1987
A well-defined triangular growth from the nasal conjunctiva that extends horizontally onto the cornea.
A benign, triangular, horizontal growth of the conjunctiva, arising from the inner side, at the level of contact of the upper and lower eyelids, associated with exposure to sunlight, low humidity and dust.
Does not usually interfere with vision, although in very advanced cases, it can extend close to the pupil and interfere with the visual axis.
When it extends more than a few millimeters onto the cornea, irregular astigmatism can result.
Irritation and redness that are often associated with these growths.
Higher rates among persons of African ancestry as well as those who worked outdoors.
The incidence is lower among persons who work outdoors but wear sunglasses.
Suggested sunlight exposure,more specifically, UV light exposure, is associated with this disorder.
An elevated, superficial, external ocular mass that usually forms over the perilimbal conjunctiva and extends onto the corneal surface.
It may be more common in occupations such as farming and welding.
Inflamed pinguecula – a yellow-white deposit close to the junction between the cornea and sclera, on the conjunctiva.
It is most prevalent in tropical climates with much UV exposure.
Although harmless, it can occasionally become inflamed.
Can develop on the nasal and/or temporal limbus.
Can affect either or both eyes.
Can vary from small, atrophic quiescent lesions to large, aggressive lesions.
Can be rapidly growing fibrovascular lesions distorting the cornea, and in advanced cases can obscure the optical center of the cornea.
Characterized by elastotic degeneration of collagen and fibrovascular proliferation, with an overlying covering of epithelium.
The incidence varies with geographical location, with a prevalence of less than 2% above the 40th parallel to 5-15% in latitudes between 28-36°.
Increased prevalence correlate with elevated levels of ultraviolet light exposure in the lower latitudes.
Internationally, decreased incidence in the upper latitudes and relatively increased incidence in lower latitudes persists.
Can cause alterations in visual function in advanced cases.
It can become inflamed, with redness and ocular irritation.
Occurs in males twice as frequently as in females.
Uncommon for patients to present before age 20 years.
Patients older than 40 years have the highest prevalence.
Patients aged 20-40 years are reported to have the highest incidence of pterygium.
Visual and cosmetic prognosis following excision is good, and most patients are able to resume full activity within 48 hours of their surgery.
Recurrent pterygia can be retreated with repeat surgical excision and grafting, with conjunctival/limbal autografts or amniotic membrane transplants in selected patients.
Patients should reduce exposure to ultraviolet light, with sunglasses, wearing a cap with a wide brim, and seeking shade.
Patients may have various complaints, ranging from no symptoms to redness, swelling, itching, irritation, and blurring of vision associated with elevated lesions of the conjunctiva and contiguous cornea in one or both eyes.
It is more common for the pterygium to present on the nasal conjunctiva and to extend onto the nasal cornea.
It can present temporally, as well as in other locations.
There are 2 clinical presentations:
One group with minimal proliferation and a relatively atrophic appearance.
This group tends to be flatter and slow growing and have a relatively lower incidence of recurrence following excision.
The second group presents with rapid growth and a significant elevated fibrovascular component.
Pterygia in this group have a more aggressive clinical course and a higher rate of recurrence following excision.
Risk factors include:increased exposure to ultraviolet light, living in subtropical and tropical climates, and 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, which may represent an increased exposure to ultraviolet light in this portion of the population.
Complications 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 with pterygia who have previously undergone surgical excision, scarring or disinsertion of the medial rectus muscle is the most common cause of diplopia.
Postoperative complications of pterygium repair include:
Infection
Adverse reaction to suture material.
Diplopia.
Conjunctival graft dehiscence.
Corneal scarring.
Perforation of the globe, vitreous hemorrhage, or retinal detachment.
Late postoperative complications of beta radiation of pterygia can include scleral and/or corneal thinning or ectasia, which can present years or even decades after treatment.
The most common complication of pterygium surgery is 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.
Rarely, malignant degeneration of epithelial tissue overlying an existing pterygium can occur.
Pingueculae are actinic lesions confined to the perilimbal conjunctiva that do not extend onto the cornea should also be considered in the differential diagnoses.
Corneal topography is useful in determining the degree of irregular astigmatism induced by an advanced pterygium, while photography can assist in following the progression of the pterygium.
Treatment 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 (MMC).
Free grafts of conjunctiva at the time as primary excision of the lesion has been advocated as the pref2242ed treatment modality for aggressive pterygia.
For moderate-to-severe pterygia, some corneal surgeons use amniotic membrane transplants.
Kheirkhah et al found that conjunctival inflammation was much more common with amniotic membrane transplantation than with conjunctival autograft after pterygium surgery, but with the use of mitomycin C, both techniques brought about similar final outcomes.
Patients 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.
Can be removed for cosmetic reasons, as well as for functional abnormalities of vision or discomfort.
Excision of a pterygium 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.
Minimizing exposure to ultraviolet radiation should reduce the risk of development of pterygium in susceptible individuals.
Medical treatment consists of over-the-counter (OTC) artificial tears/topical lubricating drops and/or bland, nonpreserved ointment, as well as occasional short-term use of topical corticosteroid anti-inflammatory drops when symptoms are more intense.
The use of ultraviolet-blocking sunglasses is advisable to reduce the exposure to further ultraviolet radiation.
Topical steroids 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.
Studies have suggested that the use of prescription sunglasses and smoking are associated with lower risk.
White race, male sex, and increasing age are associated with elevated risk.
Topical ophthalmological lubricants can be used to treat redness and irritation, buthave no effect on pterygium progression or growth.
Surgical removal of a pterygium is indicated if it affects or threatens to affect the visual axis or if eye movements are restricted.
Associated astigmatism is an indication for surgical excision.
Recurrence rate following surgical excision is 30% to 50%.
Additional therapies that reduce recurrence after excision include: a sliding conjunctival flap over bare-sclera excision, rotational conjunctival autografting, intraoperative or postoperative application of mitomycin C, beta irradiation, and amniotic membrane transplant.
Conjunctival autografting and application of mitomycin C are currently the most commonly used methods.
Use of surgical treatment using limbal stem cells and conjunctival autograft transplant have demonstrated much higher success rates and lower incidences of recurrence.
The major modifiable risk factor appears to be to limit exposure of the eyes to UV light/sunlight.