Pupils that are always dilated -- what does this mean?

March 22, 2007 7:21 AM

People always comment that my pupils are dilated. As far as I know they have always been more dilated than other people's. But why? I have heard heaps of "reasons", but they seem pretty mythical.

Here are some things that I have heard about why I may have eternally-dilated pupils:

–I'm in some sort of permanent state of arousal
–I'm a bit more anxious than others (i.e., always in fight-or-flight mode)
–I am a more sexual person
–I am more alert than others
–I have a super-slightly slipped disc somewhere on my spine which could be corrected by a chiropractor!
–I have weak pigment in my retina (I do have problems with glare as well)
–blah blah blah

Have there been any studies done? Is there any real reason why my pupils are always dilated? It doesn't bother me, in fact I quite like it -- but whenever I meet new people I am reminded, because invariably somebody assumes that I am on drugs.

Specifically, I'll get people who confess to me a month or so after first meeting me, that they thought I was completely flaky, and it took them a while to realise I was smart, purely because they thought I was high due to my pupils.

Could this signify a health problem, even though my eyes have always been this way?

I welcome anecdotes as well!

posted by mjao to health & fitness (12 comments total)

Maybe the photoreceptors in your eyes are unusually weak?
posted by b1tr0t at 7:27 AM on March 22, 2007

Assuming you're not a coke head, I remember reading in some bio textbook that different people have different baselines as to how dilated their eyes will be in normal light. That said, assuming your eyes are not dilated different amounts (which I think can be a problem), it wouldn't hurt to casually ask a doctor you know, or even better, an ophthalmologist you know about this. It sounds like something they could answer off the cuff.
posted by jourman2 at 7:32 AM on March 22, 2007

my eyes are always heavily dilated, its for the reason b1tr0t stated.

i do have an eye disease which causes this though.
posted by moochoo at 7:35 AM on March 22, 2007

My son's pupils always seem very dilated to me, too. (He's almost 6.)

Ancedote: Sometimes when we take pictures of him, he'll have really strange red-eye - his entire eye will appear orange. There have also been times when, just looking at him at a certain angle in a certain light, it'll look like he has red eye.

(Or maybe that just means he is the embodiment of evil. I'm not ruling that out yet.)
posted by Lucinda at 7:52 AM on March 22, 2007

Oh I forgot to add, I am myopic! +2.25 lenses in each eye. Are the two correlated?

jourman2, I do remember asking my optometrist when I was a teenager but his answer was the "weak pigment in retina" one. He didn't seem terribly interested. I still wonder though!

b1tr0t, moochoo, if the photoreceptors in my eyes are unusually weak, do you know if this would result in anything else other than dilated pupils/problems with glare? i.e., does it have any other effect?
posted by mjao at 7:52 AM on March 22, 2007

People's pupils are different sizes as well. I have extremely large pupils, so my pupils will always look larger than other people's. This could also play a role in your pupils' looking dilated.

As for weak photoreceptors, that would suggest that it takes more light for you to see than a normal person, which would explain why your pupils are more dilated because dilation allows more light to come into your eyes. This would probably also result in a reduced sensitivity to contrast, so when two things are very similar in lightness, you could confuse them more than a normal person. It would also make it harder for you to see in the dark, because you need more light to make your photoreceptors work, and since at normal light levels you are more dilated than normal people, you have less range.
posted by JonahBlack at 8:15 AM on March 22, 2007

mjao - no disrespect to optometrists, they're really good at what they do, but I'd try to find an ophthalmologist that can answer a question or two about your eyes. They just have so much more formal and in depth training than optometrists. That would be my course of action.

full disclosure - my dad is actually an ophthalmologist, if you'd like me to email him this question, email is in the profile.
posted by jourman2 at 8:41 AM on March 22, 2007

I too also have pupils that are noticeable large. This is also true (and always has been) for my father's mother. Neither she nor I have any identified eye problems.

So, I've always written it off to a hereditary difference in baseline pupil size.
posted by divka at 9:49 AM on March 22, 2007

Mine are noticibly large, too, and the delivering doctor commented on them when I was born. I've never found out a proper reason behind it, so I assume it's just one of those differences people have.

Other than the horrible blinding glare of sunlight, I haven't had any health problems related to them. My vision is better than a lot of people with 'normal' pupils.
posted by cmonkey at 10:02 AM on March 22, 2007

So, some googling brought me to the merck manual which has the comment on pupil size

Pupil Size: Normally, both pupils (the black area in the middle of the iris) are the same size. Pupils become large (dilate) in the dark and become small (constrict) in bright light. Although some people have much larger pupils than others, large or small pupils by themselves do not necessarily indicate a problem or abnormality. The pupils tend to become smaller with age. Constricted or dilated pupils may be caused by certain drugs used to treat eye diseases. Pupil constriction may be caused by opioid drugs, such as morphineSome Trade Names
MS CONTIN
ORAMORPH
. Pupil dilation may be caused by amphetamines, antihistamines, cocaine, and marijuana. Small, irregularly shaped pupils may be caused by syphilis.

Unequal pupils (one large and one small) may be caused by conditions that affect one eye differently than the other. Such conditions may include injury or inflammation of the eye, injury of the nerves that control the pupil, head injury, brain tumors, and using eye drops in only one eye. Rarely, a person is born with pupils of different sizes.

During a complete eye examination, doctors shine light into each pupil, which causes them to constrict. No treatment is needed to modify pupil size.
posted by jourman2 at 10:58 AM on March 22, 2007 [1 favorite]

That's kind of strange that people pay such attention to pupils.. I've honestly never been interacting with someone and thought "Oh what dilated pupils they have."

I'm not an expert, but I wouldn't be too concerned about it. You could certainly pursue an answer with an actual eye specialist. I tend to ask doctors questions to satisfy my curiousity.
posted by VegaValmont at 12:01 AM on March 23, 2007

Since nobody else mentioned this - this is a variance that is apparently common enough that the ads and things for colored contact lenses make mention of it as a possible problem for some wearers. While that doesn't speak to cause it does, imho, imply there's just a plain-old physiological variation in the population.
posted by phearlez at 10:14 AM on March 23, 2007