What is the pterygium?
In this article we will explain what the pterygium is. Pterygium comes from the Greek pterys which means little wing, fin. Pterygium is a vascularized lesion of the conjunctiva of the eye that can invade the cornea, cause astigmatism and decrease visual acuity.
It is located in the midline of the eye, in the space between the upper and lower eyelids. It has a triangular shape, it can be found on the temporal side but It is more common on the nasal side and may affect One or both eyes.
It is more frequent in tropical and subtropical climates and very rare in cold countries. It is directly related to ultraviolet radiation by exposing the eye to sunlight without filters or protection.
It occurs in farmers, workers and in those jobs that are done outdoors because they are more exposed to solar radiation and dust. As well seems to be related to contact with solvents and chemicals.
As well It has been related to the dryness of the environment and the presence of wind which accelerates tear evaporation. It has a hereditary component and is related to immunological diseases.
It occurs in individuals between 20 and 50 years being more frequent in the rural than in the urban environment, it has more prevalence in African Americans without gender differences. In Spain, its incidence is higher in areas with more sunshine, mainly Canary Islands, Andalusia and Levante.
Symptoms of Pterygium
Symptoms may vary depending on the activity, size and location of the pterygium.
In the active pterygium one observes thickened lesion, with inflammation, hyperemic and a whitish area at the apex of the triangle.
The symptoms produced by active pterygium include:
Read also: Macular degeneration
It is the pterygium observed in temperate countries. Its incidence is lower, slower growth and less obvious symptoms. One appears flat lesion, without inflammation, No vascularization and no signs of growth.
Symptoms are very scarce or non-existent.. The size of the pterygium is directly proportional to the symptomatology. At a larger size, it occupies more surface of the cornea and, therefore, affects vision more.
Depending on the location, they are more symptomatic those that affect the area of the visual field of the cornea. The symptoms of the pterygium will be less obvious when it is in the periphery of the eye.
You may also be interested: Effects of ultraviolet rays on vision
- Glasses with ultraviolet filters between 90 and 100% protection index. They must be used in the susceptible population and especially in children.
- Wide-brimmed hats
For those cases in which it does not produce great symptoms:
In symptomatic cases, the only solution is surgery. In general, the pterygium will continue to grow and if not removed, the symptoms will increase. It can be carried out in different ways:
- Simple exeresis: it is done by removing the pterygium and letting it heal on its own from the conjunctiva. It is an intervention not recommended because the pterygium appears again in 40 – 80% of cases. It is currently not recommended.
- Simple conjunctival closure: excision and suture of the conjunctival edges. It also reappears in 45-70% of cases, so it is only recommended in elderly people where recurrences with minors.
- Conjunctival and limbal autograft: it is the Surgical technique of choice due to its lower recurrence. It is the intervention with less recovery time and fewer relapses. It can be done with continuous suture or with biological fibrin tissue adhesives.
The preference in the use of synthetic adhesives over sutures is due to the fact that they are biocompatible, produce little or no inflammation, do not generate a foreign body reaction or incidental death and are biodegradable.
- Free conjunctival autograft: this technique It is done by excision of the head and body part of the pterygium and subsequent coverage with the exposed sclera with conjunctiva of the patient. It has good results, although lower than the prior art.
It is performed as a complement to the surgical treatment to minimize the risk of recurrence:
- Antimitotics: prevent cell replication and they have the mission to cancel or delay the growth of the pterygium tissue. Although they reduce the risk of recurrence of the pterygium, they have toxic effects and complications that, at times, discourage their use. The most used is Mitomycin C.
- Antiangiogenic: prevent vascular proliferation which provides nutrients to the pterygium tissue and facilitates its growth, subtracting transparency to the cornea and making vision difficult. Currently, topical bevacizumab is in experimental clinical use.
- Beta therapy: it consists of postoperative radiotherapy of the pterygium with beta radiation to reduce recurrences. It produces inhibition of cell mitosis preventing recurrence. It has effects similar to Mitomycin but with fewer side effects.
In conclusion, the pterygium is a vascularized lesion of the conjunctiva of the eye that can invade the cornea and It can cause astigmatisms and decreased visual acuity.