On 8/20/2017 8:31 PM, U.S. Janet B. wrote:

>>
>> Things were a lot simpler back in the old days. People just used film leader or glass darkened with candle soot to view the sun. As far as I know there was no mass epidemic of blindness caused by viewing a solar eclipse. These days, it seen as a serious public health issue.
>
> What I have heard is a scale with partial loss of vision on one end to
> complete blindness at the other.
> Janet US
>

A couple seconds glance is not a big deal but a half hour stare would
sure do some damage.