Why is it dangerous to look directly at the Sun during a partial solar eclipse?

Looking directly at the Sun during a partial solar eclipse is dangerous because the Sun remains extremely bright, even when a large percentage of its disk is obscured.1

The primary risks include:

• Pupil Dilation: As the sky darkens during an eclipse, your pupils naturally dilate, allowing more light to enter the eye.1
• Lack of Pain Receptors: The retina lacks pain receptors, meaning you will not feel damage as it occurs. Symptoms often do not manifest until hours or days later.1
• Solar Retinopathy: Exposure can lead to solar retinopathy, which may cause blurred vision, altered color vision, or permanent loss of central vision.1

Children are especially vulnerable because their eyes allow more light to reach the retina. To view an eclipse safely, you should use eclipse glasses that conform to the ISO 12312-2 standard or use indirect viewing methods, such as projecting an image of the Sun onto a surface. Never use ordinary sunglasses or look through optical devices like binoculars or telescopes without certified solar filters.12