Dim Vision

Curses a group of monsters, reducing their vision radius.

Player vs Player: This curse will not work on other players.

This will not work on Super Unique Monsters and Bosses.

Dim Vision is useful against Ranged Attackers such as Dark Archer or spell casters with dangerous ranged spell attacks.

Dim Vision will prevent monsters from seeing you which will allow you to attack them from a distance, but they will be unable to hit you back. It's also useful to cast on a monster to limit their ability to follow you so that you can escape.

Dim Vision will not overwrite a monster Cursed with

Attract or

Confuse (but can be overwritten by them).

A monster with

Dim Vision that is attempting to close into melee range with a target will continue doing so indefinitely until it hits an obstruction of some kind (if you cast

Dim Vision on a creature that is attempting to close to melee range with you, it will continue following you, even if you move, until it hits an obstruction of some kind).

Dim Vision prevents the AI controlling the unit from deciding on a new course of action (apart from melee attacking something that's in range). This explains why, when

Dim Vision (or a

Dim Vision-like effect) overwrites

Terror (or a

Terror-like effect), the affected creature will continue running away indefinitely until it hits an obstruction or the

Dim Vision effect wears off.

Dim Vision also generally prevents monsters from using their special attacks and abilities. This means that

Blood Lord cannot cast

Frenzy, for example. (Similarly,

Vile Mother cannot create spawns,

Frozen Horror cannot cast

Arctic Blast, etc.) The only exception appears to be that if the creature's only attack is a ranged attack (such as Burning Dead archers), it can still use that attack against creatures in melee range.

Oblivion Knight in the

Chaos Sanctuary are immune to

Dim Vision. This can be quite frustrating since they can fire

Bone Spirit through their blinded companions. Switching to

Decrepify against these creatures and/or resummoning your Golem next to them is usually your most effective strategy.

Dim Vision is especially great on Hardcore mode. With maxed-out

Dim Vision and some +skills items, you can hit more than the entire screen. If you take care you will never face a normal enemy that can see you. It's also helpful in a party setting since

Dim Vision makes many melee monsters less fearsome by disabling their

Charge &

Frenzy-type skills and ensures that melee party members can run away and heal for a bit if things get too intense.