Eclipse August 21, 2017

Eclipse August 21st 2017 Notice

 

Starting August 21st at approximately 9:07am, maximizing at 10:24am and finishing at 11:48am a solar eclipse will occur. Here in the desert it won’t be a total eclipse but about 70% (69%)of the sun will be obscured. Because of the infrequency of this natural phenomena and because of the publicity involved it is important to be aware of the risk of solar retinopathy with improper viewing.

 

Solar Retinopathy:

Solar retinopathy (also known as, photic retinopathy, foveomacular retinitis,solarretinitis, and eclipse retinopathy) refers to a photochemical toxicity and resultant injury to retinal tissues, commonly occurring at the fovea where the eye’s sharpest vision is.

The initial exposure can present immediately following exposure or as increasing symptoms four to six weeks after the incident. The damage is done as an oxidative process at the level of the retinal pigment epithelium (RPE) and subsequently the outer retina.

There is currently no treatment for solar retinopathy. Patients present with blurry vision, central or para-central scotomas (vision loss) and photophobia (light sensitivity).

 

How this occurs:

The wavelengths of light that are most damaging are those that can pass through the cornea and lens. Those include the longer waves of the UV-A, the visible light and the near infra-red light. This high intensity radiation is absorbed by the pigment in the RPE layer and an oxidative process damages it. The layer above it called the outer retina is also damaged. Since the RPE layer is a support layer for the retina; long term damage comes from loss of this support layer.Typically damage to the outer retinal occurs immediately in more advanced cases and more slowly in less involved cases.

 

Prognosis:

Generally patients with solar retinopathy that present with 20/50 to 20/70 visual acuity have a better prognosis and those will less damage of the retinal pigment epithelium also have a better long term outcome. Vision can improve for up to a year although it’s not uncommon to have fairly normal vision with paracentral scotomas (small areas of vision loss). Chronic solar retinopathy occurs when vision progressively gets worse after one year.

 

The best treatment is avoidance:

To ensure a save viewing experience wear ISO (international Standards Association) 12312-2 certified eclipse glasses. In America there are 5 manufacturers. They are Rainbow, Symphony, American Paper Optics, Thousand Oaks Optical and TSE-17. The eclipse glasses will be marked to ensure safety.

  • don’t wear if scratched
  • don’t wear if warped
  • don’t wear if they’re knock-off or not certified to ISO standards (these will be listed on the KMIR website)
  • there will be no totality here in the desert so you cannot watch the eclipse without risk of damaging the eyes with no protection
  • regular sunglasses do not offer protection. Eclipse glasses absorb up to 1000 times as much solar radiation

The last total eclipse visible in the US was in 1979. The next total eclipse visible in parts of the US will be April 8, 2024.

 

Sources:

timeanddate.com

Solar Retinopathy: Etiology, Diagnosis and Treatment, Chen et al, Retinal Physician October 1, 2013

2017 Solar Eclipse Public Service Announcement

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