What are the causes of keratoconus?

From the Guidelines

Keratoconus is caused by a combination of genetic, environmental, and medical factors that contribute to the thinning and bulging of the cornea, with the most significant risk factors including genetic predisposition, eye rubbing, and certain medical conditions such as atopic diseases and connective tissue disorders. The causes of keratoconus can be broken down into the following points:

• Genetic predisposition, with about 10% of patients having a family history of the condition 1
• Environmental factors, particularly eye rubbing, which creates mechanical stress on the cornea and can trigger or worsen keratoconus in susceptible individuals 1
• Certain medical conditions, including:
  • Atopic diseases like asthma, eczema, and allergies 1
  • Connective tissue disorders such as Ehlers-Danlos syndrome, osteogenesis imperfecta, and Down syndrome 1
  • Other genetic disorders, including congenital hip dysplasia, nail patella syndrome, pseudoxanthoma elasticum, hyper-immunoglobulin E syndrome, oculodentodigital dysplasia, and ichthyosis 1
• Hormonal changes, particularly during puberty and pregnancy, which can accelerate the progression of keratoconus
• Oxidative stress and inflammation in the cornea, which contribute to the breakdown of corneal tissue 1
• Imbalances in enzymes that maintain corneal structure, which can lead to weakening of the cornea 1
• Ultraviolet light exposure, which may damage corneal tissues over time
• Other factors, such as obstructive sleep apnea and high body mass index, which have been associated with an increased risk of keratoconus 1

From the Research

Causes of Keratoconus

The causes of keratoconus can be divided into several factors, including:

• Genetic factors: Keratoconus has been found to have a significant genetic component, with many cases showing autosomal inheritance patterns 2
• Environmental factors: Several environmental factors have been implicated in the onset and progression of keratoconus, including:
  • Contact lens wear 3
  • Eye rubbing 3, 2, 4, 5, 6
  • Atopy (such as hay fever and allergy) 2, 4, 5, 6
  • UV-A exposure 3
  • Geographical influences 3, 5
  • Nutritional and hormonal imbalances 3
  • Socioeconomic determinants 3
• Other factors: Other factors that may contribute to the development of keratoconus include:
  • Eczema and asthma 4
  • Family history of keratoconus 4
  • Ocular inflammation 4