complications of pterygia include the following:
- Distortion and/or reduction of central vision
- Redness
- Irritation
- Chronic scarring of the conjunctiva and the cornea
- Extensive involvement of the extraocular muscles may restrict ocular motility and contribute to diplopia.
- In patients who have not yet undergone surgical excision, scarring of the medial rectus muscle is the most common cause of diplopia.
- In patients with pterygia who have previously undergone surgical excision, scarring or disinsertion of the medial rectus muscle is the most common cause of diplopia.
- In patients with significantly elevated pterygia, focal drying and subsequent thinning of the adjacent cornea may rarely occur.
- Postoperative complications of pterygium repair can include the following:
- Infection
- Reaction to suture material
- Diplopia
- Conjunctival graft dehiscence
- Corneal scarring
- Rare complications may include perforation of the globe, vitreous hemorrhage, or retinal detachment.
- Late postoperative complications of beta radiation of pterygia can include the following:
- Scleral and/or corneal thinning or ectasia can present years or even decades after treatment.
- Some of these cases can be quite difficult to manage.
- In some cases, adjunctive use of topical mitomycin-C at and after pterygium surgery has been reported to cause similar ectasia or melting of the sclera and/or the cornea.
- The most common complication of pterygium surgery is postoperative recurrence. Simple surgical excision has a high recurrence rate of approximately 50-80%. The rate of recurrence has been reduced to approximately 5-15% with use of conjunctival/limbal autografts or amniotic membrane transplants at the time of excision.
- On rare occasion, malignant degeneration of epithelial tissue overlying an existing pterygium can occur.
Prognosis
- The visual and cosmetic prognosis following excision of pterygia is good. The procedures are well tolerated by patients, and, aside from some discomfort in the first few postoperative days, most patients are able to resume full activity within 48 hours of their surgery. Those patients who develop recurrent pterygia can be retreated with repeat surgical excision and grafting, with conjunctival/limbal autografts or amniotic membrane transplants in selected patients.
Patient Education
- Patients who are at high risk of the development of pterygia because of a positive family history of pterygia or because of extended exposure to ultraviolet irradiation need to be educated in the use of ultraviolet-blocking glasses and other means of reducing ocular exposure to ultraviolet light.
Medical/Legal Pitfalls
- As in any surgical procedure, careful informed consent must be obtained from the patient prior to surgery. While this procedure is fairly common with a very good visual prognosis in most patients, any ocular procedure can be associated with infection, perforation of the globe, vitreous hemorrhage, endophthalmitis, retinal detachment, or diplopia.
- Patients should be informed that redness and irritation may persist for longer than a month postoperatively.
- Patients should be informed about the chance of recurrence.
- The surgeon should check all biopsy results after excision of pterygium to rule out the possibility of an atypical presentation of a malignancy masquerading as a benign pterygium.
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Pterygium excerpt Article Last Updated: Mar 27, 2008
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