Correct English is:

Sunglasses are a type of glasses which protect our eyes from sunlight. OR

Glasses that protect our eyes from sunlight are called sunglasses.

Should be a capital "S" at the beginning of a sentence.

Why is there a colon in the sentence?

Sunglasses are plural, so therefore "are" is used.

To use "type" is better than "kind".

There is no hyphen in sunlight.

First sentence is write because sunglasses are always plural only, it doesn't have singular one. The sentence contain small mistake it should be sunglasses are a kind of glasses which protect our eyes against sunlight. I use a here because from kind of glasses sunglasses are one kind thats why.

There are some items having two parts that are treated as plural in English even though really only one item. Scissors, shears, pliers, pants, trousers, shorts, eyeglasses, sunglasses. These are always treated as plural. However they're sometimes preceded by "a pair of" (a pair of trousers) when referring to one item. When "a pair of" is used, then they're treated as singular. "Here are the scissors." "Here is a pair of scissors."