The competition for the “honor” of being the most confusing part of clinical trial results is fierce. I don’t think technical terms…
And they would help his myopia … for about half an hour. Wearing them much longer was intolerable.
It was 1889 and August Müller was a 25-year-old medical student in Germany, trying to find something that would work better than his very thick glasses.
He called his invention Hornhautlinsen – corneal lenses. The cornea is the clear outer layer of the eye. It protects the eye and helps focus.
Müller ground his 3 lenses out of blown glass himself. Here they are at the Deutsches Museum. They were the first contact lenses that could correct refractive errors like myopia, and they would go into production in 1909.
But it was another young German, Adolph Eugene Fick, who got the title, “father of the contact lens.” He was an ophthalmologist who published research on what he called Kontaktbrille (contact glasses) in 1888.
Fick’s lenses were made of heavy brown glass, from the bottom of test tubes. He used a grape solution as a buffer between the lens and the eye. That was added after the lens. He pulled the edge of the lens up with a muscle hook and added a few drops underneath.
Fick had experimented on rabbits, then on himself – and then on 6 volunteers. People couldn’t tolerate them for long either. And if he left the lenses in for more than a few hours in the rabbits, their corneas started to get hazy. It was the first sign of the trouble to come.
Contact lens technology took a few big leaps in the 20th century. People started using plastic lenses more widely in the 1950s, but it would be the 1960s before they became comfortable enough to be popular.
Chemists in Czechoslovakia, led by Otto Wichterle and Drahoslav Lím, developed (and patented) a new plastic that were used to make the first thin flexible contact lenses. They published in Nature in 1960.
The first of these soft contact lenses reached the US market in 1971, beginning an ongoing tussle between manufacturers and the FDA over safety and recommendations on how long to wear them.
Still, the risks of sight-threatening infections were widely underestimated at first. It took till the early 1980s for recognition to grow.
It was the very common problems that were noticed first – irritation and allergic reactions to disinfectant solutions cause a lot of contact lens-related conjunctivitis. But it was corneal infections – keratitis – that did serious damage. That can be hard to recover from, leading to hospitalization, and sometimes corneal transplantation and vision loss. And by the mid-1980s it became clear that wearing contact lenses brought some keratitis risk with it.
Meet Acanthamoeba: it’s common in water and usually doesn’t bother us. But in people who wear contact lenses, it can get into the cornea and cause keratitis and damage the eyes. It’s not a common cause of contact lens-rested keratitis, though.
In the late 1980s, an outbreak led the FDA to ban the sale of salt tablets for contact lens use. Then came a mini-epidemic of another usually rare cause of keratitis – the fungus Fusarium – in 2005 and 2006. It started in Hong Kong, and there were over 250 cases reported worldwide with over 160 in the US: a third of the people in the US needed corneal transplants.
Contaminated contact lens solution was a big contributor to that outbreak. This month at an FDA workshop on contact lens-related Acanthamoeba keratitis, Jennifer Cope from the CDC put the 1987 outbreak down to a perfect storm caused by a particularly virulent organism, poor hygiene and changes in lens-cleaning practice. Ingredients in solutions had changed – and there had been a trend to encouraging people to rinse their lenses only, not rub them. Rinsing may not remove enough common deposits (like bits of mascara) – and people take shortcuts.
It’s not easy, convenient or cheap to stick to the hygiene practices you need to reduce the risk of infection – and most people probably don’t, even if they think they’re pretty good at. (Here’s the FDA’s advice on contact lens care.)
The biggest single risk for eye damage, though, comes from wearing contact lenses overnight or longer – and not getting medical attention early enough. Because corneas need oxygen, it had been thought that lenses that let oxygen through would reduce the risk.
But it turns out they didn’t: they may even increase the risk a little. The risk of keratitis is around 2-4 cases for every 10,000 people who wear the common soft contact lenses during the day only, going up to about 20 per 10,000 for longer use (or 1 in 500). Among the people who get it, vision loss has been reported for around 12-14%. That’s a small, but very serious, risk. (Update: The CDC estimates there are close to a million doctor or hospital visits for keratitis associated with contact lenses each year in the U.S.)
And to top it off, if you think using your computer might be bothering your eyes and you wear contact lenses, you’re probably right. The evidence isn’t good enough to put a solid number on it, but contact lenses plus computer use does seem to greatly increase common problems like dry eye syndrome.
I’ve never had the slightest urge to wear contact lenses – I don’t even like putting eye drops in my eyes! I’ve been lucky with my eyes, and I like the slightly blurry way the world looks to me. I quite like popping my glasses on and off, too. They don’t get in the way of anything I want to do. It’s very different for lots of other people, though, and contact lenses for common vision problems are very important for many people’s quality of life. Update: Check out the comments below this post for the positive difference they can make.
But the societal pressure about appearances that partially drive this is troubling.
Harmful stereotypes too, fuel childhood bullying and anti-intellectualism. And it’s there when lawyers discuss the possible impact of stereotypes about glasses in courtroom decisions.
Over 30 million Americans wear contact lenses. There isn’t a gender difference in young people. But as we get older, and more of us need vision help, the gender divide becomes stark. In their 40s, 25% of women who need correction of refractive errors use contact lenses – and only 15% of men. Over the age of 50 wearing contact lenses becomes uncommon, but getting there seems to be harder for women.
Nearly half the American population over the age of 12 report using glasses or contact lenses. Shouldn’t we be getting over the glasses stereotypes by now? Then maybe we wouldn’t need to trivialize the risks of putting devices inside our eyes.
Another Absolutely Maybe post on appearance and stigma: Blemish – The Truth About Blackheads.
CDC guide to healthy contact lens use. Information from the FDA on decorative contact lenses. And last year, the American Academy of Ophthalmology put out a statement of advice for wearing contact lenses longer than a day.
* The thoughts Hilda Bastian expresses here at Absolutely Maybe are personal, and do not necessarily reflect the views of the National Institutes of Health or the U.S. Department of Health and Human Services.