Retinal Imaging Flashcards
Why is imaging eyes interesting?
Can tell you more about the brain through the eyes. The eye shares tissue and a blood supply with the brain. The retina is easily accessible to see using machines. These can also see in greater detail than MRI’s and PET scans.
What does the fundus camera do?
Take shot of the back of your eye. Beam from the annular source passes through the illumination system and the edge of the pupil back to the fundus. Light reflections are collected by an imaging system, the angle the light hits the eye has to be carefully checked.
What are signs of diseases you can see with the fundus?
microaneurysms, blurred optic disc, blood vessels, cotton wool spots, hardexudusand retinal hemorrhages. Lots of these are signs of diabetic retinopathy or issues with the vascular system in the eyes.
What can you look at with the funduc camera?
vessel widths, tortuosity, global complexity.
What does neurovascular pathology result in?
blood tissue barrier breakdown and blood flow dysregulation – this creates an environment with limited access to nutrients and oxygenation, inefficient clearance and neuronal death.
Why would you look at the retina of people with diabetes?
Diabetic retinopathy
Also these people are more likely to getalzheimersso they wanted to see if there is changes in the retina between these people and those who don’t have dementia. They found there was a difference in the nutrients and getting rid of waste through the blood vessels of the eye between dementia andalzheimers.
What is optical coherance tomography?
This is similar to ultrasounds but instead uses red light instead of sound. They record a spectrum of light from a sample – helps determine depth as you know how far and how long something takes. You can look at the different cell types and layers at the back of the eye.
What does optical coherance tomography show you?
Thinning, enlarging or inflammation is something to look for when looking for disease at the back of the eye.
They can create thickness maps from the layers seen in the eye, and compare to healthy volunteer cohorts or against themselves in the future.
You can also look at blood vessels using this technique and monitor them for any changes during disease.
What did they find when looking at the retina of people with MS?
They found that people with worse MS had more thinning of the nerve tissue on the retina which could be used as a non-invasive biomarker.
What is ultra-wide fundus imaging and what can you look at?
Lasers scan across the back of the eye using mirrors. You can get larger but less diluted images. You can look at arteries and veins and compare healthy people and those with dementia.
What is a OCT angiography?
This looks at a really small area of the retina and the small blood vessels. It uses lasers to catch scattered light which can tell you about the movement of blood through the eyes
What biomarker could OCT angiography be used for in the future?
Alzheimers
What is the Quantifying optic disc pallor study?
This is a study to see if thecolourof the optic nerve head is changing based on what is happening behind it.
What are challenges of quantifying optic disc pallor?
Artifacts, patient cooperation and image interpretation
Not all machines are created equal
A lack ofstandardisation
Pushing the technology to the current limits – resolution
A need for testing repeatability and reproducibility.
What are future trends of optical imaging?
Hand held and better resolution, also helping with translating these results in high street stores.
