1 00:00:02,040 --> 00:00:07,080 Speaker 1: Welcome to brain Stuff from How Stuff Works a brain 2 00:00:07,120 --> 00:00:12,240 Speaker 1: Stuff Christian Sager Here, Today's question is what our eyeboggers. 3 00:00:12,560 --> 00:00:14,440 Speaker 1: If you've ever had to wipe gunk out of the 4 00:00:14,480 --> 00:00:17,599 Speaker 1: corner of your eyes, it's not because you were visited 5 00:00:17,640 --> 00:00:21,360 Speaker 1: by the Sandman or a magical mucus ferry. Nope, we 6 00:00:21,560 --> 00:00:24,800 Speaker 1: live in a cruelly mundane universe, and I'm sorry if 7 00:00:24,840 --> 00:00:27,080 Speaker 1: I'm the first to break it to you, But eye 8 00:00:27,160 --> 00:00:31,080 Speaker 1: buggers are a build up of the pre corneal or 9 00:00:31,320 --> 00:00:35,120 Speaker 1: basil tier film that coats and protects your eyes plus 10 00:00:35,320 --> 00:00:38,919 Speaker 1: any foreign particles it catches. This tier film is just 11 00:00:39,159 --> 00:00:42,840 Speaker 1: three micrometers thick, which is less than half the diameter 12 00:00:42,920 --> 00:00:46,000 Speaker 1: of a red blood cell. But it's made up of 13 00:00:46,159 --> 00:00:50,760 Speaker 1: three components, the mucin, the aqueous, and the lipid. These 14 00:00:50,800 --> 00:00:55,760 Speaker 1: are indistinct layers of stuff that your body produces. The 15 00:00:55,840 --> 00:00:59,680 Speaker 1: aqueous component is the operative one. It nourishes, lubricates, and 16 00:00:59,720 --> 00:01:04,240 Speaker 1: fluff shows your eyes cells. It also smooths over microscopic 17 00:01:04,400 --> 00:01:07,600 Speaker 1: lumps and bumps on the surface of your eyes, creating 18 00:01:07,600 --> 00:01:12,440 Speaker 1: a smooth lens that optimizes light transfer into your retina. 19 00:01:12,640 --> 00:01:15,280 Speaker 1: The other two components are a support system for the 20 00:01:15,319 --> 00:01:18,720 Speaker 1: aqueous one. The musing component underneath it allows it to 21 00:01:18,760 --> 00:01:21,880 Speaker 1: temporarily stick to your eye, and the lipid component outside 22 00:01:21,880 --> 00:01:24,440 Speaker 1: it holds it in place so that you're not just 23 00:01:24,680 --> 00:01:29,399 Speaker 1: you know, crying constantly. So closest to your corneal surface cells, 24 00:01:29,440 --> 00:01:32,720 Speaker 1: you've got the musing component of the tear film. Mucins 25 00:01:32,760 --> 00:01:37,000 Speaker 1: are the proteins that make mucus slimy. They're important in 26 00:01:37,080 --> 00:01:41,720 Speaker 1: your eyes because corneal cells. Your corneal cells need water 27 00:01:42,120 --> 00:01:48,240 Speaker 1: and water soluble nutrients, but your corneal cells, unhelpfully are hydrophobic, 28 00:01:48,480 --> 00:01:54,080 Speaker 1: meaning they repel water like microscopic little ducks. Mucin helps 29 00:01:54,120 --> 00:01:58,200 Speaker 1: out by latching onto your corneal cells, specifically via adhesive 30 00:01:58,280 --> 00:02:03,600 Speaker 1: molecules called ico calyx that grow on the cell's surface, 31 00:02:03,920 --> 00:02:09,480 Speaker 1: and musants are hydrophilic, meaning that they grab onto water molecules. 32 00:02:10,120 --> 00:02:13,160 Speaker 1: Next up the aqueous component. As you may have guessed 33 00:02:13,200 --> 00:02:15,360 Speaker 1: from the name, this layer is made up of about 34 00:02:16,400 --> 00:02:20,919 Speaker 1: water plus two percent water soluble stuff. At any given time. 35 00:02:21,040 --> 00:02:24,360 Speaker 1: Part of that two percent is things your corneal cells need, 36 00:02:24,480 --> 00:02:29,639 Speaker 1: like electrolytes, oxygen, and antibacterial enzymes, and part is the 37 00:02:29,720 --> 00:02:33,680 Speaker 1: cell's waste. There are also some musans floating around in there, 38 00:02:33,720 --> 00:02:39,359 Speaker 1: and usually some dust debris, and you know sun dream microbes. Finally, 39 00:02:39,480 --> 00:02:41,959 Speaker 1: topping it all off, you've got the lipid component, a 40 00:02:42,120 --> 00:02:45,480 Speaker 1: k a. The me bum. It's made mostly of wax 41 00:02:45,520 --> 00:02:50,080 Speaker 1: and cholesterol esters. These esters are slick, hydrophobic substances that 42 00:02:50,120 --> 00:02:54,480 Speaker 1: our bodies used to lubricate and waterproof various tissues in 43 00:02:54,520 --> 00:02:57,520 Speaker 1: the tier film. They float on top of the aqueous layer, 44 00:02:57,600 --> 00:03:01,400 Speaker 1: helping our eyelids glide easily over our eyes. They also 45 00:03:01,480 --> 00:03:05,440 Speaker 1: provide a strong surface tension for our basil tears. Without 46 00:03:05,480 --> 00:03:08,840 Speaker 1: the lipid layer, our tear film would drip right off 47 00:03:08,960 --> 00:03:13,440 Speaker 1: our eyeballs. But how do these components become eyeboggers and 48 00:03:13,560 --> 00:03:16,880 Speaker 1: why do they accumulate in the inner corners of your eyes. Well, 49 00:03:17,000 --> 00:03:19,800 Speaker 1: I'm going to tell you. When you blink, your entire 50 00:03:19,960 --> 00:03:25,520 Speaker 1: eyelid doesn't close simultaneously. It shuts like a clapboard from 51 00:03:25,520 --> 00:03:29,079 Speaker 1: the outer corners of your eyes inward towards your nose. 52 00:03:29,639 --> 00:03:33,720 Speaker 1: Your tear film gets pushed along by that motion. Upon 53 00:03:33,840 --> 00:03:36,840 Speaker 1: reaching the inner corner of your eye, most of the 54 00:03:36,880 --> 00:03:40,680 Speaker 1: film drains out through the tear ducts, which empty into 55 00:03:40,720 --> 00:03:43,680 Speaker 1: your nasal cavity. And some of the film. The musans 56 00:03:43,720 --> 00:03:47,160 Speaker 1: and oils and debris can clump together and get stuck. 57 00:03:47,560 --> 00:03:50,160 Speaker 1: When enough of that builds up, it forms the goop 58 00:03:50,320 --> 00:03:54,080 Speaker 1: known as eyeboggers, and when it accumulates and dries overnight 59 00:03:54,160 --> 00:03:57,400 Speaker 1: because you're not blinking it away, it forms the crusty 60 00:03:57,480 --> 00:04:05,920 Speaker 1: gunk known as sleep or saying. Check out the brainstff 61 00:04:05,960 --> 00:04:08,320 Speaker 1: channel on YouTube, and for more on this and thousands 62 00:04:08,320 --> 00:04:24,040 Speaker 1: of other topics, visit how stuff works dot com.