How are pterygiums formed

Many friends who have pterygium in their eyes don’t know how pterygium is formed. Most of them suddenly find that there is something in their eyes. In fact, pterygium has no effect on vision. If it affects vision, surgical removal can be considered. Now let us look at the causes of pterygium so that we can do daily prevention to prevent the occurrence of pterygium.

Causes

There is still much controversy about the causes of the disease. It is generally believed that it may be the result of the combined effects of internal factors (genetic factors) and external factors (environmental factors). Among external factors, ultraviolet rays in sunlight are the most important environmental factor. In addition, wind, sand, dust, dryness, etc. are also important environmental factors that affect the incidence of the disease.

1. Environmental factors: Epidemiological survey results show that the incidence rate is significantly increased among people living in hot, sunny and dusty areas, and outdoor workers are also susceptible to the disease. Some people have found through experiments on rats that high-dose ultraviolet radiation can cause epithelial hyperplasia, degeneration of the anterior elastic layer and blood vessel formation in the corneal stroma, indicating that the formation of pterygium is significantly related to the effects of ultraviolet rays and may be the most important environmental factor.

2. Genetic factors have a certain influence on the occurrence of pterygium, but it does not play a decisive role. This inheritance is a dominant trait with low penetrance. But it seems that the actual disease is not hereditary. What is inherited is the tendency of the eye to develop pterygium due to the influence of environmental stimuli.

3. Immune factors are considered to be related to immunology because plasma cells, lymphocytes and immunoglobulins are found in pterygium. Monoclonal antibody studies have shown that almost all lymphocytes are T cells, which cause cell-mediated immune responses and type IV hypersensitivity reactions. Immunofluorescence studies showed that the immunoglobulins were IgG and IgE, with IgG being predominantly within the corneal stroma, consistent with areas of plasma cell and lymphocytic infiltration. IgE is mainly distributed in the epithelium and matrix areas. The presence of IgE indicates a type I or immediate hypersensitivity reaction. Immunofluorescence studies of normal conjunctiva revealed no IgG or IgE. If IgE persists, it will lead to chronic inflammation. This antigenic stimulus can come from exogenous factors like pollen, dust particles or even viruses. It is worth noting that although IgE is sometimes discovered by chance, this immunological theory still has a certain appeal. The presence of T lymphocytes, IgG, and IgE in pterygium indicates that humoral and cell-mediated hypersensitivity reactions are closely related to the occurrence of pterygium.