Usually, people notice symptoms — including blurry vision, discolored spots in vision, pain, or a loss of central vision — by the next day.
If you are experiencing any of these symptoms after staring at the eclipse, call an eye doctor.
Eye doctors are going to be busy on Tuesday.
If you checked out the solar eclipse and weren't wearing certified protective glasses — or even if you were — you might be wondering if your vision is OK.
Looking at the sun without adequate protection allows sunlight, including ultraviolet and near-infrared radiation, to penetrate the retina. That can burn parts of the eye and create a toxic reaction that causes damage, which can lead to a condition eye doctors refer to as photic or solar retinopathy.
If you unsafely watched the eclipse, damage may not be immediately apparent, since you can't feel burns on your retina. Some people might start to notice vision changes within a few hours, though it's most likely they would become apparent by the next day, according to the American Academy of Ophthalmology.
Symptoms of solar retinopathy include poor vision or vision changes including blurry or discolored spots, pain, and especially a loss of vision in the center of the eye. Several people with solar retinopathy report being unable to read because of the changes, which can be temporary or permanent.
2017 total solar eclipse
People watch the solar eclipse on the campus of Southern Illinois University on Monday. Scott Olson/Getty
Some people Business Insider spoke with said their eyes felt strange immediately after viewing the eclipse even though they wore protective glasses. If your glasses were certified and didn't let in any light less bright than the sun, the discomfort may be temporary, caused by the rapidly changing levels of light exposure you encountered while repeatedly covering and uncovering your eyes to look at the crescent sun. Your eyes feeling weird after watching the eclipse doesn't necessarily mean there's any permanent damage.
People who watched the eclipse for even a brief period without protection, however, are susceptible to damage. President Donald Trump briefly demonstrated what you were not supposed to do, and the tech entrepreneur Elon Musk may have done the same, tweeting that he watched with "sunglasses."
Sunglasses don't provide adequate protection and could increase the risk of eye damage, since the pupil opens up wider to let light in, according to Dr. Tongalp Tezel, an expert on retinas at Columbia University Medical Center.
If you are experiencing vision changes or eye pain, even if you wore proper eye protection, call an eye doctor to schedule an appointment.
Many cases resolve themselves over time, within a day or even over a couple of weeks, according to an editorial in the journal JAMA Ophthalmology. But if vision hasn't come back within six months, it's not likely to — and there is, unfortunately, no treatment for solar retinopathy.
A doctor can examine your eye and see changes to the retina, which can take on the appearance of the crescent-shaped sun responsible for the damage. Without medical confirmation, it's hard to know whether something is wrong and can be addressed.
"I always, always say if you notice something strange about your vision, see the eye doctor," Adriane Santa Croce, an ophthalmic sonographer at Scheie Eye Institute in Philadelphia, told Business Insider. She added that "the concerns about vision following the eclipse may uncover unrelated eye problems that people may not have addressed otherwise," including changes in vision related to diabetes, cataracts, macular degeneration, or glaucoma.
Santa Croce said this eclipse should provide doctors with a better understanding of how light can damage the eye, since some current imaging technology didn't exist the last time many people watched an eclipse.
Regardless of how your eyes feel after the eclipse, the AAO recommends regular comprehensive vision exams, since several health conditions can be first spotted in the eye.
If for any reason — eclipse or not — you notice any pain or vision changes, call a doctor to be safe.