Eye damage can emerge days after unprotected eclipse viewing

Eye damage after watching Wednesday’s partial solar eclipse without adequate protection may not become apparent immediately, SRF reports. Symptoms can include a shadow or central spot in the field of vision.

Prof. Nicolas Feltgen, chief physician at the Basel Eye Clinic, said the focused sunlight can heat the retina and cause swelling of the retina and photoreceptors. The severity of the shadow or spot depends on how long a person looked at the Sun without protection.

The condition, known as solar retinopathy, involves a small burn to cells in the macula, the part of the eye responsible for sharp vision. Because the retina has no pain receptors, damage can occur without being noticed straight away.

The dominant eye is often affected, Feltgen said. The shadow may become smaller as the swelling subsides, which can take one to two weeks. However, residual damage is not uncommon, and deeper injuries can cause permanent loss of vision.

Anyone experiencing symptoms should see an eye specialist, according to Switzerland’s Federal Office of Public Health. Feltgen said an examination is important while the injury is still recent and because other conditions with similar symptoms may be treatable.

There is no proven treatment for solar retinopathy. Trials involving cortisone have been conducted, but there is no evidence that the treatment works.

Looking directly at the Sun is dangerous even during a partial eclipse. Although the Moon blocks part of the Sun’s surface, the light intensity in the visible areas remains just as high. Safe viewing requires an undamaged, CE-certified protective filter meeting ISO 12312-2:2015.