Blindness is an inability to see. When blind, normal movement will result in you using your hands to feel for items on the ground. Unseen items only appear as their base item, without even randomized appearance - for example, you will only feel "a wand" or "a potion". Items seen prior to blinding will continue to be identified with their randomized appearance.
If you lack telepathy and move normally while blind, you attack anything you walk into as if it were invisible. This makes it very dangerous to move around, because if you move while blind you could inadvertently kill your pet or blunder into a peaceful monster.
To avoid this, be sure to move with [m] followed by a direction as this causes you to move but not feel on the ground for items or attack monsters if they are in the way. If you have telepathy or warning, using [m] to move will still cause you to attack the monster. If you are fairly confident there are no monsters on the level that could seriosly damage you in one hit you could also wait for them to attack you first. Ignoring a peaceful monster for a period may produce the message "Pardon me, foo."
Special care should be taken on levels with cockatrices on them - if there is a cockatrice corpse and you move around while blind, you may stumble on to the corpse and feel for it. This will result in stoning for characters not wearing gloves. Use [m] movement (as above) to avoid touching the corpse while moving. Additionally, if you try to [:] (look) or [,] (pick up) on a square with a cockatrice corpse while blind you feel the square and will also be stoned! Even worse, if you have telepathy or warning, the cockatrice is alive, you are blind and you have no wielded weapon and no gloves, using [m] to move will cause you to fight the cockatrice and you will be stoned...
Beware, blinded creatures do not respect Elbereth.
If you have telepathy, though, blindness can be quite useful as it enables you to see all monsters with brains on the level. Intrinsic telepathy is only active when you are blind; extrinsic telepathy will work like intrinsic telepathy when you are blind.
Ways to be blinded
In addition to this list, most of the methods to blind monsters also work onto yourself.
- Drink a potion of blindness. This is not recommended.
- Be attacked by a yellow light (preventable by wearing a blindfold or towel)
- Be attacked by a raven (preventable by wearing a blindfold, towel, visored helmet or lenses)
- Eat rotten food (one possible outcome)
- Be hit by a wielded or thrown cream pie (you can also apply one to yourself to cause the same effect)
- Apply an expensive camera at yourself
- Be zapped by (a wand of) lightning
- Engraving with a wand of lightning
- Be hit by the monster spell, blind
- Apply a cursed towel (one possible outcome)
- Be hit by blinding venom
- Polymorph into a creature that has no eyes
- Read a cursed or difficult spellbook
- Apply a cursed unicorn horn (one outcome, not recommended.)
A blind enemy will move and attack erratically, suffer a to-hit penalty and are much less dangerous, especially if you can keep moving. There are six main ways to inflict blindness.
- Apply an expensive camera. The tourist relies on this to survive early levels. Other adventurers tend to find them in the Gnomish Mines, where they may appear either in a cavern level or the Minetown hardware store. This will also cause enemies to flee.
- Zap a wand of lightning. Blinding is a secondary effect.
- Polymorph yourself or your pet into a creature with a blinding attack.
There are a few ways to cure intrinsic blindness - that is, blindness not from being blindfolded, cream pies, venom or applying cursed towels.
- You can wait for it to heal - this can take a few turns if the blindness was caused by eating rotten food or being hit by a potion of blindness, but will take many hundreds of turns if you quaffed a potion of blindness. Having read cursed/difficult spellbook takes quite a bit of turns too. If you do have to wait it out, make sure you have a good amount of food.
- Apply a unicorn horn
- Eat a carrot.
- Praying to your god may help, but be aware that blindness is only considered a minor problem.
- Astral vision does not cure blindness, but allows you to see despite it.
Otherwise, you can remove whatever it is that is blindfolding you. Having a cursed blindfold or towel stuck to your face is considered a major problem, so if it is safe to pray, your god is likely to help you out of this predicament.
It is worthwhile considering the internals of blindness, which are quite complex, but their details shed light on the actions and exceptions described above.
The source recognises three forms of blindness:
"Blinded" refers to all forms of blindness that are intrinsic; that is, you would be blind if you were not wearing or wielding anything and polymorphed into a monster form with eyes.
The number of turns for which you are blinded is recorded.
Being "creamed" means you have a substance over your eyes physically restricting your vision. It is a subset of being "blinded", and stacks with blindness.
The number of turns you are creamed is recorded. It is always less than or equal to the number of turns you are blinded.
Items causing or curing creaming affect both the number of turns creamed and blinded by the same amount.
Actions that cream are:
- Being hit by, or applying a cream pie
- Being hit by blinding venom
- Applying a cursed towel
Actions that cure creaming are:
- wiping your face
- Applying a noncursed towel
All other actions and cures affect blindness only, except prayer, which will cure both creaming and blinding, if it cures either.
"creaming" times out first; so if you are blinded for 100 turns, then 50 turns later you will still be blind for 50 more turns. If at this point you become creamed for 20 turns, you will be blinded for 70 turns, the first 20 of which you are also creamed.
"Blind" means you currently cannot see. You can be "blind" without being "blinded", if your eyes are covered by a blindfold or a towel, or you polymorph into a monster with no eyes. You can be "blinded" without being "blind" if you have astral vision.