Upcoming Solar Eclipse April 8, 2024
On April 8th, 2024, NASA is anticipating a solar eclipse that will pass over North America, including Mexico the United States and Canada. A solar eclipse is when the moon is passing between the Sun and Earth, and while in passing, completely blocks the face of the sun. During this moment in passing, part of the sky in North America will darken as if it was dawn or dusk. People may be interested in watching this phenomenon but it’s also important to be aware of the dangers of staring directly at the sun. It is imperative to avoid staring at the sun without eye protection as it can cause severe damage to the eyes. There is only a brief moment when the sun is completely blocked, and is safe to look. Furthermore, do not look at the Sun through a camera lens, telescope, binoculars, or any other optical device while wearing eclipse glasses or using a handheld solar viewer because the concentrated solar rays will burn through the filter and cause serious eye injury(1).
Caption: Solar Eclipse glasses with solar filters.
Safe ways to watch the solar eclipse:
1.) Indirect viewing method: Create a pinhole projector. Example: You can poke a pinhole through a cereal box flap and watch the shadow created through the hole against the back of the cereal box as the moon blocks the sun. You can then safely view the projected image created by the sunlight passing through the pinhole.
2.) Direct viewing method: Solar eclipse glasses that meet the Transmission Requirements if ISO 12312-2, Filters for Direct Observation of the Sun. If you don’t have one of these, your best bet is to use the indirect viewing method.
What can happen when you stare directly at the sun?
Looking directly at the sun without proper eye protection can cause serious injury to the retina. Solar retinopathy can be developed and can cause these side effects listed below due to thermal/photochemical damage to foveal photoreceptors (2).
Central scotoma: A blind spot which may be perceived as a persistent dim spot or black spot in the vision.
Blurred vision: A person’s visual acuity becomes worse than 20/20.
Metamorphopsia: A distortion in vision where straight lines appear wavy or missing, larger or smaller compared to normal vision.
While a person’s visual acuity can significantly improve over time, there are reported cases where the scotomas are persistent and may be debilitating.
Author: Dr. Josephine Ko, OD, FAAO
References:
1.) https://science.nasa.gov/eclipses/future-eclipses/eclipse-2024/
2.) Stephenson, K.A.J., Stephenson, G.R., Forristal, M.T. et al. Long-term anatomical and functional findings of solar maculopathy. Ir J Med Sci 193, 435–441 (2024). https://doi.org/10.1007/s11845-023-03434-2