A team of researchers from Spain published a literature review in the journal Contact Lens & Anterior Eye to evaluate the link between physical activity and dry eye disease (DED) symptoms.
About the study
The meta-analysis review included 16 studies from PubMed and Web of Science databasesย that investigated the effects of physical activity on DED.
Of the 16 papers:ย
- Eight of the 16 papers studied the changes in dry eye signs after a single, short-term bout of aerobic exercise.
- The other eight papers studied the changes in dry eye symptoms in relation to long-term, regular physical activity.
These papers evaluated dry eye-associated signs, such as changes in tear volume, osmolarity, and/or biochemical composition, as well as dry eye subjective symptoms in patients primarily between the ages of 20 and 70 (with one paper assessing pediatrics and an inclusion of a small number of patients over the age of 70 in the remaining papers).
What did they find?
The studies found that physical activity was associated with:
- Increased tear volume
- Decreased tear osmolarity
- Prolonged tear breakup time (TBUT)
However, the duration of these changes and whether they are maintained after repeated bouts of exercise is still unknown.
Oxygen Bioavailability and Tear Osmolarityย
The researchers found that the exercise group had significantly lower tear film osmolarity than the control group. This suggests that physical activity may help to protect the eyes from dry eye, a condition that is characterized by dry, irritated eyes.
The researchers believe that the decrease in tear film osmolarity may be due to the increased blood flow to the eyes that occurs during physical activity due to the simultaneous activity of both autonomic divisions of the nervous system on the lacrimal glands. This increased blood flow helps to deliver more oxygen to the eyes, which can help to reduce tear film osmolarity.
Physical Activity May Improve Dry Eye Symptoms
Researchers have observed that habitual physical activity may lead to a long-term adaptation of the autonomic nervous system, increasing the so-called โparasympathetic tone.โ This could improve both lacrimal gland secretion and the physiological function of the meibomian glands, which are two important factors in maintaining healthy tear film.
The parasympathetic nervous system is responsible for many bodily functions, including tear production. When this system is activated, it sends signals to the lacrimal gland to produce tears. The meibomian glands are located on the eyelids and produce an oily substance that helps to keep the tears from evaporating too quickly.
Summary
This literature review presents compelling evidence indicating that physical activity may serve as a regulating stimulus to preserve the optimal functionality of the tear film, potentially reducing the signs and symptoms of dry eye disease (DED).
Reference:ย
Navarro-Lopez, S., Moya-Ramรณn, M., Gallar, J., Carracedo, G., & Aracil-Marco, A. (2023). Effects of physical activity/exercise on tear film characteristics and dry eye associated symptoms: A literature review.ย Contact Lens and Anterior Eye, 101854.
