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Millions of people wore special eclipse glasses to watch the solar eclipse that took place earlier this month. If you wonder if looking at the sun directly during an eclipse is safe, the answer is no.

Doctors say staring at the sun for as little as five seconds can damage your eyes. Looking for longer can make the damage permanent.

It is only safe to look at the sun without eclipse glasses during total eclipse. This is a short period of time when the moon covers the sun completely. However, the sun cannot be seen at all through eclipse glasses during total eclipse.

Dimitrios Karamichos, executive director of the North Texas Eye Research Institute at the University of North Texas Health Science Center in the US, said permanent damage to the retina can happen in 60 to 100 seconds or less (see graphic).

This condition is called solar retinopathy. Symptoms include dark or yellow spots, dimmed or blurred vision, and loss of vision in the centre of the eye.

There is no treatment for eye damage caused by the sun. Even if vision improves, some distortion and dark spots may remain.

Those who experience any of the symptoms of solar retinopathy should see an eye doctor immediately.