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Crazy Friday Science: New “Dua’s Layer” Discovered in Human Eyes, Ophthalmology Changed Forever

From May 28, 2013 onward, the study of the human eye will forever be changed.  A doctor named Harminder S. Dua, Professor of Ophthalmology and Visual Sciences at the University of Nottingham has discovered a new layer of cells that lies just above Descemet’s Layer of the cornea and the corneal stroma.  Like so:

duas-layer

“Now hold on there cowboy, what’s the cornea?!”

The cornea is the covering for the iris, pupil, and the anterior chamber  – basically the spot in front of the eye’s lens.  It’s one of the body’s most nerve-filled tissues, and it’s filled with fluid for light transmission.  Check this out, it’s an excellent visual description of the cornea, anterior and vitreous chambers — for reference, Dua’s Layer is right between the rear edge of the cornea (closest to the iris) and the middle of the cornea:

Three_Main_Layers_of_the_Eye

 

What Dr. Dua has discovered is a layer within the cornea that seems to have something to do with failures in the cornea where misshaping takes place.  These kinds of diseases are thought to be caused by water becoming waterlogged within the cornea itself, perhaps caused by a tear in this new Dua’s Layer.  They give the person afflicted a cone-shaped cornea that can be corrected with glasses, contacts, or in extreme cases, corneal surgery.  I’ve never seen anything quite like this before, so I’m guessing you haven’t either:

Keratoconus_eye

keratoconus-eye

from http://thesclerallenscenter.com/wp-content/uploads/2010/10/IMG_8964.jpg

Dua’s Layer is the new tissue discovery that is thought to cause things like this crazy degenerative keratoconus, which looks very annoying and painful to me.  Keratoconus causes pretty awful headaches and eye strain for people afflicted, which nobody wants.  But, this discovery is being heralded as a potential game changer for corneal diseases and degenerative conditions.  From Sci News:

“This is a major discovery that will mean that ophthalmology textbooks will literally need to be re-written. Having identified this new and distinct layer deep in the tissue of the cornea, we can now exploit its presence to make operations much safer and simpler for patients,” said Dr Harminder Dua, Professor of Ophthalmology and Visual Sciences at the University of Nottingham and lead author of a paper published in the journal Ophthalmology.

“From a clinical perspective, there are many diseases that affect the back of the cornea which clinicians across the world are already beginning to relate to the presence, absence or tear in this layer.”

The human cornea is the clear protective lens on the front of the eye through which light enters the eye. Scientists previously believed the cornea to be comprised of five layers, from front to back, the corneal epithelium, Bowman’s layer, the corneal stroma, Descemet’s membrane and the corneal endothelium.

…and from Science Daily:

The scientists proved the existence of the layer by simulating human corneal transplants and grafts on eyes donated for research purposes to eye banks located in Bristol and Manchester.

During this surgery, tiny bubbles of air were injected into the cornea to gently separate the different layers. The scientists then subjected the separated layers to electron microscopy, allowing them to study them at many thousand times their actual size.

Understanding the properties and location of the new Dua’s layer could help surgeons to better identify where in the cornea these bubbles are occurring and take appropriate measures during the operation. If they are able to inject a bubble next to the Dua’s layer, its strength means that it is less prone to tearing, meaning a better outcome for the patient.

The discovery will have an impact on advancing understanding of a number of diseases of the cornea, including acute hydrops, Descematocele and pre-Descemet’s dystrophies.

The scientists now believe that corneal hydrops, a bulging of the cornea caused by fluid build up that occurs in patients with keratoconus (conical deformity of the cornea), is caused by a tear in the Dua layer, through which water from inside the eye rushes in and causes waterlogging.

This is the first time I am ever researching Keratoconus — I have a good friend who has Retinitis Pigmentosa, another degenerative disease of the eye (in that case the retina), but the conical cornea is quite an odd phenomena.  Have you ever had or know anyone who has had this disease?  I found some information at WebMD on Keratoconus on diagnosis and treatment:

Keratoconus changes vision in two ways:

  • As the cornea changes from a ball shape to a cone shape, the smooth surface becomes slightly wavy. This is called irregular astigmatism.
  • As the front of the cornea expands, vision becomes more nearsighted. That is, only nearby objects can be seen clearly. Anything too far away will look like a blur.

An eye doctor may notice symptoms during an eye exam. You may also mention symptoms that could be caused by keratoconus. These include:

  • Sudden change of vision in just one eye
  • Double vision when looking with just one eye
  • Objects both near and far looking distorted
  • Bright lights looking like they have halos around them
  • Lights streaking
  • Seeing triple ghost images

To be sure you have keratoconus, your doctor needs to measure the curvature of the. cornea. There are several different ways this can be done.

One instrument, called a keratometer, shines a pattern of light onto the cornea. The shape of the reflection tells the doctor how the eye is curved. There are also computerized instruments that make three-dimensional “maps” of the cornea.

How Is Keratoconus Treated?
Treatment usually starts with new eyeglasses. If eyeglasses don’t provide adequate vision, then contact lenses may be recommended.  With mild cases, new eyeglasses can usually make vision clear again. Eventually, though, it will probably be necessary to use contact lenses or seek other treatments to strengthen the cornea and improve vision.

A last resort is a cornea transplant.  This involves removing the center of the cornea and replacing it with a donor cornea that is stitched into place.

Congratulations to Dr. Harminder Dua and his team at the University of Nottingham for this amazing discovery!
Keep up the excellent game-changing work, good sir!

dr-harminder-dua

Check out the abstract at the journal Ophthalmology.

keratoconus-normal

from http://www.centralohioeyecare.com/user-files/PageImage206991.jpg

Thanks to Wikipedia on Keratoconus, Dua’s Layer, Traffic Shaper!

Crazy Friday Science: Mini-Interview with Sonja Franke-Arnold on Rotary Photon Drag

I wrote an article about a paper I read in the journal Science a few weeks ago – the article was about Rotary Photon Drag Enhanced by A Slow Light Medium.  I got two handfuls of emails about the article, so I got in contact with one of the original paper’s editors, Sonja Franke-Arnold.  When you have questions, it’s best to go to the source!

JimOnLight.com:  Hi Sonja, welcome to JimOnLight.com! I’m very interested in your research, and we’ve gotten a lot of interesting response to the post I wrote on your paper, “Rotary Photon Drag Enhanced by a Slow-Light Medium.”  Can you take a moment and give us a bare-bones layperson’s look at what you and your team has discovered? What exactly has happened here in your experiment?

Sonja Franke-Arnold:  We were wondering how the world looks like through a spinning window!  About 200 years ago Augustin-Jean Fresnel predicted that light can be dragged if it travels through a moving medium. If you were to spin a window faster and faster, the image would actually be slightly rotated as the light is dragged along with the window. However, this effect is normally only some millionth of a degree and imperceptible to the eye.

We managed to increase the image rotation by a factor of about a million to an easily noticeable rotation of up to 5 degrees. This happened by slowing the light down to roughly the speed of sound during its passage through the “window” (in fact a ruby crystal). The light therefore spent a longer time in the ruby rod and could be dragged far enough to result in an observable image rotation.

JimOnLight.com:  Can you explain the significance of the wavelength of light you used? Why was 532nm (green) used for the experiment?

Sonja Franke-Arnold:  This wavelength excites a transition within the ruby crystal (the same that is also used in ruby lasers). Light at 532nm is absorbed and excites an atomic level with a very long (20 millisecond) lifetime. This allows to “store” the energy of the photon as an internal excitation of the rotating ruby crystal – generating slow light.

JimOnLight.com:  Tell me about the significance of the shape of the coherent beam in the experiment – was the shaped beam simply to observe a change in the image, or was a different purpose considered?

Sonja Franke-Arnold:  We used an elliptical light beam for two reasons, one of these is to define the image rotation angle as you suggested. The elliptical beam travelling through the spinning ruby rod however also plays an important part in making the slow light itself: At any particular position of the ruby, the elliptical light – spinning with respect to the ruby – looks like an intensity modulation. The varying intensity produces a large refractive index of about one million which slows the light down from the speed of light to roughly the speed of sound – a method pioneered by our co-worker Robert Boyd.

JimOnLight.com:  Could you give a few examples of uses for this discovery? How can the general populous relate to what this discovery really means for light and photonics?

Sonja Franke-Arnold:  For me, the main highlight was that we managed to observe a 200 year old puzzle – that images are indeed dragged along with rotating windows. We are now working on possible applications in quantum information processing: our image rotation preserves not only the intensity but also the phase of the light and could therefore be used to store and rotate quantum images. Access to the angle of an image could allow a new form of image coding protocol.

Thanks so much, Sonja!  Very cool paper for those of us nerds out here!

Crazy Friday Science: Man Hit in Skull During Robbery, Now He Can Draw Fractals by Hand

I always thought that ray diagrams from old books about optics and reflectors were so fractally beautiful, which is why this post relates for me.  What I mean is below, from an old text that I still use to explain reflectors:

This is a story about a guy who had to overcome some pretty stupid and mean business to discover that his brain was able to recreate fractals that were mathematically accurate – when he draws them by hand.

Yeah.

Meet the work of Mr. Jason Padgett, a mathematical savant.  It’s just three minutes, you have the time.  Sorry it’s a Fox News clip, at least it’s a local station:

This guy took a blow to the back of the skull which damaged his brain.  This damage caused the brain to compensate in such a way that gave Jason Padgett the ability to literally “see” math.  I mean, neurons are essentially firing light anyway, now Jason’s mind can interpret the synesthesia he’s experiencing.  That’s like being able to instantly and accurately interpret dreams.  How amazing is that?!  Someone grab this guy and start having him revolutionize battery storage and solar generation efficiency!

Check out some of Jason’s work, all obviously copyright Jason Padgett.  This stuff is gonna blow your mind – at least that’s my hope for this Crazy Friday Science post!

This first image is awesome – it’s Jason’s representation of a double-slit refraction test:

 

You need to go see more of these at the original post at NeuroBonkers, and then you need to go over and check out even more of Jason’s work at Jason’s art site.