Thread: Lens Fungus
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Old 29th June 2016
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Re: Lens Fungus

Originally Posted by Ricoh View Post
Eyes are not 'designed' (ie have not evolved) to look at light, but to see with (reflected) light.

Normal incandescent light sources are better for the purpose (old style torchlight) and your recommendation for viewing oblquily is the best advise if you must look at a light source.

As for LEDs which emit in the near IR (such as those used for pointing) the retina can be damaged easily - no blink response, or reduced, and focused near perfectly on the retina.

I worked with equipment that emitted in near IR and apart from having to wear eye protection I had regular retinal scans - mainly for the benefit of the company, some suggested!
This is an interesting point. LED's emit a very narrow bandwidth of light, (it is an electrochemical reaction after all). I can imagine that LED's emitting near infra-red light could do a lot of damage before anyone realises.

White LED's try to cover the entire visible spectrum by using multiple chips, but most cheaper devices emit very little in the infra-red or near infra-red spectrum; hence their horrible colour rendition. Many cheaper devices also tend to emit of a lot of light in the green spectrum as the eye is most sensitive in this region.

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