Eye Works 1: Focusing: Cornea, Iris and Lens
Вставка
- Опубліковано 16 лип 2011
- How the Eye works to focus an image. Cornea, Iris and Lens structure and function in detail. Iris color, Accommodation, Cataract. Photos and diagrams.
CBlackwell2011 - Наука та технологія
Dr. Blackwell, you have the kindest voice.
This is the best video that I have found on how the eye focuses. I am extremely grateful to Dr. Blackwell for providing it.
Yeah he's really good at presentation and explanations!
Just the right amount of information for the normal person. I also like your conversational voice. Thanks for posting.
I agree his voice is perfect isnt it :) So calming.
The best video I have seen on this subject for which I have to write an essay. It is really clearing things up for me thank you!
Thanks for the nice, clear video. I love the use of a beautiful painting for showing the mechanism of tearing.
My Opthalmic Tech job brought me here. The human eye is the most beautiful thing I have ever seen, magnified!
I agree, an awesomely complex and interesting structure. As a tech you will see a world of things you never expected.
This is great. I teach medical students and this really explains things well.
An excellent review!
wow. great video! incredibly informative, easy to follow and understand. thank you so much for sharing. this give's me a whole new understanding of what it is to be a living organism! what an amazing device. and a flexible lens that can change shape! and how we don't have to contract and relax our iris muscles, but that they function on their own according to how much light there is! incredible. absolutely incredible.
I found this video to be very instructional. I am having cataract surgery next week and this video explained alot. Thank you for the information and I found your voice to be very calming.
Thank you for this video. It was very well explained and is the only video I need. This is the most in-depth analysis I have seen so far, good work, keep it up
Well done, 🥰👌👌🖐👋🖐👋✌✌✌👍👍
Thank you for such clear explanations. This video has been extremely beneficial throughout my studies.
You must be a passionate doctor and teacher . Thank you for your wonderful video. I could use this video to explain how to protect their eyes to the kids in my daughter's class.
you literally just saved me. Amazing video
Great Video! Wonderfully clear explanation!
Hi Craig,
That is indeed my friend's father. I did not realize the book has been such and outstanding success!
Very instructive video. Many thanks!
. . . thanks for this one doc! was looking for an animation on the physiology of eye accomodation. you video is indeed a perfect complement with Guyton's explanation.
Gary, don't worry, it's not scary. Measurement is painless and takes only a few seconds with a hand held ultrasound device. Corneal thickness varies from person to person just like height. It provides an important correction factor to determine the true intraocular pressure. For more information look at my videos on Glaucoma.
Thanks. Guyton, one of the best books in med school. (Though my edition was an early one.)
Best video I have found in a long time. Thank you for this!
Appreciate Video! Apologies for the intrusion, I would appreciate your thoughts. Have you thought about - Ciyackorn Lothario Fraternity (erm, check it on google should be there)? It is a good one off product for finding the secret to improve your eyesight naturally without the hard work. Ive heard some pretty good things about it and my old buddy Taylor got astronomical success with it.
Good video thanks for posting! This definitely helped me in my anatomy class.
omg i was getting so confused on what specifically is th retinas job and this helps so much:)
im in love with the iris
Our eyes are fiber optic pictures of our brains
Great video. I am really glad that I found this!
Excellent video !
The iris looks like an amazingly superstructure with many fibrous elements in a network arrangement. With paler eye color, these iris elements appear white. Is this the color of the smooth muscle? It is unimaginable to have different colors of these smooth muscle in different colored eyes. So the smooth muscle should be all white with different pigments that end up differently colored eyes? Are the smooth muscles are single fibers or in thin fiber bundles like the skeletal muscle?
Take my like and my subscription, very informative video. :)
Craig, Your two introduction videos on how the eye works will be great for my AP Psychology classes. Thanks!
it's really nice well explained really liked it...!!
Thank you for your video sir it's so useful to understand the subject matter😎
Think about it this way. With your glasses on your focusing muscles are doing the same amount of work as someone who isn't near-sighted. With them off the muscles do a bit less work than someone who doesn't have the advantage of being near-sighted. But they are designed to do that work. No harm is expected. Lens damage comes from other things like UV exposure and diabetes.
Thanks, greay way to understand how vision works.
nice video. it really helped me in when i was doing surgery in Nigeria. Thanks a lot Craig Blackwell
I like they used Renaissance paintings as examples
This is a pleasant presentation.
Dr, a couple of questions, if i may. 62 year old male with a cataract in left eye. i can barely pass the CA DMV eye test from the counter, which i did in April 2016. my vision is cloudy, foggy in this eye.
what kind of IOL do you suggest? i am retired, don't do much vehicular driving and am not out much at night. what is a basic IOL called? any specific brand?
secondly, does all cataract surgery come with a new IOL?
Great videos. many thanks.
Thanks for the answer. My qustion was more geared towards how the eye reacts to focusing up close while wearing glasses(since I dont need them to see up close). You said this wont harm my eyes, but is it not true my eye will have to compensate someone for viewing up close with classes? If I wear glasses all the time could if actually cause my lens to degrade more quickly then it would normally?
Wow! Thank you Craig - bless your heart for making such an informative video! 5 Stars!
thank you for your video...awesome
Makes sense, thanks for the response.
An excellent exploration. Thank you for this most informative discussion. Billy Weprin
This video is great i can learn this video for my science subject.
Do you know why irises appear to have different structure? I have been looking at macro photos of eyes and they are fascinating.
Where good lecture.Thank you.
fantastic video
thanks, this helped a lot.
Question. Is it possible to focus one eye at a time? They are not mechanically linked. So it should be possible?
I dont know if anyone one on here would known but I really need to know something. I have distance problems and just got glasses. Im trying to figure out if looking up close actually stresses my lens(im young). Since I can see up close Im a bit confused how my lens adjusts of if it does extra work since my distance visor is now magnified.
Amazing how complex some so tiny as the eye is
But why don't we see the space around the object, I mean if light rays are bouncing off randomly from all parts of the object then these rays would coincide at several points in space around the object so why don't our eyes focus these mixed rays coming from different-different parts over the retina, making those points visible? How our eye lens treats light rays from different parts seperately?
TC, if your vision is blurred at distance, but clear up close, then you are likely to be 'near-sighted.' Your focusing muscles and Lens are designed to work together to change focus. WS was correct, except for the eye strain. If you are young you have a lot of reserve for close focus; no harm results whether you read with or without glasses. Your optometrist was explaining that the ability of the Lens to change shape decreases (linearly) with time. Unfortunately, not much you can do about it.
awesome vid
Is pupil is the part of or made from lens....??
i have got kerotoconus and im only 23. my cornea is basically like a vone instead of a dome. but i am having cxl to stp the condition
I have just been told that I have raised pressure in both eyes. I was told they will
propbably do tests to determine the thickness of the Cornea. What does this involve. I was born with Nystagmus and Astigmatism, and I am in my mid 50's.
I am a little apprehensive about what I might need to have done. I have had the
field vision test and had Tonometrey pressure test done twice, which gave a reading
of around 26, but I don't know what that means. He told me anything above 21 is
considered to be high. I passed the field vision test, for peripheral vision, but my
eye pressure is what he would call on the high side. Can anyone help?
high eye pressure means you are at the risk of glaucoma, please got treat it as fast as you can, because the vision lost by glaucoma , can not be backed by any means
Hi Doctor, why is it that no light can enter my eye after an eye accident, is it a problem with my cornea, lens, or could it be internal blood staining of the working parts of my eye.?
Hi Craig,
I was curious about the name of the book by Dr. Guyton. I have a friend by that name - and I think they are related!
Thanks!
loss sight over night as is all is now like a 40 watt sun now. My pupils was changed to square on one eye .
A diifernt size but both eyes did same of darkness over night.
I saw eye fella he nice person.
thanks alot , alot of thing became clearer
How do people have texture in the iris when taking photos? It doesnt look I have any at all. It looks like I just have black eyes and it does not look cool to me. I have asian in me and idk if it has something to do with or not.
This is an awesome video.. helped me with my test.
Thnx for posting this EPIC CHIZZ
So your saying that when I look up close with glasses this can cause strain to my eye? Im a young guy 23 and my optometrist just said you will be fine to see up close because your lens adjusts(over 40 and you may need bifocals). When I look up close with my glasses I can see just as clear as without them but it just confuses me how my eye can do this when the glasses magnify my vision in a sense.
If you're a fairly normal case, your eyes are able to focus normally, but your cornea is oddly shaped. Glasses undo this optical variation.
I'm assuming you're nearsighted, since you mention "Up Close". Your eyes do need to focus more for the same distance with your glasses on, since the glasses lens is directing focus farther out. This can easily cause eye strain.
I would recommend removing your glasses in cases where you need to inspect something closely.
Textbook of Medical Physiology by Arthur Guyton. Now in its 11th edition, authors Guyton and Hall. (Note: Unfortunately migraine explanation is out of date.)
study the eye study the soul
Thank you for the kind comment. Where do you teach?
i enjoyed this video though thanks doc :]
Thank you sir
Cool. You might also want to take a look at the color vision series, really interesting subject. A lot of visual physiology work is done in psychology departments.
Thank you for the kind comment. How is ophthalmology in Nigeria?
It's not like while it was saying about distance focusing I was pulling my iPod really close to my eye. On lowest light, of course.
Thanx
This helped me understand my lessons thanks for vid brah
Tq sir
Can you Sir ,make some videos on the basics of slit lamp exam ,please
I had not thought of that. Have a couple projects currently in the works. After that, interesting idea.
Sir I've visual acuity of 20/200😒
Wt shud I do
if this video is accurateThat means the problem with myopic patients is their focusing muscles do not relax well enough so the lens is always rounder not flatter
Let me expand that thought. The need for glasses means there is a mismatch between the strength of the focusing system and the length of the eye. "Near-sighted" (myopia), means that when the focusing muscles are relaxed, the image comes to a focus in front of the retina. "Far-sighted" (hyperopia) means the image comes to focus behind the retina.
So the only way to cure myopia is to increase the focusing power of the lens since you cant reduce the size of the eye
Craig Blackwell
Craig Blackwell hello sir my son problem not fous thing and corena problem doctor advise plz inform me which treatment strat plz
From what I've read, the problem with people who suffer from nearsightedness is that their muscles do not relax, so that could definitely be one of the contributing factors.
Cell
Can anyone imagine how would b our creator who created this small thing???
"That's the reason today scientists are not rejecting the GOD they are rejecting the MODELS OF GOD....
Alhamdulillah (Praise be to GOD)
k1wahippul
I think that doing surgery on your eyes are crazy. I watched a video the other day and it was fun yet disgusting to watch