Milkweed sap in human eyes is extremely painful and blurs vision for two or three days.

The worst part is that it normally takes hours for eyes to feel the pain and for you to know that there is a problem. By then, you’re on the computer, washing dishes, or doing some other chore. You wonder – what did I just touch? Your mind doesn’t wander back to three hours ago when you cut milkweed leaves. Few doctors have a clue that milkweed sap can cause eye problems. People have this problem and often never realize what caused the issue.
If you do suspect milkweed sap in your eyes, go to a doctor. Do not try to drive yourself. Your vision will become so impaired that you probably will NOT be able to see a car right in front of you or even tell the road from the grass or sidewalk. If sap is splattered directly into an eye, we are told that permanent damage can occur. The sap causes swelling of the retina. The doctor will rinse your eyes and normally place a pain killer in your eyes. He/she may give you a medication to reduce the swelling in your eyes. But he/she (most likely) will not send you home with a prescription or with painkiller to continue to use.
Stephen is well known for cutting milkweed in the greenhouses and wiping his forehead with his hands. Sweat runs the sap into his eyes. These photos are from only small amounts of sap in his eyes. If sap goes directly into the eye, the eye will normally turn as red as a stop sign.

Disposable gloves are inexpensive and found in any pharmacy department. When cutting milkweed, we encourage you to wear gloves. As soon as you are through, take off the gloves, turning them inside out as you do so. Throw them away. It is well worth the price of gloves to avoid even one episode.
OUR PERSONAL EXPERIENCE: (your experience may differ greatly)
For us, pain will increase for a few hours.
Vision gets so bad that we cannot watch a movie and know what is going on. We cannot read a computer screen or a book. My husband cannot tell me and my daughter apart from a distance of 15 feet (and I’m much older and heavier).
Light is extremely painful and we avoid it for two days. Driving is not safe for three days.
For us, ibuprofen helps control and/or eliminate the pain. Do not take any medication without consulting a doctor first.
So – just be careful! Wash hands well after handling milkweed. For your caterpillar’s sake, wash hands well BEFORE handling milkweed too.
Cherie Fite gave us permission to share her story. You can find it here and below.
“Milkweed – Beautiful and Dangerous
November 30, 2013
Milkweed is a beautiful plant with beautiful flowers. It is the life source and host plant for both the Monarch and Queen butterflies. But this beautiful plant requires care in handling. It produces a milky white sap which can be irritating to the skin, but can also be very dangerous if it gets into the eyes.
I have heard many horror stories of people who have had the unfortunate luck of getting milkweed sap into their eyes. Their stories have always served as a caution to me. I am very careful to wash my hands after handling this plant, but even being careful, accidents can happen.
I suppose handling milkweed is one of the hazards of butterfly gardening. I now have my own story to tell. Just last week, I was feeding my Monarch caterpillars freshly washed milkweed leaves. A hair brushed across my eyelashes and without thinking, I wiped it away. My hands were not loaded with sap, but the minute reside on my hands was still enough to begin the chain of events.
I continued to feed my caterpillars and within moments I realized what happened. My eye began to burn, so with one eye closed, I finished feeding my caterpillars and headed off to the bathroom to wash my hands and flush my eye.
I didn’t think my reaction would be too bad because it would have only been trace amounts of sap on my hands, and it wasn’t directly in my eye. But I guess as my eye began to water it spread the toxic sap. The burning pain set in almost immediately. I flushed my eye for about 15 minutes but other than removing some of the irritant, it did nothing for the burning feeling.
The burn and pain from the sap in my eye continued to progress over the next several hours. And it got so bad it was near impossible to open my eye. I took ibuprofen for the pain, but it really did nothing to help. The burning pain continued as severe itching set in. The scariest part was a few hours later when my vision began to change. The room looked smoke filled through my affected eye and all light sources developed rainbow like halos. As the evening progressed, shapes and figures disappeared from my sight. I was very startled that I was unable to even see my 150 gallon fish tank on the wall. It was like it vanished into the smoky room.
Peak pain set in about 12 hours after the incident. I cannot even begin to explain how severe the pain was. It felt as if my eyeball was being dissolved. I have had many incidents where I have gotten things in my eye, but milkweed by far has been the worst.
The following morning, I called my ophthalmologist who saw me right away. Upon examining my eye for the toxic burns, he was very concerned about the amount of swelling to my cornea. In fact, he said it was the most swelling he had ever seen without cornea detachment. I almost had to giggle a little because i felt like i was a medical marvel as three different doctors came in to view the severity of the swelling. When he tested my visual acuity in the eye, I was 20/200. For those who are not aware, that is legally blind. He prescribed a series of corticosteroids, antibiotics, and pain killers for my eye.
The medication worked like a charm, they were like little drops of miracles in a bottle. It provided instant relief from the pain, and reduced the cornea swelling fairly quickly. Within about 12 hours of medication, much of the redness had reduced, and my vision was slightly improved.
It took about a week for me to recover from the incident, although I do still have a lot of light sensitivity in the eye. But that is expected to resolve in the next few weeks.
I wish I had been able to get a good photo during the first 24 hours, unfortunately holding my eye open to do it proved to be impossible. The photo here is 12 hours after beginning the treatment regimen, and it is significantly better here than it originally was.
After talking to my doctor again at my follow up, he told me that he feared that I would have some permanent cornea damage, but as it sits, I am expected to make a full recovery.
It is important to remember, when working with milkweed, or any botanicals for that matter, handle them with care and caution. Always wash your hands after handling them, and be cautious of wiping your eyes, lashes, or brow. Please do not follow my example, it is not an incident I would wish for anyone to experience.
You only have one set of eyes, so treat them with care, especially when working with milkweed. Our eyes are so very important, and in order to be able to view our beautiful garden visitors, they must be in their best functioning order.”