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Dr. Patricia Bath: Seeing the Light

How a visionary inventor created a cure for blindness

Patricia Bath with laser equipment
Portrait of Dr. Patricia Bath, by Weilu Shen

It’s usually a terrible idea to shine a laser into your eye, but doctors actually use special lasers in eye surgery all the time. They can use lasers to precisely change how parts of your eyeball are shaped so that you no longer need glasses to see clearly. But thanks to the inventions of Dr. Patricia Bath in the 1980s, they can also be used to cure a common cause of blindness.

"Countless numbers of people have gotten their sight back thanks to Patricia Bath’s visionary work in vision."

Watch the video or read more below!


I spy with my little eye...

Diagram of the parts of your eye, which work together to help you see!

Your eye is made up of a lot of parts, including the cornea (the outside covering of the eye), the pupil (which lets in light), and the lens, which focuses that light onto the retina (the back of the eye) so that your brain can interpret the image that you see.

The lens is one of the most important parts of the eye, and if you’re wearing glasses or contact lenses right now, it’s because the lens of your eye is misshapen in some way, making it hard for your eye to properly focus the light coming in. And if that lens becomes opaque or cloudy due to unwanted clumps of proteins floating around in it, then less and less light is able to pass through. Eventually, this cloudiness, called cataracts, can be so bad that no light can get through at all and the person becomes blind. Dr. Bath’s invention uses lasers to treat those cloudy, light-obstructing cataracts!

Diagram of normal eye and eye with cataracts
Cataracts can eventually cause blindness if they're not treated

Cataracts are unfortunately super common, especially for older people. Half of all cases of blindness worldwide are caused by cataracts– almost 20 million people. Because this condition is so common, humans have been trying to figure out how to treat it for a really long time. Early surgeries to remove cataracts were performed all over the world:

Timeline of India, Greece, and Egypt
Timeline of where in the world people developed early treatments of cataracts

in India in 400 BCE, in Greece in 200 CE, and in Egypt in 1000 CE. These surgeries were really dangerous, and patients often died from infection or complications. Even with better modern surgeries to remove cataracts, there’s still an epidemic of preventable blindness in some underserved communities in the US and worldwide from lack of equal access to healthcare.


An active activist

These are the kinds of issues that Dr. Patricia Bath wanted to solve when she became an ophthalmologist (eye doctor). Patricia grew up in Harlem in New York City and had a long interest in medicine. When she was in high school, she spent a summer researching cancer growth and developing mathematical equations to describe the disease, which she published when she was only 18 years old.

But Patricia wasn’t just interested in medicine for the science; she wanted to help the people who needed it the most. When she was in medical school at Howard University in 1968, she learned that Dr. Martin Luther King Jr. had been assassinated. She wanted to do whatever she could to support Dr. King’s fight for civil rights, so she got a group of med students to travel with her to Washington, DC, where she spent the summer providing volunteer medical services to activists who were protesting for economic equality.

LEFT: People walking in Harlem in NYC in 1942, the year Patricia Bath was born. Photo from National Archives- Hulton Archive/Getty Images. RIGHT: Protestors and activists marching for economic justice in Washington DC in 1968. Photo from Hulton Archive / Getty Images.

Once Dr. Bath graduated from medical school in the 1970s, she started thinking about ways that she could make the biggest impact on improving eye health, especially for underserved communities like the Black neighborhoods she grew up in. Her research focused on developing safer treatments for cataracts, using a pretty new technology: the laser.


Lasers aren't just in sci-fi

Diagram of laser shining in eyeball to remove cataract
Laserphaco uses a UV laser to burn away the cataract so the patient can see

The first working laser had been built only 30 years before, but Patricia Bath had the idea of using this new technology to burn away the cataract blocking vision, allowing the doctors to replace the diseased lens with a new, artificial lens. She called this procedure Laserphaco, short for PHotoAblative Cataract Surgery. The word “ablative” means removal by evaporation, so this name is short for the idea that the laser light (photo) is burning away the diseased lens.

Don't shine that in your eye!

You may have already heard to be careful around lasers, but what makes lasers different from the kind of light that shines in your eyes every day? For one, lasers can be super powerful, way more bright than the light coming out of your lamp or phone. But the other special thing about lasers is that they’re made up of just a single wavelength of light, with the light waves all lined up and parallel with each other. And if that wavelength is in the visible or infrared parts of the spectrum, then your eye is really good at focusing those wavelengths so that you can see them. Unfortunately, when it’s laser light, then your eye is TOO good at focusing it, and all the power is concentrated on one tiny spot in the back of your eye, which can be permanently burned and blinded!

And if that light is in wavelengths that you can’t even see, there’s an additional level of danger. If the light is UV for example, and too high frequency for our eyes to detect, we won’t have the instinct to blink and protect our eyes. This can lead to UV lasers causing photochemical damage, which is a fancy way of saying sunburn on your eyeball. But this same property that can cause UV sunburn is what Patricia Bath used when she invented Laserphaco. Dr. Bath’s invention uses the fact that UV lasers can burn your eye to intentionally burn away the diseased part of someone’s eyeball, without any scalpel or knife!

A visionary leader

Patricia Bath looking through a microscope
Patricia Bath using a microscope to perform a delicate operation. Photo by Eraka Bath

Patricia’s idea was brilliant, but it was also a really advanced application of lasers at the time. In fact, it was so groundbreaking that Dr. Bath had to spend 5 years just developing the technology. To do so, she would run experiments, adjust the design, and even practice on human eyes from an eye bank - collections of donated human eyes! But in 1988, she cracked the process and patented her new invention, becoming the first ever Black female doctor to patent a medical device. It’s crazy to think of how fast this technology developed. The very first laser was built in the late 1950s, and by the late 1980s, thanks to Patricia Bath, they were precise enough to be used for delicate surgeries in human eyes!

Dr. Bath wasn’t just a doctor, she was also an inventor, activist, and humanitarian. In addition to the 5 patents she held for cataract treatment, she also traveled around the world performing surgeries for people who didn’t have access to the healthcare they needed. Dr. Bath was incredibly proud of this work, including a surgery she performed for a woman in Northern Africa which restored her sight after 30 years of blindness.

As Dr. Bath once said,

“When we would play nurse and doctor, I didn’t want to be forced to play the role of the nurse. I wanted to be the one with the stethoscope, the one who gave the injections, the one in charge.”

This drive and ambition can be seen in her leadership in community-focused ophthalmology and her incredible inventions. Countless numbers of people have gotten their sight back thanks to Patricia Bath’s visionary work in vision.

Written by Caroline Martin

Edited by Madelyn Leembruggen

Illustrations by Lindsey Oberhelman

Portrait by Weilu Shen

Sources and additional readings:

Patricia Bath from Wikipedia


Explore the eye-opening world of vision

Experiment (20-30 minutes): Your eye has a lens inside it that focuses the light down so you can see properly. Play around with this simulation of how a lens bends and distorts light, and figure out if you can make an optical system that focuses light like your eye does!

Learn (15-20 minutes): Watch a video of someone dissecting a cow's eye to learn about the parts of the eye and how they all work together. Warning: this video shows the full dissection and is therefore pretty graphic.

Test (15-30 minutes): Your eye is an incredible development, but a lot can go funny with your vision. Try out these at-home experiments to find your eye's blindspot and to test to see if your eyes have astigmatism.


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