July 2014

Hello and welcome to the eye research blog! I will give you a monthly update on the latest Ophthalmology research articles which I feel any medical professional interested in Ophthalmology will find useful and interesting. Enjoy!

Elewys Hearne

1. Early Age related Macular Degeneration can be seen in 35 – 44 year olds

In order to identify the age and gender specific incidence of Age related Macular Degeneration (AMD), the research team of the Department of Ophthalmology at the Mainz University Medical Center assessed the status of the ocular fundus of 4,340 participants in the Gutenberg Health Study. Vascular structure was assessed along with the head of the optic nerve, and the macula. The results unsurprisingly found that the incidence of AMD increases with age. The researchers also discovered that participants under the age of 50 years can already show signs of early stage AMD. In the age group of 35 - 44 year olds, 3.8 percent of the subjects were found to be suffering from the disease. These findings thus contradict the current assumption that age-related macular degeneration only occurs in the section of the population that is over 50 years old.

With the help of their findings, the researchers were also able to gain insights into how frequently the various forms of age-related macular degeneration occur. On average, about 12 percent of the examined 35 – 74 year olds had early stage AMD, but only 0.2 percent of the study participants exhibited symptoms of late stage AMD, which is often associated with severe visual impairment.

This research shows that age-related macular degeneration can occur much earlier than previously thought. This means there may also be possible consequences with regard to the screening examinations for these diseases.

References:

Korb CAKottler UBWolfram CHoehn RSchulz AZwiener IWild PSPfeiffer NMirshahi A. Prevalence of age-related macular degeneration in a large European cohort: Results from the population-based Gutenberg Health Study. Graefes Arch Clin Exp Ophthalmol. 2014 Feb 25. [Epub ahead of print]

http://www.uni-mainz.de/presse/17502_ENG_HTML.php accessed 30 July 2014

2. Human corneal tissue grown in mice using adult-derived human stem cells

Limbal stem cells replenish corneal cells as they become damaged. Injury or disease can lead to loss of these stem cells, and the eye loses its ability to keep the cornea transparent, resulting in significant loss of vision and eventually, blindness.

The only treatment option for patients who have lost their limbal stem cells is transplantation. This is complicated by the fact limbal stem cells are not easy to identify, so Ophthalmologists cannot be sure if the grafts are rich or poor in the essential stem cells.

In this study, Dr. Bruce Ksander, associate Professor of Ophthalmology at Harvard Medical School, and also of Massachusetts Eye & Ear Infirmary, and colleagues found that the gene ABCB5 acts as a marker for hard-to-find limbal stem cells, and is also essential for maintaining the stem cells and growing and repairing the cornea. They found mice lacking a functional ABCB5 gene lost their limbal stem cells, and their corneas healed poorly after injury.

Interestingly, mice deficient in limbal stem cells developed fully functioning, restored corneas, that were kept clear and normal, after receiving transplants of human ABCB5-positive limbal stem cells. In contrast, control mice that received either no limbal stem cells, or received ABCB5-negative limbal stem cells, failed to restore their corneas.

The researchers used antibodies to detect ABCB5 and confirm that tissue from deceased human donors contained limbal stem cells before transplanting them into the mice. They state ABCB5 keeps the stem cells alive, and protects them from programmed cell death or apoptosis. This study in mice is thought to be the first to show how the gene ABCB5 behaves in normal development.

References:

ABCB5 is a limbal stem cell gene required for corneal development and repair, Bruce R. Ksander, et al.,Nature, DOI: 10.1038/nature13426, published online 2 July 2014.

 

Massachusetts Eye and Ear news release accessed 30 July 2014.

 

EuroStemCell factsheet accessed 30 July 2014

 

http://www.medicalnewstoday.com/articles/279242.php accessed 30 July 2014

3. Noninvasive retinal imaging device may provide highly predictive early detection of changes associated with Alzheimer's disease

A noninvasive optical imaging device developed at Cedars-Sinai can provide early detection of changes that later occur in the brain and are a classic sign of Alzheimer's disease, according to preliminary results from investigators conducting a clinical trial in Australia.

Preliminary results showed the test could differentiate between Alzheimer's disease and non-Alzheimer's disease with 100 percent sensitivity and 80.6 percent specificity in a sample of 40 patients. The optical imaging exam appears to detect changes that occur 15-20 years before clinical diagnosis. It's a practical exam that could allow testing of new therapies at an earlier stage, increasing the possibility of altering the course of Alzheimer's disease.

The accumulation of beta-amyloid plaque in the brain is a hallmark sign of Alzheimer's, but current tests detect changes only after the disease has advanced to late stages. As treatment options improve, early detection will be critical, but existing diagnostic methods are inconvenient, costly and impractical for routine screening.

Positron emission tomography (PET) scans require the use of radioactive tracers, and cerebrospinal fluid analysis requires that patients undergo invasive and often painful lumbar punctures, but neither approach is quite feasible, especially for patients in the earlier stages of disease. PET scans are the current diagnostic standard.

The beta-amyloid plaques associated with Alzheimer's disease occur not only in the brain but also in the retina. By staining the plaques with curcumin, a component of the common spice turmeric, the researchers could detect it in the retina even before it began to accumulate in the brain. The device developed enabled them to look at the retina and see these changes.

This clinical trial was designed to enable researchers to correlate retinal plaque detected by optical imaging with brain plaque detected by PET scans. Studies involved patients diagnosed with Alzheimer's, a group with mild cognitive impairment and a group of people with no evidence of brain abnormality.

The retinal beta-amyloid plaque findings and optical imaging technology began with studies in live rodents and the post-mortem investigation of human retinas of people who had died with Alzheimer's.

This large double-blind clinical trial appears to validate this novel human retinal amyloid imaging approach using curcumin labeling. It further demonstrates significant correlation with brain amyloid burden, thereby predicting accumulation of plaques in the brain through the retina.

References:

Alzheimer's Association International Conference 2014, oral presentation: "Retinal amyloid fluorescence imaging predicts cerebral amyloid burden and Alzheimer's disease." (Copenhagen, Denmark)

http://www.medicalnewstoday.com/releases/279566.php accessed 30 July 2014

4. Spectral Edge plans enhanced video trial with Colour Blind Awareness

The technology company Spectral Edge has announced that it is working together with Colour Blind Awareness, an organisation that raises the awareness of the needs of the colour blind, to trial its new image-enhancement technology, EyeTeq.

EyeTeq uses mathematical perception models to modify image colours so that colour blind observers enjoy improved visibility, whilst at the same time minimising the strength of the effect for those who do not have colour blindness, or "colour normals".

Following a successful psychophysical study on a representative sample, EyeTeq is now being brought into living rooms and applying it to mainstream TV content. The technology company will gather direct feedback on the experience for colour blind viewers as well as colour normals. They hope the results will eventually cause consumer electronics companies delivering devices that are more colour blind friendly.

Colour blindness affects approximately 1 in 12 men (8%) and 1 in 200 women around the world. In the UK there are approximately 2.7 million colour blind people (about 4.5% of the entire population).

Applicable to both still pictures and video, Eyeteq enhances images so that colour blind observers can see details they previously could not, transforming the experience of watching TV in particular. It does this without negatively affecting the picture for colour normals, enabling both to share the same screen.

References:

http://www.realwire.com/releases/Spectral-Edge-plans-Enhanced-Video-Trial-with-Colour-Blind-Awareness accessed 28th July 2014

 

July certainly brought some exciting research. If you have any comments I would love to hear from you, my email is This email address is being protected from spambots. You need JavaScript enabled to view it.