Wikipedia:Reference desk/Archives/Science/2006 September 6

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September 6

Ejaculation

Is there any way of shortening the "refill time" after I've ejaculated semen from my penis? Do any of those pills you see advertised on the internet that claim they do this really work?

The "refilling time" you refer to is called a refractory period Raul654 00:30, 6 September 2006 (UTC)

Also, from that article, The refractory period varies widely between individuals, ranging from minutes to hours. An increased infusion of the hormone oxytocin during ejaculation is believed to be chiefly responsible for the refractory period and the amount by which oxytocin is increased may affect the length of each refractory period. Another chemical which is considered to be responsible for this effect is prolactin, which represses dopamine, which is responsible for sexual arousal. So I suppose any enzyme that breaks down either prolactin or oxytocin could theoretically decrease the time of a sexual refractory period. Raul654 00:32, 6 September 2006 (UTC)

Perhaps training yourself to need less time will work. --Proficient 04:12, 6 September 2006 (UTC)

What sort of training did you have in mind?--Light current 18:00, 6 September 2006 (UTC)

I consider myself an expert in the field and would definetely recommend "milking" which would induce your body to keep up with the demand. - Tutmosis 01:26, 7 September 2006 (UTC)

Can you eleaborate?--Light current 14:31, 7 September 2006 (UTC)

Its very simple, milking is forced (A.K.A planned & executed) masturbation a number of times a day to force your body to increase sperm production as well as the rate. Years of training will give you results so great that you will even forget what being "dry" means. - Tutmosis 00:36, 8 September 2006 (UTC)

OK thats assuming you can do it more than once a day. You must be a youngster! Enjoy it whilst you can! 8-)--Light current 00:38, 8 September 2006 (UTC)

I have to admit I dont have the swing I used to have but I'm sure with hard work and devotion we can all "spray the goodness" again. - Tutmosis 00:48, 8 September 2006 (UTC)

o_o --Froth 20:27, 8 September 2006 (UTC)

TMI Raul654 20:35, 8 September 2006 (UTC)

AS long as youre not doing it whilst editing, I can deal with that! 8-)--Light current 00:50, 8 September 2006 (UTC)

Sticky keys ? :-) StuRat 13:48, 12 September 2006 (UTC)

THats OITE for WP!--Light current 15:43, 12 September 2006 (UTC)

OITE ? StuRat 15:29, 13 September 2006 (UTC)

One in the eye 8-) (my own abbreviation)--Light current 19:33, 13 September 2006 (UTC)

Mouthwash, alcohol, toxicity, &c.

I hold in my hand a travel bottle of Scope® mouthwash, a generous, easily-confiscatable gift from the good people at Continental Airlines. In the air, I wondered out loud whether one could obtain more alcohol from the bottle of Scope than from the little bottles of wine they were giving out. I also secretly suspected the Scope would be less sweet. I was thinking of the old comedy trope of the high school kid getting wasted on Listerine or the Vietnam veteran hooked on cough syrup. But, as I discovered a minute later, the label advises any unlucky ingester to contact a poison control center immediately. This Scope contains 15% alcohol by volume, as well as water, glycerin, "flavor", polysorbate 80, sodium saccharin, sodium benzoate, cetylpyridinium chloride, benzoic acid, blue 1, and yellow 5. Presumably cetylpyridinium chloride is the toxin, but in what concentration does it pose a threat to the human body? I remember, as young children, my brother and I unwittingly drank brimming Dixie cups of the stuff, not realizing the idea was to spit it out. Nor can I recall suffering any ill effects. I ask someone with a knowledge of chemistry: Is the Listerine lush an inaccurate or outdated trope (perhaps due to an advance in mouthwash technology), or alternatively, has the toxicity of mouthwash been exaggerated, perhaps to prevent lawsuits and substance abuse? Bhumiya (said/done) 04:59, 6 September 2006 (UTC)

Here's what Straight Dope says: [1] -- Scientizzle 05:19, 6 September 2006 (UTC)

Interesting. Thanks for the quick response. Bhumiya (said/done) 05:30, 6 September 2006 (UTC)

And wow, who would ever think of replacing mouth wash with pure vodka with a little food coloring???

I'm surprised that nobody has mentioned that there are two kinds of alcohol, and that the industrial cheaper kind is POISONOUS and will send you blind. I have often heard on the BBC news of people in India and elsewhere who drank cheap alcohol without being aware it was the industrial kind and went blind. The industrial kind is also that found in chemistry labs. It may also be the alcohol in mouth washes - so I wouldnt drink it. The two types of alcohol do have different names but I cannot reliably tell you what they are. 81.104.12.107 20:19, 10 September 2006 (UTC)

methanol is the industrial alcohol and ethanol is the alcohol found in drinks

As far as I know, pretty much all mouthwashes use ethanol. — Dark Shikari ^talk/_contribs 01:13, 14 September 2006 (UTC)

Genetic Gender

Why do some couples have say three girls, whilst other have three boys? Is this just the luck of the draw, or is there something else going on, like a genetic leaning toward having children of a certain sex?

See Sex ratio, Sex-determination system and XY sex-determination system for the genetics behind it. It's essentially the luck of the draw, as I understand it. --Robert Merkel 09:14, 6 September 2006 (UTC)

Statistics is one of the least understood things (alas, because a good understanding of it is essential to understanding the world around you). Having 10 children of the same gender sounds so unlikely that the couple that had them would probably think there was something special going on. But the chances are 1 in 512, which makes it likely that once in a while it will happen (if there are enough cuples that have 10 kids, that is). But then people will think that the fact that it happened to them specifically is significant. It isn't. No-one would think anything of having 3 boys and 7 girls in a specific order, but he chances are exactly the same. DirkvdM 09:52, 6 September 2006 (UTC)

"The chances are exactly the same" — that's true, but when most people say that MMMMMM looks more un-random than MFFMFM, they usually mean something more akin to "the odds of getting a non-homegenous pattern are much higher than getting a homogenous one", which is true. Unfortunately I doubt most people know that's what they're actually referring to when they say the first sequence looks more significant than the latter. It's the same thing as when statisticians deride people for choosing 010010 as the "more random" sequence than 000000; if each element is independently determined, then any single outcome is as likely as another, but if one is instead taking a more intuitive, "homogenous/nonhomogenous" approach then indeed, you'd expect more truly randomly generated sequences to "look like" the first one than the second. --Fastfission 18:14, 6 September 2006 (UTC)

I remember hearing that certain conditions could lead to men having more girls than boys. I think it was high levels of testosterone, which can also lead to early baldness. I don't have a source for this though, but I'm sure Karl Kruszelnicki mentioned the link once. If anyone has better info it'd be appreciated. I should probably check the articles mentioned too. —Pengo ^{talk · contribs} 11:47, 6 September 2006 (UTC)

The sex ratio article links to a couple articles about research that indicate that men infected with Hepatitis B have more male children. There was also some recent press about a study that showed that attractive people were more likely to have female children and some articles mentioned previous studies by Satoshi Kanazawa that showed that scientists, mathematicians engineers, big or tall parents and violent fathers are all more likely to have sons than daughters. It seems pretty certain to me that all couples do not have the exact same 50-50 chance of boy and girl children. -- Plutortalkcontribs 13:02, 6 September 2006 (UTC)

It's not a 50-50 chance, even on the average. More boys are born than girls. --Trovatore 21:10, 6 September 2006 (UTC)

Note however, that the the ratio of sexes born need not be the same as the ratio of sexes conceived. The sex of a foetus will be determined at conception, however, during the 9 months in utero, there could well be differences in survival rates between sexes. There could also be genetic predispositions to bearing children of one sex over the other, theoretically at least. For example, consider a mother who has an allele on one of the X-chromosomes that, when hemizygous would cause early embryonic lethality by haploinsufficiency (lets ignore the problems that Lyonisation would cause her or her female children, for the moment). All else being equal, every child born to her would have a 1/3 probability of being male, rather than a 1/2. However, the probability of her conceiving a child of either sex remains 1/2, respectively. I am not familiar with an exact gene that this model would fit this example, but i'll wager it happens. Thus having multiple children of the same sex is most often simply due to chance, but i would argue that a specific genetic predispositions cannot be ruled out. Rockpocket 01:12, 7 September 2006 (UTC)

I think you're wrong about the probability of conception for either sex being 1/2. If I recall correctly, male fetuses are more likely to die before birth, so the disparity at time of conception must be even larger than the disparity at time of birth. Of course, that could be rolled into your "other things being equal", but my point is that other things are not equal. --Trovatore 03:50, 7 September 2006 (UTC)

Possibly true. However, the problem with the data you mention, is that it is based on later-pregnancy miscarriages. As much as 50% of all conceptions fail: its thought that around 1/4 of fertilized eggs fail to implant in the uterine wall and 1/3 are spontaneously aborted within the first six weeks after conception, both without the mother ever knowing she is pregnant. Since we have no idea of the sex ratio of these failures, the impact of the (relatively speaking) small number of later-stage male-biased miscarriages could be negligible. If these early failures balanced up the sex bias, your logic would fail. My assumption of equality was to demonstrate my theoretical point on the difference between conception/birth ratios in a simplified model. The fact is, we simply don't know if "other things are equal", as we don't have a full data set. Rockpocket 05:40, 7 September 2006 (UTC)

I think that's a stretch, frankly. The ratio of Y-carrying androsperm to X-carrying gynosperm is known, and the ratios of later fetuses is known, and both (unless I'm misinformed) support the idea that there are more male conceptions. I think you're overapplying the notoriously shaky principle of indifference. --Trovatore 07:33, 7 September 2006 (UTC)

I completely agree. Per Occam's razor, that certainly is the post parsimonious explanation. However, the possibility remains, however remote... Rockpocket 18:20, 7 September 2006 (UTC)

Sleep

Why do I get a headache if I'm fortunate enough to get too much sleep? And is this a common reaction to sleeping too much? Dismas|^(talk) 10:32, 6 September 2006 (UTC)

It's a known phenomenon. This article discusses a possible mechanism. --Lambiam^Talk 10:49, 6 September 2006 (UTC)

How much is too much, because I can't say I've ever had a headache from this. --liquidGhoul 11:00, 6 September 2006 (UTC)

I find it usually happens when I go to sleep again, i.e. when I half-wake up, decide that I don't want to get up at this time today, and wake up again a few hours later with a headache.  freshofftheufoΓΛĿЌ  14:03, 7 September 2006 (UTC)

Actually that article doesn't say much. It can be many things, including but not limited to:

1. Musculoskeletal discomfort due to prolonged immobility, imperfect bedding, or uncomfortable position;
2. Overheating;
3. Mild dehydration;
4. Low blood sugar;
5. Caffeine withdrawal;
6. Low blood pressure;
7. Poor sinus drainage (exacerbated by being prone);
8. Sleep apnea. Oxygen deprivation causes headaches, and the longer you're experiencing it, the worse a headache you'll get.

--Anchoress 11:09, 6 September 2006 (UTC)

Sn1&Sn2 Reactions

please tell me about following things in sn1 & sn2 reactions

1.Nature of substract
2.Nature of attacking nueclophile
3.Nature of leaving ion
4.Nature of solvent

It would probably be best if you look at SN1 reaction and SN2 reaction then come back with any specific questions you still have.--Ed (Edgar181) 13:59, 6 September 2006 (UTC)

A car for $1

What would you do if you see an ad like this:

• Offer for sale of EXACTLY ONE $30,000 car for $1.
• First come first served.
• However, you're required to throw a die:
  • If the 1st one in line gets a "1"; he/she takes the car home.
  • If the 2nd one in line gets a "1" or "2"; he/she takes the car home.
  • If the 3rd one in line gets a "1", "2" or "3"; he/she takes the car home. ...
  • Whatever 6th one in line gets; he/she takes the car home if all previous five did not make it.

If you want that car, what is your strategy to maximize your likelihood of winning? -- Toytoy 13:59, 6 September 2006 (UTC)

Just work out the probabilities. The first guy has a 1/6 chance of winning a roll, and a guaranteed chance to roll. The next has a 2/6 chance of winning if he rolls, but only a 5/6 chance of getting to roll. The calculations proceed thusly. — Lomn | Talk 14:17, 6 September 2006 (UTC)

I should note: a more interesting question is "what is a fair price for the chance to win the car?" Obviously the seller can't recoup his $30000 with $1 tickets, but if the tickets are only bought when the die is rolled (rather than in advance), what should he charge to average $30000 worth of tickets sold? — Lomn | Talk 14:21, 6 September 2006 (UTC)

Require 100 sided dice, then be last in line.

Hire some gorillas to prevent anyone else from queueing. So long as the hired help costs less than $29,994, you'll walk away smiling. --Dweller 14:28, 6 September 2006 (UTC)

Go 2nd or 3rd, it doesn't matter which.

Person I	Chance of rolling I	Chance of winning roll I	Odds of getting car I
1	1.00	0.17	0.17
2	0.83	0.33	0.28
3	0.56	0.50	0.28
4	0.28	0.67	0.19
5	0.09	0.83	0.08
6	0.02	1.00	0.02

- Nunh-huh 20:26, 6 September 2006 (UTC)

It might be an intersting game theory problem if you had a group of 6 people who each had to volunteer to go first, second, third etc. You'd have to set up the mechanism for volunteering in some specific way, but it might be interesting. --best, kevin [kzollman][talk] 21:43, 6 September 2006 (UTC)

If I saw this ad, and was able to determine it was not a marketing promotion, I would ignore it as a probable scam of some type, simply because common sense says that reasonable people don't just give away expensive cars. --Ginkgo100 ^{talk · e@} 21:50, 6 September 2006 (UTC)

Yea, like you may only be able to get the car for $1 if you agree to pay $40,000 for the car keys. :-) StuRat 23:35, 6 September 2006 (UTC)

If the car is legally yours, I'm pretty sure you could get new keys made (or the locks replaced) for less than $40,000. (In fact, you could probably get new keys to a car for less than $40,000 even if it wasn't legally yours, but that could cause other kinds of problems further down the line...) —Ilmari Karonen (talk) 01:26, 7 September 2006 (UTC)

I'm saying that the car wouldn't be legally yours (they wouldn't sign over the title) until you bought the $40,000 key, hence the trick. StuRat 06:36, 7 September 2006 (UTC)

I actually saw an ad once for a hideously expensive bicycle, that cost like a car, and you got a car with it. :-) —Bromskloss 13:54, 7 September 2006 (UTC)

BTW, this question should have been posted to the Math Ref Desk. StuRat 23:37, 6 September 2006 (UTC)

I'd buy all six tickets for $1 each, that's still just $6 for a $30000 car. – b_jonas 08:53, 7 September 2006 (UTC)

That answer sounds strangely familiar. --Dweller 09:40, 7 September 2006 (UTC)

yDNA Mutation Rates

What are the relative Mutation Rates of yDNA STR's used in Genetic Genealogy?......... Cymri

there are no good reliable published figures for those differential rates. The closest you'll get is a statement that a given STR is a "slow" (or "fast") mutater. - Nunh-huh 20:02, 6 September 2006 (UTC)

Ok Can anyone list the "fast" and "slow" Loci? or perhaps provide a limk to such information. cymri

Recognize this optimization problem?

I need to find a search algorithm for the following optimization problem. We are given $N$ (smallish) finite sets $A_{k}$, and we are to choose one element from each, to yield a multiset $B$ of size $N$. We are also given a finite mapping $\omega$ from multisets to real-valued weights, and we are to maximize the sum of the weights associated with the submultisets of $B$, $\sum _{C\subseteq B}\omega _{C}$.

If we constrain the domain of $\omega$ to multisets of size $1$, we can choose from each $A_{k}$ independently, and the problem is trivial.

If necessary, I can afford to constrain the domain of $\omega$ to multisets of size $2$, but I'm beginning to suspect that this is already NP-complete.

If it is NP-complete then I would appreciate any advice on approximations or reductions to other problems for which good solvers are available. Can I do better than the obvious reductions to ILP or weighted MAX-SAT?

Thanks and best wishes 128.220.220.95 19:20, 6 September 2006 (UTC)

I suggest you move this to the Mathematics reference desk. --Lambiam^Talk 23:02, 6 September 2006 (UTC)

Good point. I will start there next time. 128.220.220.95 17:00, 8 September 2006 (UTC)

If we allow $\omega _{C}\not =0\;\forall \left|C\right|\leq 3$, this problem would solve boolean satisfiability (in particular 3SAT), as you hinted with MAX-SAT. Consider $A_{k}=\{(k,0),(k,1)\}$; then, for each value $(k,i)$ in a disjunction (that is, $(k,0)$ if $\lnot x_{k}$ appears, and $(k,1)$ if $x_{k}$ appears), increment $\omega _{\{(k,i)\}}$. Then undo the double counting (where $(\lnot )x_{k}$ and $(\lnot )x_{k'}$ succeed in a term containing both anyway) by decrementing $\omega _{\{(k,i),(k',i')\}}$ for each pair of literals that appear in the same disjunction. Then repair three successes minus three handshakes by incrementing $\omega _{\{(k,i),(k',i'),(k'',i'')\}}$. Then maximize, and see if the result has value equal to the number of disjunctions (this can be done in polynomial time because there are no more than ${N \choose 1}+{N \choose 2}+{N \choose 3}\in O(N^{3})$ non-zero values of $\omega _{C}$). This reduction typically involves negative weights, which you might not have had in mind, but I imagine that it could be recast without them. Obviously the corresponding argument with $\left|C\right|\leq 2$ fails because it's 2SAT then, so I'm afraid I don't have any truly useful answer at the moment. Hope this helps. --Tardis 23:20, 6 September 2006 (UTC)

Very cool, and I believe I've just learned something from the 2-satisfiability article that allows me to finish your argument: 2-SAT can be done in polynomial time, but MAX-2-SAT is NP-complete. It looks like I'm back to the drawing board, so thanks for helping me figure that out sooner rather than later. 128.220.220.95 17:00, 8 September 2006 (UTC)

Dogs and people

I know that any answer to this question must remain as speculation: What do dogs think humans are? They must not think of us as fellow dogs, because we probably smell different, and they do not try to mate with us. Are they usually submissive because we appear to be much larger members of some other species? Does Wikipedia have any articles on this subject? Pete

There is a lot of debate over exactly how dog/human relations are or ought to be (i.e. does the human master represent the alpha pack member?), but I think one can say somewhat safely that most animals are not able to get into the sorts of relationships that dogs have with humans (even cats seem to have difficulty tolerating humans a lot of the time, much less non-pet animals), and it is precisely this character trait which has made dogs "man's best friend" as they say. For whatever reason they seem to be able to adapt to co-habilitation with humans very well, and many dogs seem to exhibit symptoms of real affection for their human owners (one can always wonder if it is a trick, but I'm pretty sure my dog likes me—she goes way above and beyond what would be necessary to get food and attention). Of course dog behavior towards humans can vary a lot with breed—some breeds are notoriously independent and stubborn, some are very easy to train, some are known to be very friendly towards people, and some are known for their ability to be quite violent to humans. Unfortunately we don't seem to have a lot on this (our Behavior subsection of the "Dog" article is really, really short). We have a short article on Companion dogs but it doesn't have much on dog psychology. --Fastfission 20:31, 6 September 2006 (UTC)

I'm not sure its proper to attribute the sort of cognitive abilities to dogs that allow them to classify us. Perhaps dogs don't classify animals in their environments in the same way humans do. It might not "occur" to a dog to ever think about what we are. I don't know much about research into animal cognition, but I'm not sure if there is any reason to think they classify their environment into species. --best, kevin [kzollman][talk] 21:40, 6 September 2006 (UTC)

Just a couple of things to add. Many dogs actually do try to "mate" with us, or at least our legs. As for being submissive to larger creatures, it may be counterintuitive but the truth is that the larger the dog, the more gentle and submissive it is. It tends to be those tiny rat-dogs, the Chihuahuas, the Toy Poodles etc. that tend to be the nastiest and the most anti-social towards many humans. Have you ever been growled or been given dirty looks by a giant St. Bernard or Golden Retriever? Loomis 21:47, 6 September 2006 (UTC)

I took care of a toy poodle (absolutely tiny) for a neighbor for a few days. He didn't seem to like me much, especially if he was on the ground and I was upright. He also tried to kill the vaccuum. However he was very mellow around most members of the household, he was usually very happy to just sit with/on you. Perhaps he was unusually well-trained, but he adapted very quickly to the change. 206.124.138.153 05:42, 9 September 2006 (UTC)

Based on my (limited) observations of dogs, individual dogs behave in a somewhat consistently different way with respect to members of different species: they don't greet cats like they greet dogs, and a dog that chases one unknown cat tends to chase them all. Yet the same dog will not chase humans, only bark at them. To the extent that it is reasonable to apply human labelling to what dogs "think", my best guess is that dogs think that dogs are dogs, cats are cats, and humans are humans. --Lambiam^Talk 23:12, 6 September 2006 (UTC)

We do have two relevant articles -- Animal cognition and Dog intelligence. --Halcatalyst 23:21, 6 September 2006 (UTC)

I go with dogs viewing their owner as the pack leader/alpha dog, whereas cats view their owner as their mother (even male owners). StuRat 23:20, 6 September 2006 (UTC)

This article from the NYT has something about the problems created by framing the interaction with your dog in the alpha dog theory. Dogs are not wolves, but also for a pack of wolves the social structure is not like that of a troop of chimps. --Lambiam^Talk 04:09, 7 September 2006 (UTC)

I believe that dogs and wolves are, in fact, one species. This means they can mate and produce fertile offspring. StuRat 02:05, 9 September 2006 (UTC)

Supporting that thought... the best way to completely immobilize a cat is to pick it up by the scruff of its neck, like the mother cat does. --Halcatalyst 23:23, 6 September 2006 (UTC)

The immobilization reflex is mechanical and has nothing to do with how the cat views us. --Lambiam^Talk 04:09, 7 September 2006 (UTC)

Behaviourists from John B. Watson to B.F. Skinner saw no need to postulate what animals or people thought. Instead they saw our actions as the result of behavioural conditioning. The question of what a dog thinks a person is would be as meaningless as the question of what a person thinks a dog is (toy? child substitute?). They might note behaviours such as a cat kneading the owner stomach as learned from the utility of that conditioned response in obtaining milk from the mother. Cognitive psychologists theorize about internal mental states and how they control behaviour.

Many dog owners would say that dogs seem to think they and people are not that different, whether it be two kinds of dog or two kinds of people. Edison 23:40, 6 September 2006 (UTC)

Hmm. Sounds like a classical case of psychological projection to me. --Lambiam^Talk 04:13, 7 September 2006 (UTC)

I thought if the dogs were bigger, the more agressive and less social they were. ._. --Proficient 04:18, 7 September 2006 (UTC)

St. Bernards are quite large, but they're highly social as well as gentle. Behavioural traits aren't necessarily tied to the size at all; I've seen small dogs that are insanely aggressive. -- Consumed Crustacean (talk) 04:25, 7 September 2006 (UTC)

I believe the counterintuitive result that small dogs are more aggressive is due to artificial selection. While an aggressive small dog is considered by some to be acceptable, or even cute, an aggressive large dog is seen as dangerous. Thus, aggressive large dogs were less wanted and less likely to be bred than aggressive small dogs. After a few thousand generations, this leads to a lack of aggressive, large dog breeds. StuRat 04:29, 7 September 2006 (UTC)

That is entirely possible. Behaviour doesn't occur in a vacuum, however, and another factor is fear. Most animals will display aggressive behaviour when they feel threatened or harrassed - the fight part of fight or flight. The size of a dog in relation to the threatening cue is a factor in where they feel threatened or not, hence small dogs may be more likely to be aggressive than large ones, simply because they are more afraid. Genetics play a role in this too, of course. Note that we have bred larger dogs to be working dogs. Having them afraid of, or aggressive with, humans is not an ideal characteristic for their function. So that has been selected against. On the other hand, small show dogs are bred for how they look, so their fear of humans (as StuRat suggests) is inconsequential for their function. Rockpocket 06:00, 7 September 2006 (UTC)

William Gray (Meteorologist)

I have searched all over the internet for some background information on William Gray the hurricane forecastor and am unable to find out his birth date, where he was born and general information on his childhood. I did find ample information on the work he has done in hurricane forecasting but would be very gratefull if someone could help me on his background.

regards,

mactennis.

A recent article[2] says he's 76. That narrows his birth down, so you can try more searches to pinpoint it. Melchoir 21:06, 6 September 2006 (UTC)

Trying to get glasses

Three years ago I failed my school's eye exam and since then I have been to the eye doctor three times. Each time, the doctor told me that I was really close to needing glasses but my perscription is so small it would not even be worth it. Is there anything I can do to tip the scales in favor of requiring glasses within the year? Advice would be appreciated.

Usually I respond to people who are honest. Just say - "it may be a small correction, but it really means a lot to me. Could you please prescribe me glasses so I can use them when I feel I need to?" If they will not sell you glasses, ask for your refractive error. If all else fails, see a different doctor! InvictaHOG 01:28, 7 September 2006 (UTC)

Watch television up close, read in the dark, and neglect your carrot consumption. Staring at wikipedia pages all day will probably help too. AEuSoes1 02:20, 7 September 2006 (UTC)

I think I once read that reading in the dark doesn't hurt your eyesight, but that might have been a myth. --Proficient 04:20, 7 September 2006 (UTC)

Yeah, I don't see how it would. Carrots also don't help with eyesight. I was being facetiously misleading. AEuSoes1 05:31, 7 September 2006 (UTC)

How often do you masturbate, any room for improvement? Some people continue to believe that "self abuse" leads to deterioration of eyesight. That is almost universally dismissed by doctors as untrue, of course, but what have you got to lose ;)? In all seriousness, it is inadvisable to try any technique to make your eyesight worse. Anything the might work would also run the risk of damaging your eyes. Your optometrist is most likely delaying the inevitable out of a misplaced concern that you might not wish to have specs. as InvictaHOG suggested, I would recommend explaining honestly and firmly that you would like to have your vision corrected and would appreciate if they could do that for you. If they can't, take your future business elsewhere. Rockpocket 06:44, 7 September 2006 (UTC)

You obviously think you need glasses, but why? If you are having difficulty in reading small print, pick up some cheap reading glasses at a drug store/chemist.--Shantavira 07:16, 7 September 2006 (UTC)

• The doctor said the prescription was too small to require correction. Have you ever asked him what the values where. If it was anything up to 0.5 of correction, he is probably correct about you not needing correction. By the way, the fact you go to the eye doctor once a year (or at least three times in three years) is something you should continue. Having your eyes checked should be something as regular as having your teeth checked. - Mgm|^(talk) 07:28, 7 September 2006 (UTC)

I was like this, aged about 10. I thought that wearing glasses would improve my appearance(!) (Sigh) I even pretended in sight examinations that I couldn't read very small letters on the sight chart that I actually could read. I was therefore prescribed glasses of the wrong prescription, before I needed them. I've been wearing glasses ever since and now can't cope without them. The deterioration of my sight is probably mostly down to nature, but in an ignorant lay manner, my gut instinct is to attribute some of the blame to this stupid behaviour. So, my advice (as an ignorant lay person)?

• 1. Don't contemplate pretending your sight is worse than it is
  2. Avoid wearing prescription lenses for as long as you can, within the sensible advice of your optometrist
  3. Don't pick up "cheap reading glasses" that haven't been prescribed for you if you're young enough that "three years ago" you were still at school
  4. Glasses don't make you look clever or glamorous or alluring or mysterious. If you're tempted, think Clark Kent v Superman.
  5. Don't do stupid things that you'll regret later in life.heck, that's what being young is all about, isn't it? Anyway, I ain't young and I do really stupid things all the time--Dweller 10:00, 7 September 2006 (UTC)

Or just buy glasses that have no refraction index?  freshofftheufoΓΛĿЌ  13:52, 7 September 2006 (UTC)

Im puzzled that the school eye exam says you need glasses when a professional optometrist says you dont. I know whom I would believe (the pro)--Light current 14:48, 7 September 2006 (UTC)

For me the only real "pro" is the patient. If you have trouble seeing, you need glasses. It doesn't matter how "weak" your prescription would be. I wear glasses with such a weak prescription (-.50 left, -.75 right) that when my friends try them on for fun they just look like clear glass to them and they find it hard to understand what I need them for. Yet for me the difference is HUGE. Without them everything is fuzzy and with them everything is crystal clear.

As for buying cheap glasses at a drugstore, there are a whole bunch of reasons not to, but by far one of the most important is the fact that these places only tend to sell glasses to correct for presbyopia or "far-sightedness". Since I'm assuming you're rather young (being in school and all), I'm assuming that like me, you've got the opposite: myopia or "near-sightedness". Presbyopia tends to happen to practically everybody as they age. When older people start to have trouble reading small print, they get reading glasses. These are the types that are sold in drugstores. They always have "plus" prescriptions (as in +1, +2, +2.5 etc...designed for presbyopia) and also, they always assume both eyes are in equal condition. You'll never find a pair that are, for example, +2 right, +3 left. My guess is that you're like me and you're not presbyopic at all, but rather slightly myopic. That means that your glasses would have to have a "minus" prescription. It's easy to tell the difference. If you don't have any trouble with "up-close" things like reading, but have a lot of trouble seeing things that are further away, like the tv or or the blackboard or recognizing a friend from across the street, that means you're myopic, and besides being bad for you, those drugstore glasses wouldn't even be of any help...if you wore them they'd probably make things even fuzzier.

In any case, go to your eye doctor, and just be firm about it. Tell him or her that you can't see well, (and, if true, throwing in a bit about how you have trouble reading the blackboard would definitely help, nobody wants to have students who can't read the blackboard because they have a stupid doctor!) and that you NEED glasses. If s/he doesn't cooperate, see another doctor. If that doesn't work, talk to the folks at school where you failed the eye tests, I'm sure they'd be a lot more sympathetic. Good luck! Loomis 23:28, 8 September 2006 (UTC)

OK Let me put this another way. Why is there such a difference in the school eye exam and the optometrists results? Can this minor correction really be necessary for children, when it obviously isnt for adults?--Light current 18:03, 9 September 2006 (UTC)

When I was 10 years old, I was told I'd need glasses when I came to start driving. At 17, I went, and was told my eyesight was practically perfect - but since they were free on the NHS, she would still prescribe the -.25 my left eye could use (seriously, one eye being .25 out is the minimum wrong that they're capable of detecting). If you're having trouble seeing, and need it corrected, try for a second opinion. If you've just been told by someone that you'll need them in the future, see if time sorts it out. There's certainly absolutely nothing to be gained by purposefully damaging your vision. If you're desperate to start wearing glasses, you could pay for some with flat glass in both eyes, but if people ask you why you're wearing them, that could be an interesting conversation. --Mnemeson 23:50, 9 September 2006 (UTC)