#fundus

Vessel View

Atherosclerosis – the build-up of fatty deposits, or plaques, within blood vessels – can affect the arteries supplying the heart (coronary artery disease), brain (cerebrovascular disease), limbs (peripheral artery disease (PAD)), or a combination of the three. In the case of PAD, early stages can be symptomless and yet still increase the risk of heart attack and stroke. Timely diagnosis is thus highly desirable but difficult. The good news is, scientists have discovered changes to blood vessels in the retina associated with PAD – even in early-stage disease. While the changes are often subtle, by using thousands of photos of human retinas – the sort taken during routine eye exams – scientists have been able to train a machine-learning algorithm to distinguish healthy from unhealthy retinas. In a small-scale trial, the software detected PAD-related vessel alterations and correctly diagnosed 80 percent of patients, spurring hope for its development into a diagnostic screen.

Written by Ruth Williams

Image from work by Simon Mueller and Maximilian W. M. Wintergerst, and colleagues

Bonn-Aachen International Center for Information Technology (B-it), and Departments of Computer Science and Ophthalmology, University of Bonn, Bonn, Germany

Image copyright held by the original authors

Published in Scientific Reports, January 2022

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its a fantastic piece but we need your help to make it happen. If you can donate as little as £5 or $5 even £1 will be greatly appreciated

I will preface this with saying that I very much do not like eyes when they go bad. Traumatized eyes turn my stomach a bit. Not sure why, but they always have. It’s the one thing aside from cracking ribs in veterinary medicine that still bothers me.

I was fortunate to have several rotation-mates, which spread out the workload of this busy service. We saw any kind of species that wanted a referral, but were required to take both a large animal case (most common is horses) and a small animal case. I was really let off the hook by being told that I only had to take one horse case due to my allergies (which is the first time in my clinical rotations that has been considered). It was very sad that we did not see any exotics because the rotation before me had rabbits. Rabbits have a cool fundus (see below)! So, I borrowed some equipment to look at Coriander’s fundus which is even better because of his tyrosinase mutation.

Ophthalmology is a lot more subjective than many other specialties I have encountered because there are so many nuances and it’s all about what you can see.  I have gotten good at doing a basic ophthalmic exam and I still got to see a lot of every day problems. I know that I will not wait on eyes and I encourage people who see changes in their pet’s eyes to get the problem figured out early.

I learned how to enucleate (surgically remove) an eye relatively quickly. It is not my favorite surgery, but I can do it which is more than I could say before this rotation. As a side note, horses post-enucleation sink in and look like they should be thestrals, so they often opt to insert a prosthetic simply for cosmetic effect.

At this juncture, I have to add that non-bird species do extremely well as blind animals. So often owners want to pursue treatment to ‘save’ vision despite an extremely poor prognosis for return of vision and continued pain for their pet. Our companion species do not rely on sight as heavily as we do. A lot of the owners that came in were not even aware their pet was blind! I remember having a diabetic Golden growing up who we thought was seeing around his cataracts fine until we moved to a new home. They truly have great spatial orientation, remember where things are.

Did you know, that behind the wonder that is the surface of the eye, is another layer of anatomy ready to be explored? The back of the eye, or the fundus, consists of sclera, choroid, retina, the optic nerve, and plus or minus the tapetum. 

The fundus can be seen by several different methods, such as direct ophthalmoscopy or indirect ophthalmoscopy (as seen below).

images from vetbook.com

Seeing Trouble

Poetically described as the windows to the soul, our eyes can also reveal the condition of our hearts. Small changes in the fine blood vessels supplying the retina, the layer of light-sensitive cells in our eyes, are linked to characteristics of the heart associated with cardiovascular disease. These subtle signs can be revealed with retinal scans (pictured), a technique routinely performed by opticians to diagnose diseases of the eyes. Using machine learning techniques, researchers devised an artificial intelligence system capable of estimating heart properties and predicting the risk of heart attacks based on retinal scans: after training with over 5000 patient images, the system could identify patients likely to experience a heart attack with around 70% accuracy. With further refinements, this tool could mean that, in future, checking your vision will also flag up elevated risk of serious heart conditions, improving the chances of earlier detection and more effective treatments.

Written by Emmaunelle Briolat

Image from UK Biobank

Research by Andres Diaz-Pinto and colleagues, Centre for Computational Imaging and Simulation Technologies in Biomedicine, School of Computing, University of Leeds, Leeds, UK

Image copyright held by the UK Biobank

Research published in Nature Machine Intelligence, January 2022

Stomach Upset

Figuring out how vital organs like the stomach first develop is a struggle – it’s difficult to watch cells knitting together in the womb. One alternative is this stomach 'organoid', a living model grown from human stem cells. Early in life, our stomachs developed the fundus – an area which produces acids and enzymes required for digestion. Proteins called Wnt and β-catenin usually switch on or off inside early stomach cells to guide development – disrupting them in this fundus organoid reveals catastrophic effects (pictured). Shown with its cells artificially coloured, the organoid has very few green-coloured acid-producing cells, and the pink-red cells are developing more like tissue characteristic of a different part of the stomach. Using organoids to mimic different stomach regions, together with intestinal organoids, may allow scientists to recreate the early digestive system, and look for clues about a range of developmental disorders.

Written by John Ankers

Image courtesy of Professor James M. Wells, Cincinnati Children's Hospital Medical Center

Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA

Image copyright held by original authors

Research published in Nature, January 2017