Doctors warn against viewing solar eclipse without protection

Yle reports that doctors are warning people not to look directly at Wednesday evening’s partial solar eclipse without proper eye protection. The sun can permanently damage the retina, potentially impairing the sharp vision needed for reading and driving.

Ordinary sunglasses are not sufficient. Viewers should use special eclipse glasses or number 14 welder’s glasses.

“If you look directly at the sun, the retina can be permanently damaged,” said Matti Seppänen, chief ophthalmologist at Terveystalo. The sunlight can irreversibly damage the light-sensitive cells in the retina.

The damage can affect central vision, while peripheral vision is often preserved. In severe cases, an object may disappear from the centre of a person’s field of vision or become significantly blurred. The damage may not be noticed until several hours after exposure.

During an eclipse, the sun appears less dazzling than usual, which can lead people to stare at it even though the amount of harmful energy reaching the eyes remains substantial. Because the eclipse will be visible in Finland in the evening, lower light levels may also cause the pupils to dilate and allow more light to reach the retina.

Jussi Paterno, an ophthalmology specialist at Kuopio University Hospital, said there is no safe exposure time that can be given. Some sunlight-related damage may heal over weeks or months, but not all injuries recover.

Paterno said the sun’s energy can cause a thermal burn in the eye. He has treated patients after previous eclipses and described the injuries as a genuine but largely preventable problem. There is no effective treatment, although inflammation caused by an injury is sometimes treated with cortisone. There is not strong research evidence for its effectiveness.

Ursа, Finland’s astronomical society, says a high-quality filter or filter film must be placed in front of a telescope’s eyepiece when viewing an eclipse. The same type of protection can be used for a camera lens. Without it, the camera sensor may be destroyed.

Paterno advises against observing the eclipse through binoculars, telescopes or a camera’s viewfinder unless the person is an experienced amateur or professional. Incorrectly chosen or poorly attached filters could direct a large amount of sunlight into the eyes. When taking pictures with a mobile phone, sunlight can also reach the eyes around the edges of the device. Paterno recommends photographing the eclipse in selfie mode with your back to the sun.