Eye flu, which is medically correctly called keratoconjunctivitis epidemica, is an inflammation of the conjunctiva and cornea of the eye caused by adenoviruses. It lasts about four weeks and is the most common viral disease of the eye, easily transmitted and very contagious. Some patients develop what is called nummuli from the eye flu, which limits vision for a longer period of time.
What is eye flu?
If infection with creatoconjunctivitis epidemica has occurred, there is initially a worsening foreign body sensation that originates from the corner of the eye near the nose. Often, the lymph nodes in the neck are thickened. As the disease progresses, the eyelids swell. The eye reddens and begins to water. In addition, there is pronounced itching, sensitivity to light and deterioration of vision. After two days, at the latest after a week, the other eye is also affected. Usually mild – some patients do not even notice the infection of the second eye. If the cornea of the eye is affected by the inflammation, nummulia may develop. These limit vision and exacerbate the patient’s particular sensitivity to light.
Causes
Eye flu is caused by adenoviruses of types 8, 19, and 37. These viruses are particularly resistant even outside the host body and are capable of spreading the disease for a long time. Keratoconjunctivitis epidemica is therefore notifiable. Since ocular flu is a highly contagious smear infection, spread occurs easily via door handles and other surfaces. The risk of infection is particularly high in public places such as schools, indoor swimming pools or care facilities – or when going to the doctor. Eye flu also spreads from person to person, for example through tear fluid or via the hands. It affects all age groups and can occur at any time of year.
Symptoms, complaints and signs
The first symptoms of eye flu appear very suddenly after an incubation period of approximately two weeks. At first, the patient does not notice anything about the infection. However, the symptoms then appear as if out of nowhere. The eyeball reddens, the conjunctiva swells and the eyes begin to itch and water. In addition, there is severe eye pain. In the further course the complaints increase more and more. The vision becomes more and more blurred. In very rare cases, it can also lead to permanent vision damage. In addition to these symptoms, flu-like symptoms may also occur. These manifest themselves like a common flu-like infection with fever, aching limbs, headache and fatigue. The triggering adenoviruses are highly infectious and long-lived. They can survive for weeks on various objects and can still be transmitted afterwards. Only through strict hygiene measures such as frequent hand washing and disinfection measures is it possible to reduce the risk of infecting family members and other contacts. Once the eye flu has broken out, there is no treatment option that will lead to a faster recovery. Only the symptoms can be alleviated with cooling compresses and eye drops. As a rule, the symptoms subside on their own within two weeks. Because of the high risk of infection, the patient should stay at home for two to three weeks.
Diagnosis and course
The ophthalmologist makes the diagnosis based on the visible signs of the disease. These usually develop within a few hours. Usually, nucleic acid detection is also used as a diagnostic tool. Rapid tests are not as reliable as laboratory results. The course of the viral infection may be accompanied by aching limbs and a feeling of weakness. From the fourth day after the first signs of illness, inflammation of the cornea may occur. If it is affected, this is initially manifested by small, punctiform changes. These gradually become larger. After the acute phase, they may develop into nummules: Round opacities in the cornea that lead to a decrease in visual acuity and increased sensitivity to light. It may take several weeks and months for the nummuli to completely disappear. The acute phase of ocular flu heals within three to six weeks. Some patients subsequently experience eye dryness, which requires treatment.
Complications
The main clinical symptom of keratoconjunctivitis epidemica, known as eye flu, is inflammation of the conjunctiva. Adenoviruses invade the mucous membranes of the eyes, causing redness and inflammation without prior signs. The upper and lower eyelids are swollen, and the lymph nodes in front of the ears are usually affected as well. Patients complain of a foreign body sensation in the eyes, but vision is not affected. These symptoms are accompanied by heavy tearing and some sensitivity to light. The inflammation causes drooping lower eyelids in most patients. Every second patient is also affected by corneal inflammation after four weeks. The eye flu runs predominantly without complications and is well to be treated with appropriate medicines, so that the patients do not have to fear late consequences. In rare cases, conjunctivitis spreads to the throat, upper respiratory tract, lungs, gastrointestinal tract and liver. In the worst cases, inflammation of the brain and meninges can occur. However, these severe complications occur extremely rarely if treatment is not given or is given too late. Adenoviruses are very resistant and are found everywhere in the environment of the sick person. Characteristic of eye flu is therefore the extraordinarily high rate of infection. Waves of infection regularly occur in the home, schools and kindergartens. In the form of nosocomial infection in hospitals, keratoconjunctivitis epidemica is notifiable.
When should you see a doctor?
If you have eye flu, you should definitely see a doctor. The eye flu itself can have a severe negative impact on the person’s ability to see and, in the worst case, can lead to blindness or other irreversible damage to the eyes. For this reason, early diagnosis and treatment is very important. As a rule, the doctor should be consulted when there is a foreign body sensation in the eye and when the eyes are clearly swollen. Furthermore, the eyes are not infrequently reddened and may itch or water. In most cases, the symptoms last for several days and do not disappear on their own. A sudden loss of vision or a strong sensitivity to light can also be a sign of eye flu and should be examined in any case. Furthermore, the eye flu also leads to a general feeling of weakness and fatigue and not infrequently also to aching limbs. It can also inflame the cornea and cause further discomfort to the eyes. Eye flu should be treated directly by an ophthalmologist.
Treatment and therapy
The acute symptoms of the disease are treated with tear substitutes. In very severe cases, antibiotics are given to prevent the infection from worsening. There is no treatment option for ocular flu itself. However, different research results are available that open up possibilities for supportive therapy. One option that has been shown in animal studies to partially decrease viral counts and thus reduce transmissibility and exacerbation of the disease is glanciclovir. It can be applied as a gel to the eye. Administration of ciclosporin A eye drops in another animal trial reduced the incidence of severe corneal opacities but had an unfavorable effect on surrounding tissue. Application of antimicrobial providone-iodine in gel form or administration via eye drops was well tolerated in a small clinical trial and resulted in shorter disease duration. In addition, patients did not develop as many nummulia and viral concentrations decreased. Treatment of nummulia that remain after the actual keratoconjunctivitis epidemica has resolved presents a problem. Here, the physician can administer steroid eye drops. This improves the symptoms, but often causes them to return when treatment is stopped. Also, the virus remains active longer. In addition, side effects and steroid dependence may develop. Alternatively, the use of a calcineurin inhibitor can be tried, which has resulted in slightly improved vision and decrease in symptoms in some subjects. Administration of drugs that reduce immune system activity is also an option. The reason for this is that nummuli consist of immune complexes (a mixture of antigens and antibodies).If nummuli persist after several months despite this treatment, surgical ablation by laser treatment is an option. This can help improve vision, but is not without risk.
Outlook and prognosis
Normally, a very good prognosis can be assumed for eye flu. Although the disease is very contagious and causes numerous symptoms, there are well-tested and proven treatment options that lead to relief of symptoms within a short time. In addition, they cause the patient to be considered completely cured within a few weeks. A delay in the healing process may occur in patients who do not seek medical care or who have an intolerance to antibiotics or eye drops. Nevertheless, even in these patients it is true that they will eventually be cured. Self-healing or alternative options require more time for the recovery process. Despite all this, the eye flu will also lead to the patient being free of symptoms. The stronger the immune system of the ill person is, the faster and better is the healing prospect. During the therapy the appeared impairments gradually regress until they disappear completely. Regardless of the good prognosis, the eye flu can recur in the course of life and cause the same symptoms. Recurrence is possible at any time, as there is no way to protect against the pathogens for life. A new outbreak of the disease is treated according to the same guidelines. The markedly good prognosis also applies here.
Prevention
Proper hand washing is an important measure. Disinfecting surfaces and hands is also helpful. In one study, interferon eye drops have been shown to help prevent infection, for example, if one has occupational contact with people with the disease. Patients with keratoconjunctivitis epidemica should also be isolated because they can infect other people up to two weeks after the onset of the disease in the second eye.
Follow-up
Only adequate hygiene will protect against eye flu. Persons should therefore never touch the eye area with unwashed hands. This is because the pathogens reach the visual organ and trigger the typical symptoms. If several people live in the same household, patients should always use their own towel and change it regularly. To date, there is no effective remedy for eye flu. Once it has subsided, there is by no means immunity. Rather, the disease can occur again and again. Pathogens are often transmitted from person to person. Even shaking hands can lead to infection. Busy places also pose a risk. In buses and streetcars, the pathogens are transmitted imperceptibly via the grip surfaces. In severe cases, several doctor’s appointments are sometimes necessary. There, it is checked to what extent the inflammation is subsiding. Cooling compresses have proven effective in preventing complications. Eye drops can accelerate recovery. Tear substitutes soften the attack on the conjunctiva. The eye flu heals completely after two to four weeks. No further restrictions are then present.
What you can do yourself
Keratoconjunctivitis epidemica as an infectious inflammation of the conjunctiva runs unpredictably. The eye flu, which has many similarities with the real flu, has no causal cure. Those affected must therefore wait for a spontaneous cure, but can help themselves with simple remedies during the period of illness. A mitigation of the symptoms can be achieved with cool compresses. The compresses pleasantly cool the eye area and provide relief from swelling and inflammation. Since eye flu is associated with inflammation of the conjunctiva, various tear substitutes can provide relief during the acute phase of the illness. Ocular flu spreads via smear infection and is highly infectious. For this reason, those affected should place great emphasis on preventing the spread of infection. In everyday life, hygiene measures, above all disinfection of hands, are indispensable. Infectiousness exists within a period of 14 days after the onset of the disease. In order to protect one’s environment, increased attention should be paid to appropriate hygiene during this period, including isolation of the affected person if possible.The towels of the affected person should also not be used by other people. As the body is struggling with the inflammation on the eyes, physical rest is recommended. In most cases, the inflammation subsides within two weeks even without therapy.
