On Monday, millions of people will be treated to the first full solar eclipse of their lives.

Without safe viewing practices, however, those millions could potentially be seeking medical attention by Tuesday.

Dr. Cindy Ellenbecker of Ellenbecker Eye Clinic in Riverstone has been working for the past several months educating her patients and the public with posts on the clinic’s Facebook page. The business has also handed out about 500 pairs of solar glasses. Ellenbecker is hoping with all that information, people will know enough to not hurt themselves.

“If people aren’t sure, even with the eclipse glasses, there’s no need to stare,” she said. “You can glance and look away, you can see what’s going on, you can look at the environment around you, you can experience how it gets dark. There’s no need to stare for two hours right at the sun.”

The sun is said to be 400,000 times brighter than a full moon and emits harmful UV and IR radiation. Any amount of direct sun exposure to the eyes may cause long-term damage. This is called solar retinopathy, which is essentially burning of the retina and damaging or destroying its cells.

“It is a little burn right in the center of the retina that you can see, and it’s permanent,” Ellenbecker said. “The person wouldn’t be technically blind, but they would have a blind spot right in the center of their vision.”

There’s no treatment or cure for solar retinopathy, she added. The damage may or may not be painful, and the blind spot symptom can be immediate.

The American Astronomical Society, the American Academy of Ophthalmology and NASA recommend people use only eclipse glasses that are rated by the International Organization for Standardization (ISO) with a number 12312-2, (sometimes written as ISO 12312-2:2015), which indicates the lenses will block out 99.99 percent of the sun’s rays. But with high demand for these glasses, there have been reports of fraudulent glasses being distributed, with counterfeit safety labels on them. Amazon has recently been tracking down glasses that may not comply with ISO standards and is issuing refunds to those who may have bought them.

An ASA task force has been compiling a list of trustworthy manufacturers and vendors of safe glasses. They recommend that even if a pair has the proper ISO number and safety stamp, you should refer to the list to be sure you have an authentic pair by searching for the manufacturer’s name and address, which should also be included on every pair.

To test a pair that you may be unsure of, use a bright light source like sunlight reflected in a mirror or off a shiny object; the hot filament of an unfrosted incandescent bulb; a bright halogen bulb; a bright white LED bulb; or an arc welding torch. These points of light should appear dimly through the glasses. If you are able to see light from a dimmer source through the glasses, such as light through a lampshade or a frosted bulb, you may have a bad pair. A good pair will have a comparable brightness as that of the moon seen with the naked eye.

As glasses are becoming harder to come by as the big day draws near, many people have been planning on using welding goggles to safely view the eclipse. This is only safe if they are rated at shade 12 or higher, although some sources claim that 14 is the only safe level, experts say.

What absolutely isn’t safe are dark or polarized sunglasses, 3D glasses, or cameras, telescopes or binoculars with unfiltered lenses. Photographing the eclipse should be done only by someone with extensive photography knowledge and proper equipment. Solar lenses must always be attached to the front of any camera to prevent damage to the equipment and accidental exposure to your eye. Don’t think you will be safe by wearing a pair of eclipse glasses while using anything with unfiltered lenses, as the sun’s rays will actually be amplified and penetrate the film of the glasses. Be sure to cap or remove an auxiliary finderscope if your camera has one, and ensure lenses are secured well to avoid detaching while in use.

To learn more about eclipse viewing safety and to see the list of reputable glasses manufacturers, visit: eclipse.aas.org