5 Common causes of dry eye syndrome
The incidence of dry eye syndrome (DES) among contact lens wearers is quite high and often leads to the abandonment of contacts in favour of glasses. However, the underlying causes and possible solutions to dry eye syndrome can vary from patient to patient and to fully understand this issue, you need to take into account a number of factors:
- Meibomian gland dysfunction
MGD is a disorder in which the meibomian gland is blocked or has some sort of abnormality preventing it from secreting enough lipids into the tear film. As a result, the tear film easily evaporates leaving the eye surface dry. It is thought that MGD is the leading cause of dry eye syndrome.
Winter and early spring are especially difficult for contact lens users. This is because the air is generally drier in cold months, both outdoors and inside, resulting in drying out of the surface of the eye and contact lenses. The situation doesn't get much better in summer, as air conditioners in cars and offices also remove moisture from the air, potentially causing symptoms to reappear.
- Binocular vision disorder
Binocular vision disorder occurs when your eyes cannot align properly. The sufferers tend to overcompensate this to avoid blurred vision and as a result put a strain on the eye muscles, which can give symptoms very similar to dry eye syndrome: eye fatigue, feeling of dryness, etc. Research shows that there's a significant correlation between binocular vision issues and dry eye symptoms and that almost 50% of contact lens wearers with dry eye symptoms potentially have a binocular vision disorder.
According to the latest research reports, diabetes can cause severe dry eye symptoms, often making it impossible for patients to wear contact lenses. This particularly concerns diabetes with complications, which significantly increases the risk of developing dry eye. Researchers have been trying to explain the association between diabetes mellitus and DES. One of the current theories states that neuropathy is responsible for the increased incidence of dry eye in diabetic patients. This is because the body needs the nervous system to function properly to maintain ocular surface health and produce enough tears and lipids to protect it from drying. In addition, diabetes leads to meibomian gland dysfunction, which is one of the most common causes of dry eye syndrome.
- Increased pain sensitivity
Research shows that contact lens wearers with increased pain sensitivity may report dry eye symptoms and discomfort without any clinical signs of DES. The clinical research into this issue was initiated because there is a discrepancy between the real signs and symptoms of discomfort and patient's subjective reports and because clinical tests for dry eye often fail to predict symptoms correctly.
During the study, the researchers compared the subjects’ Pain Sensitivity Questionnaire (PSQ) scores with their Ocular Surface Disease Index (OSDI) questionnaire results, The analyses performed by the researchers showed a significant, positive correlation between PSQ and OSDI scores. This means that pain sensitivity has a serious impact on perceived contact lens comfort and proves that the Pain Sensitivity Questionnaire is a useful tool in assessing it.