Researchers at Linköping University in Sweden studied 132 people who had previously experienced mild COVID-19.
Using specialized eye examinations and tear fluid analysis, they identified changes that cannot be detected through a standard eye examination.
The findings were published in the journal Nature Communications and reported by HealthDay.
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The study found signs of inflammation and damage to the nerves that help the eye function.
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Researchers also identified abnormalities in the pupils' response to light and in the control of the eye muscles.
For some participants, the symptoms were severe enough that around one in three people with symptoms were fully or partially on sick leave from work, according to the study.
Explaining the problems
The study suggests that these hidden changes may be responsible for eye pain, light sensitivity, reading difficulties, and difficulty focusing.
At the same time, the findings help explain why many patients continue to experience symptoms even though a routine eye examination appears normal.
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The researchers hope that these findings will make it easier to provide the correct diagnosis and, in the long term, lead to better treatment for people with persistent eye problems following a mild COVID-19 infection.
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