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Solar Eclipse

O14 November 2012 - Australia and New Zealand will be exposed to a solar eclipse.
Cairns, Queensland will experience a total solar eclipse.
An eclipse occurs when the moon, partially or totally, passes over the sun.

On 14 November 2012 - Australia and New Zealand will be exposed to a solar eclipse.
Cairns, Queensland will experience a total solar eclipse.

An eclipse occurs when the moon passes in front of the sun, a solar eclipse can be partial, annular or total.

Safely watch the solar eclipse ONLINE at the following places: 

http://www.ustream.tv/cairnseclipse2012

http://www.facebook.com/PanasonicEclipseLiveBySolarPower/app_435671416492320

Risk of Exposure

Looking directly at the sun at any time is never recommended because of the risk of retinal damage and the same applies during an eclipse.

During most of a solar eclipse, at least part of the sun's rays remain visible, therefore the sun's rays can burn the eye's retina if a viewer looks directly at the eclipse.

The retina is the delicate lining at the back of the eye that contains layers of light-sensitive nerve cells used for seeing.

Retinal burns cause a temporary or permanent vision loss based on the degree of exposure.

Light-induced retinal injuries can occur without any feeling of pain and the effects of the injuries may not appear for at least several hours after the damage is done.

The Sun’s reduced radiance during an eclipse makes it far more dangerous than a transit of Venus where the sun’s radiance is reduced by only one per cent.

During partial eclipse phases our normal “aversion response” to the bright sun is reduced risking prolonged, unprotected, direct viewing and eye damage.

It is important to recognise the dangers of looking directly at the eclipse.

There are risks associated with all forms of direct viewing; solar filters, unprotected viewing or viewing through optical instruments.

 

Solar Retinopathy

Solar Retinopathy can be divided into two clinical entities.

There is no recognised treatment for either so prevention is paramount.

True retinal burns (thermal) occur when looking through an optical instrument concentrates the Sun’s rays.

The father of modern astronomy, Galileo Galilei and laser retinal surgery pioneer Gerhard Meyer-Schwickerath both suffered lesions from solar viewing with a telescope.

Photoretinitis (phototoxic) from direct viewing of the sun represents the majority of cases.

There is considerable variability in susceptibility between individuals which is not fully explained.

Such factors as age, pupil size, ocular pigmentation, photosensitising drugs, recreational drugs, alcohol, antioxidants and macular pigment density have been proposed.


Children are at most risk

Children and teenagers are most vulnerable to solar retinopathy due to the transmission characteristics of their eyes, their lack of experience in using solar filters and incomplete understanding of the dangers.

Children need special protection from direct viewing and it is good general advice to use indirect viewing methods.

 

Safe Viewing

Indirect viewing with the back turned to the eclipse or

viewing live streams via the internet are the only safe methods endorsed by the Royal Australian and New Zealand College of Ophthalmologists (RANZCO).


'Turn your back to the eclipse'

  • Viewing the eclipse can cause permanent visual loss;

  • damage occurs rapidly without any pain;

  • loss of vision does not occur until after the eclipse;

  • there is no treatment;children are especially at risk.

  • The ASO advises against any direct viewing of the eclipse.

Read the article by Dr Rowan Porter written for the ASO Bulletin September 2012 - Turn your back to the eclipse

A number of research articles have been published which show incidence of retinal damage from viewing solar eclipses click here.


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Media: 7 November 2012, Courier Mail, 'Australian Society of Opthalmologists say people risk eye damage looking at solar eclipse even with approved solar glasses'

Useful links:

CSIRO Safely viewing the sun

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