SALT LAKE CITY — Those wanting to view the 91 percent eclipse in Utah on Monday should do so with caution, said Dr. Jeff Pettey, Moran Eye Center ophthalmologist.
Looking directly at the sun without proper eye protection can cause permanent vision damage, Pettey said. He compared the potential damage to the blurry vision caused by looking at a flash when a photo is taken — only permanent.
Pettey suggested thinking about the eye as a magnifying glass.
"All the light coming into the pupil is going to focus on one point in the back of the eye, and that’s the point where you see this damage," he said. “The intensity of all the light's rays (is) focused on that one spot, and that’s where the tissue damage occurs.”
But there are precautions Utahns can take to avoid that potential damage without buying special glasses, Pettey and Clark Planetarium Director Seth Jarvis told reporters Tuesday at the planetarium.
The easiest and most affordable option, Jarvis said, is called a "pinhole projection," which lets sunlight pass through a small opening — like a hole punched in a piece of cardboard or an index card — and projects an image of the sun onto a flat, blank surface.
Eclipse watchers also can use tree leaves, crackers or other objects with small holes in them to project sunlight onto a surface, he said.
"There's suddenly a million pinhole projectors through nature,” Jarvis said.
Utahns who want to look directly at the sun to view the eclipse should use ISO-certified glasses, Jarvis and Pettey said.
Unfortunately, Jarvis said, counterfeit glasses are being sold on the internet without actually being ISO certified.
“Anybody that knows how to run a printing press … can print whatever they want," he said, which is why it's important for those buying glasses to look for more than the ISO logo.
The best way to make sure glasses are safe for the eclipse is to look for the manufacturer's name and contact information on the glasses or packaging material, Jarvis said.
"There’s no way of knowing whether these glasses are passing through harmful levels of infrared radiation, which is going to bake your eye," he said. "If the glasses are anonymous, I would chuck them."
The Moran Eye Center this week issued a recall on glasses it was originally selling. Now, the University of Utah eye clinic is carrying glasses manufactured by Lunt Solar Systems, emblazoned with the Clark Planetarium logo.
"What we’re asking of people is to not use any pair of glasses that they have received from Moran Eye Center unless they have the Clark Planetarium label," said Elizabeth Neff, spokeswoman for the center. "Your vision is precious, and it's just not something to take a risk with."
Jarvis said he encourages everyone to take advantage of the near total eclipse on the Wasatch Front, an event he said will not occur again until 2045.
"We want you to pay attention to this wonder of nature, this celestial show of the moon passing in front of the sun," he said. "It’s pretty cool stuff."
In addition to Lunt Solar Systems, reputable companies selling eclipse glasses include American Paper Optics, Celestron, DayStar, Explore Scientific, Halo Solar Eclipse Spectacles, Meade Instruments, Rainbow Symphony, Seymour Solar and Thousand Oaks Optical, Jarvis said.
Clark Planetarium is selling the glasses for $2, though Jarvis expects to be sold out by Thursday.