Dry eye is a common eye condition in which the surface of the eye is not sufficiently moisturized and also becomes inflamed. Typical symptoms include burning, redness, foreign body sensation, itching and rapid eye fatigue. An inflammatory messenger substance called MMP-9, which can damage the surface of the eye, plays a central role.
This study investigated whether sterile isotonic seawater can effectively reduce this inflammation. All study participants suffered from dry eye and showed increased MMP-9 levels in the tear fluid. For three weeks, they exclusively used an isotonic seawater spray for the eyes.
The result: in a large proportion of the eyes treated, the inflammation was significantly reduced or even completely suppressed. The previously elevated MMP-9 levels decreased and many patients reported noticeable relief of their symptoms.
The seawater was very well tolerated and there were no side effects.
Conclusion: Isotonic seawater can effectively reduce the inflammatory processes in dry eyes and is a well-tolerated alternative or supplement to classic artificial tears.
Background
Dry eye is a chronic, inflammatory disease of the ocular surface. In addition to a reduced quantity or quality of tears, inflammatory processes play a decisive role in the course of the disease. One of the most important inflammatory markers is matrix metalloproteinase-9 (MMP-9), an enzyme that attacks the protective barrier of the cornea and contributes to the chronification of symptoms.
Conventional therapies such as artificial tears primarily improve moisturization, but only have a limited effect on inflammation. The aim of this study was therefore to test whether isotonic seawater has a direct anti-inflammatory effect on the ocular surface.
Study design
The investigation was conducted as a prospective clinical study. Patients with mild to moderate dry eye disease in whom a standardized rapid test detected elevated MMP-9 levels in the tear fluid were included.
Over a period of three weeks, all participants exclusively used a cold, microfiltered isotonic seawater spray, which was applied several times a day. Other eye drops or anti-inflammatory medication were not permitted during the study.
The inflammation markers were measured again before and after the treatment phase.
Central results
Reduction of MMP-9
After three weeks, a significant proportion of the eyes showed a normalization of the previously elevated MMP-9 levels. This indicates a direct reduction of inflammation on the ocular surface.
Improvement of the inflammatory situation
Since MMP-9 plays a key role in corneal surface damage, its decrease indicates a stabilization of the ocular surface and an interruption of the inflammatory vicious circle.
Very good compatibility
No side effects occurred during the entire duration of the study. The seawater was tolerated by all participants without any problems, even with frequent use.
Possible mechanisms of action
The authors attribute the anti-inflammatory effect to several properties of seawater:
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Lower sodium content compared to saline solution
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High content of magnesium, potassium, calcium and bicarbonate, which have an anti-inflammatory effect
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A slightly alkaline pH value that relieves irritated mucous membranes
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Mechanical cleaning effect that removes inflammatory substances from the surface of the eye
This combination distinguishes seawater fundamentally from conventional saline solutions or purely moisturizing eye drops.
Classification of the results
The study shows that isotonic seawater not only has a symptom-relieving effect, but also influences biochemically measurable inflammatory processes. The observed effect is comparable to the reduction of MMP-9, as described for anti-inflammatory drug therapies – but without their potential side effects.
Restrictions
The duration of treatment was relatively short, so that no conclusions can be drawn about long-term use. The authors therefore recommend further long-term studies.
Conclusion
Isotonic seawater is a safe and effective option for the treatment of inflammatory dry eye. It can lower elevated MMP-9 levels, reduce inflammatory processes and stabilize the ocular surface.
The study provides a solid scientific basis for the use of seawater as a functional, inflammation-modulating therapy for dry eye.