The non-invasive method uses fluorescent markers, which enable early indication of brain cell death by attaching to dying cells on the retina. The dying cells absorb the fluorescent dye which show up as green dots. (Image Below)

These experiments are currently being tested on mice, but the first human trials could begin this year. This fundamental development has the potential to revolutionise diagnosis for Alzheimer’s disease.

Currently 700,000 people in the UK live with Alzheimer’s and other dementias. Alzheimer’s disease can only be positively diagnosed by a post-mortem, when microscopic changes caused by the disease are closely examined. Nevertheless doctors can diagnose through process of elimination and costly MRI scans which they refer to as probable Alzheimer’s disease.

The research could enable scientists to overcome the problems and complications of investigating what is happening inside the brain of those with Alzheimer’s disease. Being able to detect Alzheimer’s in its early stages with a simple eye test opens up new avenues for treatments with the possibility to reverse the progression as new drugs are developed.

Professor Francesca Coredeiro, lead author from University College London Institute of Ophthalmology said: "Few people realise that the retina is a direct, albeit thin, extension of the brain.

"It is entirely possible that in the future a visit to a high-street optician to check on your eyesight will also be a check on the state of your brain."

"I hope that screening for Alzheimer's will be available on the high street within five years."

By identifying and comparing retinal cell death over a period of time could support scientists in cataloguing the progression of the disease however much more research is required before any considerations can made to use this technique for the diagnosis of Alzheimer's disease.
 

Eating carrots to help see in the dark is not just an old wives’ tale – the Vitamin A present in carrots as carotenoids is vital to eye health. The powerful antioxidants known as lutein, zeaxanthin and lycopene in carotenoids protect healthy tissue against damage from free radicals which are produced by cell metabolism. Insufficient vitamin A leads to reduced night vision, susceptibility to infection and conjunctival corneal drying. Carotenoids are also found in other brightly coloured red and yellow fruit and vegetables and dark green leafy vegetables.

Another easily consumed supplement is the Vitamin B complex. Vitamin B2 (riboflavin) plays an important role in maintaining optic nerve health and is an antioxidant that may help ward off cataracts. It is found in many foods, especially Marmite which has 11 milligrams per 100g, the highest of any foods. Offal, wheat germ, milk, hard cheese and – believe it or not – faggots are also at the top of the list. Deficiency of Vitamin B in a normal diet is rare but absorption by the digestive system of B1 and B12 in particular is easily reduced by alcohol.

Vitamin E is the third musketeer in the store cupboard of eye health. Vitamin E is a generic term for a group of substances of which the most important is tocopherol. This is connected with the protection of cell membranes and helps protect vitamin A from oxidation in the retina. Vitamin E is present in many foods and deficiency in a normal diet is rare but may arise in people with digestive problems who are unable to absorb dietary fats. Lack of vitamin E causes neurological problems due to poor nerve conduction.

Store cupboard foods high in vitamin E include sunflower and vegetable oil, peanut butter, eggs and cereals containing wheat germ.

Trace elements are less understood than vitamins but it is believed that they are minerals required in small quantities to help vitamins to work. Selenium and zinc are important in the preservation of ocular health.

Selenium works with vitamin E to have an antioxidant effect. A lack of selenium is linked to the development of cataracts and age-related macula degeneration (AMD). Foods high in selenium include mushrooms, salmon, tuna and Brazil nuts.

Zinc is a critical trace element and is involved in antioxidant activity. It has a vital function in the metabolism of vitamin A and is found in the choroid and retinal receptors and may help to maintain the health of the crystalline lens. Zinc deficiency causes poor wound healing and night blindness and has been linked to disease of the optic nerve. Shellfish and red meat are high in zinc but for vegetarians eggs and dried fruit are the next best source.

Many studies have taken place on understanding the function of nutrition and dietary supplements and their effect on vision. Some show that dietary supplements can be beneficial while others show no benefit at all. Most experts agree that a healthy diet is by far the most valuable way to obtain nutrients from food but sensible use of supplements provides a good back up for those whose lifestyle and dislikes – such as Marmite – means they are missing out.

What’s next?

Do you protect your eyes from the harmful UV radiation of our sun? Most of us cover up our skin to protect ourselves from sunburn but what about your eyes? Tomorrow we will visit the dangers of ultraviolet radiation to our eyes, see you then…

This week we have 7 articles to share with you relating to the health of your eyes, please share these articles with your friends and family to promote Eye Health Awareness week 2010, together we can make a difference to encourage regular eye examinations.

What is the Macula?

The Macula is a very small part of the retina that converts the light entering the eye into an image. This delicate tissue is situated at the very center of the retina and is accountable for our central vision enabling us to undertake activities such as reading and writing, the macula is also responsible for our ability to see in colour.

What is Macula Degeneration?

The delicate cells of the macula may progressively deteriorate over time and eventually stop working altogether. This is sometimes called age related macula degeneration or may also be known as AMD. The condition is found largely in elderly patients and sometimes in middle aged ones too.

There are two forms of AMD, usually referred to as ‘Wet’ and ‘Dry’. In general dry macula degeneration is the most common of the two.

Dry AMD will gradually deteriorate over a period of a few years; many people notice a gradual central blurring with the peripheral vision unaffected. The colour can also fade similar to an old photograph. For most patients with AMD there is currently no effective medical treatment however low vision aids such as magnifiers can provide some help with reading and close work.

Wet AMD is another less common form distinguishable by the formation of new blood vessels growing behind the retina that causes bleeding and scarring resulting in total loss of central vision. If detected early laser treatment can prevent further deterioration of visual acuity. Broadly speaking Wet AMD accounts for about 10% of all AMD cases.

The image below shows the same scene as viewed with normal vision, and then with age-related macula degeneration.

Causes of Macula Degeneration

The cause is believed to be the loss of function in the retinal pigment epithelial cells of the retina although the exact cause for AMD is unknown. There are differing risk factors linked with macula degeneration indentified below:

Age – As the name suggests age related macular degeneration tends to occur in elderly patients.

Sunlight – Studies have also shown that macula degeneration has a significant link with UV exposure even though only a small amount of UV actually reaches the retina.

Nutrition – Studies have shown that a varied and balanced diet can supply us with all the vitamins and trace elements needed to protect us against AMD. Omega 3 found in oily fish can also help, click here for the BBC news report.

Smoking – Smoking has been linked to the development of AMD in various studies. It is also evident that to quit smoking can significantly reduce the risk of developing AMD.

Gender – Macula degeneration tends to be slightly more common in women than men.

Genetics – Research suggests the likelihood of developing AMD can be linked to a number of genes passed through families.

Conclusion

There is a clear message here, and that is to ensure your optometrists closely monitor the health of your eyes by attending regular eye examinations. It is important to understand that a sight test is not simply to check if your prescription has changed since your last eye test but to confirm the general health of your eyes.

What’s next?

Tomorrow’s article is on the importance of regular eye examinations.

Some people can lose up to 40% of their vision before they are even aware there is a problem, so if you thought your vision was good just because you can still read the article, think again! Regular eye examinations are not simply to obtain a new prescription and new glasses, they are essential for the general health of your eyes and vital for controlling serious visual loss from glaucoma and other ocular conditions, early detection and treatment are key for the prevention or slow down of further damage by glaucoma.

The disease has no symptoms, pressure within the eye slowly rises which can damage the eye’s optic nerve, additionally a weakness in the optic nerve may also cause damage both resulting in a loss of vision peripherally and if left undiagnosed can result in blindness. The optic nerve is a motor nerve that connects the light sensitive layer of the retina with the brain. This nerve penetrates from the rear of the eye sending all information from the retina to the brain where it is perceived as a picture. See Figure 1 below.

Figure 1. The Eye

How Pressure is controlled in the eye

A watery fluid called Aqueous is produced by cells behind the iris that we see as the coloured part of the eye. Figure 2 illustrates how Aqueous flows between the iris and the lens through the pupil and into the anterior chamber, where every minute, about 1% of its volume is removed from the eye via tiny drainage channels known as the trabecular meshwork and into the canal of schlemm to be removed into the blood stream. If this Aqueous fluid does not drain due to a blockage or too much is produced faster than it can escape then the pressure in the eye will rise. It is important to note that the aqueous fluid is not related or connected to tear production.

Figure 2. Flow of Aqueous fluid

Increased Intraocular Pressure

The optic nerve is sensitive to pressure; too much pressure will cause varying damage subject to how much pressure there is and the duration it is exposed to this pressure. Other factors such as the blood supply and any weaknesses in the optic nerve can also contribute to this damage. The normal intraocular pressure (IOP) within the eye has an average value of 15 to 16mm Hg.. Glaucoma is characterized by an IOP over 21mm Hg., high pressure will damage the optic nerve promptly. A lower level of pressure can cause damage progressively over a longer period of time where sight would gradually be lost if not treated.

Although Glaucoma cannot be prevented or cured, early detection and treatment through regular eye checks ups which are typically at least every 2 years are essential in controlling serious visual loss from Glaucoma, treatments such as drugs and surgical procedures have improved considerably over recent years saving the sight of approximately 95% of those diagnosed early. Despite the fact that anyone can potentially develop glaucoma there are some people that are considered to be at a higher risk, these include:

• Family Members with Glaucoma
• African-Caribbean origin
• People over 40 years of age
• People with Diabetes
• High Myopia (Short-sighted)
• Hypertension
• Hispanics in Older age groups
• Asian origin
• Steroid Users
• Eye Injury

Types of Glaucoma

Glaucoma can be sub-divided into four main types:

Open angle Glaucoma

This is considered as the most common of the four, sometimes referred to as Chronic Glaucoma, chronic meaning a slow progressive condition. This type of Glaucoma affects at least one person in 200 over 40 years of age; regular eye check ups are essential to monitor the health of your eyes if diagnosed with open angle glaucoma.

The pressure within the eye rises very slowly over many years due to a blockage in the drainage channels known as the trabecular meshwork and canal of schlemm; this is where the aqueous fluid returns to the blood stream. Figure 3 illustrates Open angle glaucoma below.

Figure 3. Open Angle Glaucoma

The raised pressure is transmitted to the optic nerve damaging the retinal nerve fibers and reducing their blood supply resulting in a gradual peripheral visual field loss but with no pronounced pain or changes to your prescription. The loss of vision is usually in an arc shape, shown below in grey, figure 4 as arcuate scotoma following the course of the retinal nerve fibers, which can spread inwards and outwards, central vision is typically affected last causing a tunnel vision effect.

Figure 4. Fields

There are three tests that should be undertaken which are effective in detecting glaucoma, these tests are:

• Viewing your optic nerve by using a special instrument called an Ophthalmoscope
• Measurement of the internal pressure of the eye using various techniques which can be discussed with your optician
• A visual field test – small spots of light are randomly shown on a screen for you to confirm which can be seen.

Those most at risk of open angle glaucoma are short sighted (High Myopia), Afro-Caribbean origin, people with Diabetes or high blood pressure.

Treatment

A referral to the consultant at the hospital will be made by your optician with the aim to reduce the pressure in your eyes; typically this treatment simply involves eye drops. These eye drops will be responsible for opening the drainage channels so that excess aqueous fluid can drain away appropriately or by limiting the production of aqueous fluid. Surgery may be necessary if the eye drops are not successful. Your consultant may suggest laser treatment or an operation known as Trabeculectomy depending upon your particular case.

Closed angle Glaucoma

Closed angle glaucoma is more common among people of Chinese origin and less apparent in western countries affecting one person in 1000 over 40 years of age, this is sometimes referred to as Acute Glaucoma. Symptoms include blurred vision, coloured haloes around lights, and a red, painful eye or eyes, which could be sever enough to cause nausea and vomiting. Closed angle glaucoma is brought about by a rapid increase in pressure caused by a shallow anterior chamber whereby the iris and the front of the cornea come into contact obstructing the flow of the aqueous fluid from draining.

Figure 5. Closed Angle Glaucoma

Treatment

This type of glaucoma should be treated immediately at your local hospital to relieve the pressure and pain. Medication will be required to reduce the aqueous production in the eye and improve its drainage. The long-term treatment would involve surgery; this would usually be done by laser treatment, which is not painful. If closed angle glaucoma is left untreated it may cause loss of sight in the affected eye however if treated promptly the recovery of vision will be more or less undamaged and permanent.

Secondary Glaucoma

Open angle, closed angle and congenital or developmental glaucoma are all known as primary glaucoma’s as these are not related to any other ocular disease. The most common causes of secondary glaucoma’s include inflammation of the iris (Iritis), Hyphaema where blood may have been present for some time in the anterior chamber, Iridodialysis; detachment of the iris from the ciliary body, or post cataract surgery.

Treatment

Initial treatment for secondary glaucoma is to control the underlying condition.

Congenital Glaucoma

Congenital or developmental glaucoma is very rare but potentially serious in babies. This condition is caused by a malformation in the eye and is often determined genetically. Early signs of a raised intraocular pressure (IOP) in infants are excessive flow of tears and extreme sensitivity to light (Photophobia). This condition tends to be slightly more common in boys than girls. Visual field loss and stretching of the ocular tissues will cause myopia (Short sighted vision) as a result of the raised IOP.

Treatment

Congenital glaucoma must be treated with surgery to dissect the drainage channels to allow for a continuous flow of aqueous fluid.

Driving with Glaucoma

The Driver and Vehicle Licensing Authority (DVLA) state that people driving must meet the recommended national guidelines for visual fields when diagnosed with glaucoma by an Ophthalmologist. A visual field test is preformed during or following an eye examination where small spots of light are randomly shown on a screen for you to confirm which can be seen, any points missed will be plotted on a field of results sheet for your ophthalmologist to review. Assuming the loss of visual field is not too advanced driving will still be possible, you will need to confirm this with your ophthalmologist or obtain a leaflet about driving from The International Glaucoma Association (IGA).

Conclusion

Regular eye examinations are fundamental for the health of your eyes and vital for controlling serious visual loss from Glaucoma, early detection and treatment are key for the prevention or slow down of further damage by glaucoma. If low vision aids are required your optician or optometrist can advise you of the best solution and whether you would be eligible to register as sight impaired (partially sighted) or severely sight impaired (Blind).

Need further advise?

The Royal National Institute of Blind People (RNIB) offers a Helpline for advice and products from both RNIB and other organisations. If you need to know more about your eye condition they are only a call away.

RNIB Helpline
Tel: 0303 123 9999
Email: helpline@rnib.org.uk

The Royal National Institute of Blind People (RNIB) is available Monday to Friday 8.45am to 6.00pm and Saturday 9.00am to 4.00pm. If calling outside of these times a message can be left and they will get back to you as soon as possible.

Unfortunately, RNIB can only answer email enquiries from within the UK. But you may find an organisation for people with poor sight in your country through their agencies database.

Useful contacts

Royal College of Ophthalmologists
The Royal College of Ophthalmologists is unable to comment on individual patient care.

The International Glaucoma Association (IGA)
Woodcote House
15 Highpoint Business Village
Henwood
Kent
TN24 8DH
IGA SightLine: 01233 64 81 70

Driver and Vehicle Licensing Agency (DVLA)
Drivers Customer Services (DCS)
Correspondence Team DVLA
Swansea
SA6 7JL
Tel: 0870 240 0009

Partially Sighted Society
Queen’s Road
Doncaster
DN1 2NX
Tel: 01302 32 31 32

National Glaucoma Research (USA)
American Helath Assistance Foundation

All words and illustrations by Tony Russell, SelectSpecs.com

Gordon Brown recently had his annual eye check up at Moorfields Eye Hospital in London, a statement from 10 Downing street said that surgeons discovered two tears to his retina of his remaining good eye.

Mr Brown said “I had been to see my doctors, they looked at my eyes. I did have a lot of operations when i was young, i went through quite a difficult time. They managed to save my eyesight and it is not deteriorating, everything is fine”

Further operations are not required as surgeons have found no deterioration or no significant change to his vision.

To view the original BBC interview click here

Moorfields Eye Hospital treat over 270,000 patients a year across the entire range of ophthalmic specialties. And in partnership with the Institute of Ophthalmology, Moorfields Eye Hospital also lead the world’s most extensive ongoing ophthalmic research program, achieving the highest possible score in all recent assessment ratings.

Retinal Detachments

A detached retina is the separation of the neural layer from the underlying supportive tissue, this may only affect a small area or be very extensive, nonetheless this is a serious and sight-threatening event. If the retina is not reattached soon after detachment, sight may be lost as the retina cannot operate with these layers detached.

Source: All About Vision

As the retina detaches the patient may notice flashes of light when moving their eyes around, they may also experience ‘floaters’ which move with the eye and then settle as the eye rests, this may be due to a Vitreous detachment which often proceeds a retinal detachment. The Vitreous is a transparent gel substance filing the back of the eye ball. Another sign of a retinal detachment is the patient will notice a progressive loss of visual field as a shadow or a curtain descending from the top of the eye or across from the side.

These signs may be progressive, developing slowly as the retina separates from the supportive tissues or this can occur without warning if the retina detaches immediately.

Retinal detachments can cause irreversible loss of vision if not treated immediately. If you experience any of these signs consult your optician right away or if in doubt go straight to A&E (Casualty) for urgent treatment, your odds of recovering loss vision will increase with immediate action.

Treatment for Detached Retina

Retinal tears can be treated with a laser by sealing off leaking blood vessels and destroying new blood vessel growth, however if the area of the detachment is large surgery may be required.

For more information on Retinal detachments, causes, symptoms, signs, and treatments visit these links below:

Detached Retina at All About Vision

Wikipedia

Royal College of Ophthalmologists

Andrew Marr’s interview with Gordon Brown at the BBC

It sounds like science fiction, but it is a great sign of what might actually be possible in the future. Ron, who is in his seventies had the experimental surgery seven months ago and now says he can follow white lines on the road and even sort out his socks thanks to his new bionic eye.

Ron’s wife is especially pleased, saying “I’ve taught him how to use the washing machine and away he goes. It’s just the ironing next.”

Image Source: National Geographic Society

The eye, known as Argus II uses a camera mounted on some stylish sunglasses to capture images which it then sends wirelessly to a tiny receiver which has been surgically attached to the outside of the eye.

The data is then sent from the receiver on the outside of the eye to an array of electrodes which have been attached to Ron’s retina.  The retina at the back of the eye is very sensitive to light.  When the electrodes attached to the retina are stimulated they send messages along the optic nerve to the brain, which is able to perceive patterns of light and dark spots corresponding to which electrodes have been stimulated.

So far 18 patients across the world have been fitted with the bionic eye – developed by US company Second Sight. The device is designed to help people who have become blind through retinitis pigmentosa, a group of inherited eye diseases that cause degeneration of the retina over a number of years.  An estimated 20,000 to 25,000 people are affected by the disease in the UK alone.

The bionic eye may not be able to help its user read fine text yet but it is a very promising sign for the future.  So far the implants have been stable and functioning for six months.  There are still another two years of the trial to run.

Ron’s story will be featured on tonight’s episode (4th March 2009) of Inside Out at 19:30 on BBC One.

For more on this story visit the BBC News site and to find out more about how the surgery/technology works go here.

Further Reading: -

• Trials for ‘bionic’ eye implants  - A nice article on the BBC News site with more details about how the technology works with images.
• Bionic Eye ‘ Blindness Cure Hope’
• A news clip from the BBC of another patient in the US with the same experimental surgery

• Cornea
• Aqueous
• Iris
• Crystalline Lens
• Sclera
• Choroid
• Retina
• Vitreous
• Optic Nerve

To read more, please view the article found here: glasses guide – guide to buying glasses online