This but as a spell at what 1st level that gets better at higher level.

No. 1st level spells don't do stuff like this.
It's an item for a reason

in general the big balance between items and spells is duration, and resource management. a 1st level spell that gives you advantage on visual perception checks for a minute or less wouldn't be that broken, the bonus of the item is that it is a continuous effect that uses no resources.

no 1st level in the game gives adv on important checks.
so yeah

What you could do if you're a DM is make it so that all ranged weapons gain a +10/+20 to their range. So a hand crossbow would have a range of 40/140 instead of 30/120.

Quote from Cappuls >>

What you could do if you're a DM is make it so that all ranged weapons gain a +10/+20 to their range. So a hand crossbow would have a range of 40/140 instead of 30/120.

 Or you as a player take sharpshooter feat and a longbow or heavy crossbow or one of the guns from gunslinger and just ignore it.
Longbow would be 600 feet easy shoots, you should be able to get 10 rounds before whatever you are shooting at is in melee if they run and dash every round and your DM ignore the 3 dash in a row rule.
With heavy crossbow you would deal more damage at 400 feet range.

Quote from Ghepip >>

Quote from Cappuls >>

What you could do if you're a DM is make it so that all ranged weapons gain a +10/+20 to their range. So a hand crossbow would have a range of 40/140 instead of 30/120.

 Or you as a player take sharpshooter feat and a longbow or heavy crossbow or one of the guns from gunslinger and just ignore it.
Longbow would be 600 feet easy shoots, you should be able to get 10 rounds before whatever you are shooting at is in melee if they run and dash every round and your DM ignore the 3 dash in a row rule.
With heavy crossbow you would deal more damage at 400 feet range.

 There is no 3 dash in a row rule that I have ever heard of in 5e.

It’s in the Dungeon Master’s Guide under chase rules. I think it’s the DMs call about whether or not that rule applies outside of chases. 

Enhance ability would be the spell for this.  Not 1st level

I have a question about this item.

Suppose that a character naturally has Darkvision, 60' or more. This item allows for detailed vision from far away. Do these features stack?

I would say no, there are objects or feats that allow you to see beyond 60 feet away, for example goggles of night. Also remember that in a slightly darkened area, creatures have a disadvantage on Wisdom (Perception) checks that are based on sight. If you don´t have darkvision but you have this giving you an advantage, they would cancel making your roll normal.

How would wearing these impact a Kobold's daylight disadvantage?

I really wish this item was more specific than "extremely distant"
Like can you see good at 2 miles? 1 miles? Farther?

Hello I'm not sure if anyone has said this yet but does this item interact with kobolds sunlight sensitivity?.

Also would it turn the disadvantage in sunlight to a straight roll when looking at a target or creature in direct sunlight.  While either pc or target or both are in sunlight?.

Would that then turn to advantage when targeting something or perceiving it when both are inside?.

Quote from Abyssnorth >>

Hello I'm not sure if anyone has said this yet but does this item interact with kobolds sunlight sensitivity?.

Also would it turn the disadvantage in sunlight to a straight roll when looking at a target or creature in direct sunlight.  While either pc or target or both are in sunlight?.

Would that then turn to advantage when targeting something or perceiving it when both are inside?.

Yes. If you have both advantage and disadvantage for any type of check, then they cancel each other out and you do a straight roll.

And indoors the kobold with goggles would indeed have advantage, unless something else cancelled it out with disadvantage.

Why does it requires attunement exactly while other eyewear don't? just curious.

What is the attumement for it?

What's the distance on these things? Am I supposed to use an actual eagle's visual capabilities of being able to spot a rabbit from 3 miles away?

The human eye can see as far as the horizon in clear conditions. You just can’t make out detail.

There is an equation (http://www.ringbell.co.uk/info/hdist.htm) you can use to calculate the distance to the visible horizon based on the height you are at above sea level. On a mostly level plane, the horizon is about 11 miles out. So your character can make out detail 11 miles away, if they have line of sight, and further the higher up they are.

At least, that’s how I rule it at my table.