Atopy is described as a hereditary propensity to form immunoglobulin E antibodies (IgE) as a reaction to minute amounts of certain environmental factors, including house dust mites, pollen, or even food allergens1. In addition, atopy is a hereditary propensity for developing allergic hypersensitivity. Studies show that the most prevalent representations of atopic dermatitis are allergic asthma and allergic rhinitis, followed by allergic dermatitis and food allergies1. Allergies are the clinical expression of atopic diseases; nevertheless, not all allergies are atopic diseases2. The most common characteristic of all atopic diseases is hypersensitivity of the skin and mucous membranes, and this hypersensitivity often runs in families3.
Several risk factors have been identified for atopic diseases. Risk and triggering factors such as allergens, tobacco smoke, and occupational factors are the causative agents of allergic reactions or acute asthma in atopic patients; although a distinction must be made between them, there are also connections to be found; for instance, cigarette smoke exposure as well as allergens can be long-term risk factors for allergies or even asthma development. People with atopic dermatitis have a greater propensity to respond to specific antigens in the environment4.
Epidemiological studies show that the incidence and prevalence of atopic diseases like asthma, hay fever, and atopic dermatitis are increasing in developing countries. However, the prevalence of atopic diseases has reached a plateau in developed western countries 1.
Atopic involvement in a person is linked with an increased incidence of development of one or more of the atopic conditions; asthma, atopic dermatitis (eczema), allergic rhinoconjunctivitis/hay fever, as well as food allergies. However, atopy may manifest as asymptomatic sensitization, i.e., it may be seen among patients who have proven allergic sensitization but may not display a clinical allergic reaction1.
Keratoconus is defined as an asymmetrical and worsening disease with severe effects on the acuity of vision as well as the life quality of the cases. It is also defined as a gradual thinning of the corneal stroma resulting in modification of the tissue structure. Irregular astigmatism occurs due to cone-shaped cornea. Corneal ectasia usually presents in young adults at puberty and may advance till the 3rd to 4th decade when physiological corneal cross-linking is established to be the disease's stabilizing agent5.
The exact causes of keratoconus are still poorly understood. While most forms of keratoconus are known to be sporadic, several researchers have revealed a significant number of hereditary family keratoconus, whether via an autosomal recessive or dominant form. LOX is recognized as the collagen cross-linking enzyme lysyl oxidase, a gene important for cross-linking collagen, while elastin is viewed as a probably reliable indicator in keratoconus formation leading to a damaged corneal architecture. Environmental causes, including eye rubbing and the use of rigid contact lenses, have been linked to the condition. Those with allergic conditions have an increased chance of keratoconus formation5. The most frequently noted risk factors of excessive eye rubbing in KC were allergies and atopic disorders. Nevertheless, irritation triggered by atopy, which contributes to rubbing of the eye, may be the most important contributing factor to KC6.
The thinning of the cornea results in unequal astigmatism and myopia, which leads to mild to severe vision problems. Keratoconus is bilateral among 90% of cases, but is typically asymmetrical in intensity as well as advancement. While no symptoms can accompany the initial stages of the disorder, as it advances, the common manifestation is mild to significant vision problems due to unequal astigmatism, myopia, and corneal scarring in some cases6.
Keratoconus disease is a bilateral, non-inflammatory corneal ectasia with an occurrence in the overall public of around one per 20007. The frequency of keratoconus disease in the city of Asir in Saudi Arabia is twenty patients for every 100,000 people8. In total, 1,638 people from one of the five cities in KSA were referred to King Khaled's Eye Specialist Hospital for the treatment of keratoconus at an average annual reference rate of 136.5 cases per year. The overall distribution of people with keratoconus was almost similar among males and females, with a greater incidence of younger patients aged between 16–269. Keratoconus is an unexplained etiological condition, although much research has exhibited a connection with atopy10. From the start of the twentieth century, several descriptive surveys have documented the relationship between keratoconus and atopy11. In addition, Keratoconus was identified in several different clinical studies. It may be an isolated sporadic disorder, or it may be combined with other uncommon hereditary diseases as well as with Down syndrome, connective tissue diseases, Leber's congenital amaurosis, hard contact lens wear, eye rubbing, and a strong family history of the condition12.
An association has been established between atopy and keratoconus for over 50 years, but several clinical studies have reported opposite findings. In studies carried out about 30 years ago, in 59 percent of keratoconus cases, an increased level of serum immunoglobulin E was observed. Nevertheless, as many of the people with allergic eye conditions rub their eyes vigorously, it has remained uncertain whether atopy itself or eye rubbing is the keratoconus-related cause. Harrison et al demonstrated that the condition occurs more often on the dominant hand side in atopic keratoconus cases. A case-control study published in 2000 by Bawazeer et al showed that there was an association between atopy and keratoconus, in addition to eye rubbing and keratoconus family history, in the univariate association;and demonstrated that only eye rubbing was still a strong indicator of keratoconus, in the multivariate study. They clarified that atopy may lead to keratoconus disease but most likely was a result of eye rubbing combined with atopy irritation13. Our study aims to estimate the prevalence of atopy and its associated factors among keratoconus patients in the Jazan region.