What can tears tell us?
Vision is one of the most important senses and its disorders, especially glaucoma, significantly affect the quality of life. Various methods are used in medical practice to diagnose eye diseases. Currently, the examination of biomarkers (molecules indicating the state of the organism) in tears is another potential diagnostic and prognostic method. Dominika Mravec Bencúrová and Pavlína Daňková from the Laboratory of Molecular Anthropology at the Department of Anthropology and Human Genetics, Faculty of Science, Charles University, investigated the possibility of using cytokines in tears for these purposes.
Glaucoma is a group of eye diseases characterized by damage to the optic nerve, which transmits visual signals from the retina to the brain. It is a chronic disease that usually progresses slowly and can lead to loss of vision or even complete blindness if not treated in time. A major factor in the development of glaucoma is increased intraocular pressure, which can result from an imbalance between the production and drainage of ocular fluid. There are different types of glaucoma, the two main ones being primary open-angle glaucoma and primary angle-closure glaucoma. The study focused on the former variant. This form of glaucoma is called "open-angle" because the angle between the iris and cornea is normal and open, allowing normal outflow of ocular fluid. Even though the angle is open, there may be problems with the outflow of ocular fluid from the eye. The fluid drains into the trabecular meshwork, which is a kind of filter that allows the fluid to drain out of the eye. In open-angle glaucoma, the trabecular meshwork does not normally perform its function and the result is an accumulation of ocular fluid and an increase in intraocular pressure.
This type of glaucoma often affects people gradually and without symptoms in its early stages. Diagnosis of glaucoma involves regular eye examinations, measurement of intraocular pressure, optic nerve examination, and perimetry (peripheral vision test). Another option is diagnosis using biomarkers. Biomarkers are measurable and observable indicators of biological processes or body conditions that can be used to diagnose, monitor the course of disease, predict response to treatment or assess the risk of developing a particular disease. These markers can be detected in body fluids such as blood, urine, cerebrospinal fluid, and tears. Currently, a potential way to diagnose glaucoma is to examine biomarkers in tears. This possibility was investigated by a group of researchers in their study.
The aim of the study was to analyse the presence of cytokines in tears that serve as indicators of inflammation or cell death. Their level reveals the general condition of the ocular surface and allows monitoring of disease progression. Seventy-eight people participated in the study, 24 of them are glaucoma patients and 9 are ocular hypertension patients, the rest are healthy people, serving as a control group. Tears were collected with a special micropipette. Six different cytokines (IL1β, IL10, IL4, IFNγ, MIF and VEGF) were detected in the tears of the patients. Based on the results, the researchers concluded that the ocular surface of patients with treated open-angle glaucoma and untreated ocular hypertension exhibited an inflammatory environment. In addition, stronger inflammation was observed in patients with ocular hypertension.
Confirming that tears contain cytokines offers a potentially new and non-invasive way of examining the eye. This method could be particularly crucial at stages when clinical signs are not yet apparent. The importance of this study for the future lies in pushing the boundaries of glaucoma diagnosis, allowing potential risk groups to be identified and treatment to be initiated in the early stages of the disease. Biomarkers in tears could provide physicians and patients with a new tool to monitor ocular surface conditions and detect complications early.
Yulia Dyachenko
Published:
Jan 29, 2024 11:40 AM
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