Sudden sun-blindness

Can someone explain the strange occurrence I had when sunbathing (in the shade) on a beach. I sat up to find that my vision was totally blurring in a way that you see on ET-type movies when people and objects become just bright blue and red shadowy figures surrounded by bright white light?  This lasted for around 5 mins before my sight returned to normal.  I was wearing sunglasses at the time,

[John C Hagan III, MD, FACS, FAAO]

The sunglasses likely did not adequately protect the eyes.

Should it reoccur without sunbathing see an Ophthalmoloigst

JCH MD