[Basic] Disadvantage of the Week: No Depth Perception and One Eye

[johndallman]

No Depth Perception [-15] and One Eye [-15] are mundane physical disadvantages, with the same basic effect, a lack of binocular vision. With One Eye, you had two eyes, but have lost one, or your species naturally has only one eye. With No Depth Perception, you have two eyes, but their fields of vision don’t overlap, you have a vision disorder that means only one of your eyes is useful, or your brain doesn’t handle two eyes effectively. In any case, you can only have one of these disadvantages, unless you have a good excuse, such as two heads. Both these disadvantages appeared during the 3e period: No Depth Perception in Compendium I and One Eye in the 3e Basic Set.

The lack of binocular vision imposes significant handicaps for adventuring: -1 to DX in combat and for all tasks involving hand-eye coordination, and -3 on un-Aimed ranged attacks and for operating any vehicle “faster than a horse and buggy.”

If you’re missing an eye, you can wear an eye patch, or a glass eye. The latter should mitigate the loss of a level of Appearance that some cultures impose for an obvious missing eye. If you start play with One Eye, that’s already built into your existing Appearance level.

One Eye is a fairly common disadvantage on published templates for experienced warriors, and also shows up on Cyclopes, Meyhom and other monsters who are severely distorted people. Action points out that night-vision and thermal-imaging goggles impose No Depth Perception. Bio-Tech allows replacing missing eyes, which cures relevant disadvantages and can add advantages, and DF 15 Swashbucklers has a far more cinematic way of overcoming One Eye. Madness Dossier has drugs that can confuse your brain to give No Depth Perception, and Enhanced Senses delves into binocular vision in more detail. Several Reign of Steel robots have One Eye (a single camera), and Tactical Shooting has tactics for using one eye at a time in rapidly varying light levels. Ultra-Tech has bionic eyes, and makes it easy to lose an eye to laser damage.

I have No Depth Perception, because my brain ignores one of my eyes unless the other one is closed. The penalties seem plausible, after a lifetime of reality-checking them. With those added to less-than-wonderful DX, my driving instructor advised me to give up, because I was frightening him.

I’ve poked a few monster’s eyes out in GURPS combats, but I’ve never seen a PC with either of these disadvantages. Have they been seen in your games?

[WingedKagouti]

I haven't seen either on a PC in a game, most likely due to the combat penalities. But One Eye feels like such a classic trait for pirates and other rough combatants that I'd be surprised if no one has ever seen it used.

[Celti]

Originally Posted by johndallman

I have No Depth Perception, because my brain ignores one of my eyes unless the other one is closed. The penalties seem plausible, after a lifetime of reality-checking them. With those added to less-than-wonderful DX, my driving instructor advised me to give up, because I was frightening him.

As someone born with the same condition, the penalties seem rather off to me. I have just about zero trouble with hand-eye coordination and combat (well, Combat Sport — SCA-flavoured) at any range below about fifteen feet.

Beyond there, the -3 to unaimed ranged attacks is reasonable, and I would say that the -1 applies even when Aiming for any significantly arcing attack — e.g., throwing a rock is a pain at any distance, firing an arrow is difficult at a moderate range, and firing a gun is fine until much longer runs.

Driving was initially somewhat difficult, but I rapidly learned to compensate — nowadays I think I would only have trouble with deliberately skewed or falsified perspective cues, e.g., scaled-up or -down vehicles, or driving on the Infinite Featureless Plain that some people insist GURPS combat must take place upon.

Perhaps I've partially bought off the disadvantage through training?

[Phil Masters]

Originally Posted by WingedKagouti

I haven't seen either on a PC in a game, most likely due to the combat penalities. But One Eye feels like such a classic trait for pirates and other rough combatants that I'd be surprised if no one has ever seen it used.

No, "Eye Patch" is a classic feature for pirates and the like. Has anyone ever seen an action story where a character missing an eye was actually disadvantaged by the effect? Nick Fury has been through 50+ years and two incarnations with eye patches while habitually shooting the wings off flies from the backs of speeding motorcycles...

Thought; should most herbivores and suchlike species with Peripheral Vision also have No Depth Perception by default? With eyes on either side of their heads, they must be getting very limited overlap in fields of vision, by and large. Of course, they rarely operate missile weapons or vehicles in the world we know, and tend to privilege flight over fight generally, so it's not like the effects would be obvious or severe.

Data point; I have mangled vision in my left eye (detached retina, repaired but far from perfectly -- it was the curse of Thaumatology), but I think I still have about 90% functional depth perception.

[Flyndaran]

I would think that the reduced field of view would cause more problems for someone fully used to one eye than the loss of stereoscopic vision.
It's not like that part can be compensated for with practice other than maybe by always bobbing one's head around like a bird.

As another anecdote:
My mom and I once played catch with one eye closed. After a few minutes of fumbling, I was no clumsier than I am normally, though admittedly that is still pretty clumsy.

[whswhs]

Originally Posted by Phil Masters

Thought; should most herbivores and suchlike species with Peripheral Vision also have No Depth Perception by default? With eyes on either side of their heads, they must be getting very limited overlap in fields of vision, by and large. Of course, they rarely operate missile weapons or vehicles in the world we know, and tend to privilege flight over fight generally, so it's not like the effects would be obvious or severe.

As it happens, GURPS Powers: Enhanced Senses goes into this in detail on p. 16, as part of "Fields of View and Extra Eyes."

[Bruno]

The penalty to fine motor skills seems the most sketchy part of the writeup to me. How much depth perception is involved in being a mechanic? Or painting a miniature?

On the other claw, I can see it having an interesting (not necessarily negative) impact on arts with a significant visual element - but only sometimes, depending on the artistic style in vogue. Before the obsession with perspective and realistic proportions, I'm not sure how much it would actually matter.

I am playing a character with a modified (reduced) version of No Depth Perception, eliminating the -1 to DX for melee combat within one yard. 2 yards+ still penalized. We called it [-10]. It definitely feels like a leveled version of this trait would see more use, -15 point traits are pretty severe. He is, of course, a minotaur, with a proper bulls head instead of the "sorta human" head many minotaurs get depicted with.

[Plane]

Someone who actually has their eye gouged out, aside from probably having an "open wound" (forget the name of that trait) should probably be mechanically different from a species born with one eye...

Primarily because stuff like a cyclops has a centered eye (equal ability to look left and right) whereas humans who lose an eye do not have an equal left/right ability: they would be able to see better on one side than the other.

What's a good way to do that?

[TGLS]

Originally Posted by Plane

Someone who actually has their eye gouged out, aside from probably having an "open wound" (forget the name of that trait) should probably be mechanically different from a species born with one eye...

Primarily because stuff like a cyclops has a centered eye (equal ability to look left and right) whereas humans who lose an eye do not have an equal left/right ability: they would be able to see better on one side than the other.

What's a good way to do that?

Maybe copy tunnel vision/no peripheral vision and just call which way the arc points a feature?

[Bruno]

Originally Posted by Plane

Someone who actually has their eye gouged out, aside from probably having an "open wound"

Wounded is only really appropriate in a pre-modern game, and even then, someone who actually has a chronic open wound in the eyesocket in a pre-modern society is basically going to die of infection Right Quick Like unless they're absurdly lucky.

The eyelids can end up fusing to the damaged tissues and effectively sealing the wound even on their own, although this is far far more likely if assisted with a minor surgery (and basic wound care). We've actually been capable of this surgery for a very long time, you just want the modern era for a sterile operating environment, antibiotics, anaesthesia, and other little luxuries like that.

Infection in an open eye socket has a highway to the brain via the optic nerve, it does not, as they say, have a positive prognosis.