I know this is from a few months ago, but I just saw it. The cornea–the clear “windowpane” covering the iris and pupil, does indeed have nerve endings. In fact, it has several hundred times as many nerve endings as the skin does. The conjunctiva, the part of the eyelid that touches your eye, also has nerve endings.
The cornea does not normally have blood vessels in it. Hypoxia, however, can cause nerve vessels to grow into the cornea.
The diameter of rigid contact lenses varies. While you’re correct that some rigid lenses are smaller in diameter than the iris, some, such as scleral lenses, are larger.
If anyone had actually fallen into a concrete pour they would have gone to great lengths to get the person out since it would have created a weakness in the dam.
Thanks for the information, very interesting. Does your quote mean that if I wear contact lenses and thus reduce the flow of oxygen my cornea gets from the air this cornea will grow more nerve endings? Might it then become more sensitive, for instance to contact lenses (or dryness, or dust, or whatever), making them less comfortable to wear?
This is a relatively* recent discovery that I read about in Smithsonian magazine 10-15 years ago. In the article, they said that after they discovered this, they doubled the known number of scorpion species in a year. And found them in areas that no one thought scorpions lived in.
The original “Big Tex”, the iconic giant who welcomes visitors to the Texas State Fair, began life in 1949 as a Santa Claus in Kerens TX. The huge Santa was sold to the State Fair in 1951 for $750,
He is very similar to Paul Bunyan statues that were all over the country. Many had a raised arm just like that and in other poses but the arm broke off of most of those over the years. Others were converted to other characters, some locales didn’t like the look of a giant carrying wielding an axe.
Oh, crud. That was a typing error. I should have said “Hypoxia can cause BLOOD vessels to grow into the cornea.” So sorry!
Contact lenses allow sufficient oxygen to permeate the lens and get to the cornea. They also allow tears to get between the lens and the cornea. In my own case, due to a corneal condition called keratoconus and many surgeries, some contact lenses stuck to my cornea like suction cups and didn’t allow enough oxygen to get to the cornea. As a result, I have blood vessels that grew into the outer rim of the cornea. This, however, is very rare.
The number of nerve endings doesn’t change, though it may feel like it if you get an eyelash caught under the contact lens!
I’m so sorry for the typo. I don’t know why I didn’t catch it before posting.
Don’t worry, thanks for the correction. I was wondering, as I have been wearing lenses for ages (since I was 12, and I am 55 now) and never did have any problems with them nor did I have the impression my eyes were getting more sensitive, that is why I asked. What you say makes perfect sense now, thanks again!
During Prohibition there was a neurologial disease called “jake leg” or “jake walk” caused by people drinking Jamaica Ginger Beer purposefully tainted with tricresyl phosphate to fool government tests. It was common enough that songs were written about it in the early 1930’s.
That’s not what I find interesting. Despite how widespread it was and a part of American culture, there doesn’t appear to be any film of the effects.
This year’s fly-in at Oshkosh WI in July was canceled. Wikipedia says:
By the way, Wittman Field was named for Steve Wittman (1904-1995), who raced and designed planes. His pilot’s certificate was signed by Orville Wright. He died when his plane crashed because a wing failed.
Speaking of aviation facts, the Breda-Zappata B.Z.308, the airliner seen in the movie Roman Holiday (that I watched today), was the only one of its kind. It was damaged beyond repair in Mogadishu a year after the film and broken up for scrap.
Another aviation fact. As a strange side effect of the drastic downturn in air travel due to the COVID pandemic, at least as of a couple of months ago there were more DC-8s actively flying than A380s.
We went to Lake Havasu City, and saw something about the London Bridge, and drove around looking for it, we crossed over it a couple times before we discovered that we had driven over it a couple times =)