Doctors are shedding new light on a hidden eye condition that can develop after even a mild case of COVID.Researchers say a growing number of patients are experiencing severe eye pain, light sensitivity, trouble reading and difficulty focusing months—or even years—after infection.Yet routine eye exams often appear normal.In a new study, researchers used high-powered microscopes to compare the eyes of 132 people who had mild COVID—the majority with lingering eye problems.They also conducted advanced testing on tear samples.Among those with eye symptoms, they discovered ongoing inflammation and damage to nerves that control multiple eye functions.They also found some patients' pupils were letting in too much light, while others developed an unusual form of crossed eyes, suggesting problems with eye muscle control.The symptoms were so severe, one in three patients reported being on full- or part-time sick leave.The lead researcher says, "These people are really struggling in their daily lives. Now we know what's wrong with their eyes, and have several clues as to how COVID-19 may have caused these problems."The authors hope these findings lead to better diagnosis and effective treatments.Source: Nature CommunicationsAuthor Affiliations: Linköping University Hospital Eye Clinic, Linnaeus University .Sign up for our weekly HealthDay newsletter