This little shrine is Meyami Jizo (めやみ地蔵). Me-yami means sicken eyes in Japanese and Jizo is one of the Budhisattvas that is commonly believed in as a guardian god for children.

Meyami Jizo is a Budhisattvas for eyes and people who have problems with their eyes come here to pray.  

People write their wishes and symptoms on the Ema with the letter "め" (Me means eyes in Japanese) for hoping to cure it. In Edo period this guardian was considered as eye doctor and people came for cure even from outside of Edo.

This Jizo is also known as a "child raising" Jizo (Komamori Jizo) for those who wish their children's healthy growth.

This shrine has no Saisen Bako (contribution box). Can you see the little door behind the flag? That's where the Jizo is and you just throw the money inside the door. While I was watching this shrine, a woman came, stopped, threw the change in, prayed then walked away.

it seemed to be a guardian Jizo in the neighbourhood.  

One curious thing about Meyami Jizo is this wooden wheel on the side of shrine.

It's said that this wheel is connected to the Jizo with a cable under the ground and when you turn the wheel, your wish gets delivered to Jizo directly.

But how do you use it?

You just need to turn it towards you about three times. In theory one turn has the same effect as you read the sutra once although it's not so reliable. It might be just a tradition.