Pterygium, how living in the Caribbean affects us

07 July 2022

Jacqueline Piña, MD. Specialist in Anterior Segment and Ocular Diabetes.

Pterygium comes from the Greek word pterygion which means "fin". Others relate it to its resemblance to the wing of an insect. The pterygium is a fold of the conjunctiva (layer of transparent tissue that covers the white part of the eye), fleshy and with triangular-shaped penetration that advances over the cornea, which usually forms from the nasal side (side of the eye close to the nose), and may reach the pupil area in both eyes.

Pterygium is considered to be related to chronic irritant factors such as sun exposure due to ultra violet (UV) rays and others such as staying for long periods of time outdoors, in sunny, dusty and/or sandy environments, and places where the wind blows.

Epidemiological studies have found a higher geographical prevalence in the peri-equatorial zone known as the "pterygium belt", located between latitudes 370 north and south of the earth's equator, where countries such as Mexico, Brazil, Egypt, Saudi Arabia, India, Australia and our country are located. Although the exact pathophysiology of pterygium is not known, it is believed that ultraviolet light type B (UV-B), present in solar radiation, is the most important causal factor. One theory of pterygium formation explains that UV light can cause mutations in the P-53 tumor suppressor gene, resulting in its abnormal expression in the pterygium epithelium. This suggests that pterygium is not just a degenerative lesion, but may be the result of abnormal cell proliferation.

Pterygium can be classified, according to the American Academy of Ophthalmology as:

• Primary
• Recurrent

According to its extension it can have different degrees:

• I
• II
• III
• IV

Signs and symptoms, chronologically, are: first, small and gray corneal opacities near the nasal limbus; second, the conjunctiva grows over the opacities and progressively invades the cornea in a triangular shape; finally, a deposit of iron pigment can be seen in the corneal epithelium at the advancing head of the pterygium.

Medical treatment is reserved for the "red eye" episodes and inflammatory crises suffered by these patients. Topical steroidal and non-steroidal anti-inflammatory drugs and artificial tears are used. Surgical treatment is currently the most commonly used and is reserved for patients with grade II, III or IV pterygium. When surgery is performed in the more advanced grades, it has the disadvantage of recurrence and complications derived from the different surgical techniques. For this reason it is very important to operate on pterygium in its most incipient grades with small size. Several surgical techniques have been described for the treatment of primary and recurrent pterygium.

In 2011, we carried out a research study in which we demonstrated that the surgical technique we use at the Espaillat Cabral Institute offers very good results in terms of patient recurrence, reducing it to less than 20%. Although the treatment of advanced cases is challenging, we have good results with the use of mitomycin in our patients. In some cases it is also necessary to use amniotic membrane or conjunctival transplant taken from the unaffected eye.