user4748: I am a relatively new (about four months) meditator. 
My meditation technique is closing my eyes and focusing on the sensation of the breath as it passes in and out of my throat. Today I was meditating for 30 minutes and, as often happens, I saw swirling lights in the darkness of my closed eyes. 
As I became more deeply focused on the breath-sensation, the lights went away and there was darkness, but the odd thing was that the darkness extended - it seemed as though I was looking down an endless, dark hallway rather than just looking at my eyelids. 
As I noted this, I started to see a purple, vibrating orb appear. I remember thinking to myself that maybe I was about to have some kind of mystical experience. I became a little excited about this, but all of a sudden the excitement morphed into an incredible fear. My breath began to come in gasps and was shaky, and my heart was pounding. I eventually managed to calm down, but wow that was strange. 
So my question is - has this happened to anyone else, and is there a reasonable explanation? I have always had issues with anxiety, so I wonder if that is related to this experience.
I have heard that meditation can be harmful - is this a sign that I should refrain from meditating?
Thanks for taking the time to read.
Ian

user3551: My meditation technique is that of closing my eyes and focusing on the sensation of the breath as it passes in and out of my throat.
What kind of meditation are you doing.Samatha or vippassana?If it's samatha just keep focusing on the physical sensation of the breath.If it's vippassanna just keep noting.
I saw swirling lights in the darkness of my closed eyes. As I became more deeply focused on the breath-sensation, the lights went away and there was darkness, but the odd thing was that the darkness extended- it seemed as though I was looking down an endless, dark hallway rather than just looking at my eyelids.
You may be seeing Phosphenes since you mentioned looking at your eye lids.Also your not supposed to be looking at your eyelids your supposed to be focused on the breath.
As I noted this, I started to see a purple, vibrating orb appear.
This could be the nimitta.But nimitta arising is one thing and leading to a mystical experience which i assume is the jhanas is another thing.Nimittas become quite common when you sit everyday.Sometimes they appear and dissapear when you start breathing.This kind of nimitta is as useless as phosphenes.Don't shift your focus from the breath to the nimitta.In other words.don't try to look at it.It will disappear and appear at another point and you'll spend the rest of the meditation playing tag.
I remember thinking to myself that maybe I was about to have some kind of mystical experience.
If you would like to experience this "mystical experience" ignore the nimitta.The more you ignore the better.Keep your focus on the breath.The nimitta will break into your awareness on it own and merge with the breath,or specifically the point where the physical sensation of the breath is felt.
I became a little excited about this, but all of a sudden the excitement morphed into an incredible fear. 
Excitement and fear is a hindrance.I think it comes from being afraid of the unknown.I suggest reading the suttas or learning the proper meditation techniques so you develop confidence or faith in the practice.
I have heard that meditation can be harmful- is this a sign that I should refrain from meditating?
I don't think meditation is harmful.i think our minds are harmful.Meditation is only a tool to clear away the things we store in our minds,to make conscious the subconscious.

user2495: What you experience during your practice is absolutely not harmful. It is a stage in the meditation process. More: it is a sign that you proceed in the right direction.
The vibrating 'light' that arises and passes away is the so-called nimitta.
Catherine, Shaila, (2008) Focused and Fearless. A Meditator’s Guide to States of Deep Joy, Calm, and Clarity p. 116:

‘The breath nimitta usually appears as a stable, smooth, white radiance associated with the focus on the breath. It is a mental reflection of the breath and includes no physical aspect; the light and breath may appear to have merged into a single mental experience of breath.’

Dalai Lama & Chodron, Thubten, (2014), Buddhism. One Teacher, Many Traditions p. 88:

‘The learning sign [nimitta] is an image arisen from this physical sensation [the sensation of the breath at the nostrils and upper lip, as it enters and exits]. When it arises, the meditator turns her attention to the nimitta—a colored luminous sphere or a radiant light—and that becomes his object of meditation [i.c. the arising and passing away of this nimitta].’

Brahm, Ajahn, (2011) The Art of Disappearing. The Buddha’s Path to Lasting Joy p. 120-121:

‘If you haven’t experienced these things, it can all sound like fantasy. But as your meditation improves, you gradually start to realize that this is not fantasy, that these states do exist, and what I’m saying is valid.
All you need to do is take your meditation further and drop more of
  the body. As you practice in this way, you start to bliss out. You
  understand that the body isn’t just suffering because of old age,
  sickness and death, but even its normal state is a huge heap of
  suffering. This is one of the incredible powerful realizations you get
  from deep meditation. A nimitta is enough to give you this
  realization, but if you get into jhana it’s unmistakably clear.’


user4750: When in meditation, you will pass through different psychic experiences. Here are some points:

I would suggest trying meditating on a chair so that your feet are on the ground. If you feel panic or excitement rising, feel the soles of your feet. This will help you get grounded.
Feel the sensation on different parts of your body. Learn to rest in the sensation of your body.
You might try to combine meditation with a physical excercise (qigong, jogging, you name it)
Don't get excited by psychic experiences. Panic and extreme excitement are the different sides of the same coin. Never search for psychic experiences.
Remember you are free at any time to open your eyes and look around to make sure you are safe and not under any physical threat.
I wouldn't watch horror movies or do other things that flirt with the fear in the psyche.
If the panic strikes, endeavour to get back in the stillness of your own sensation. Remember that these energies are all appearances. They are not real in a physical sense so they cannot really harm you.


user-1: welcome!
Generally, from Buddhism standpoint, meditation is not practiced for the sake of mystical experiences. In vipassana exercises, whatever sensation is felt, it's supposed to be observed, we are not supposed to be overwhelmed by it. In general, arbitrary sensations and imaginations are not to be stimulated. And as importantly, awareness should be constant: when one embarks in sensations and imaginations, awareness is lost. 
If awareness is lost, whatever imagination inside your mind becomes powerful, your forget that you're safe, sitting comfortably, and believe you are in danger, when nothing will really happen.
I remember reading an account of a meditator who described having visions during meditation, and later on, seeing his visions were true. He brought this to his teacher who told him to not be distracted by such small thing. That's a valuable attitude to have during meditation. At least if one is aiming for the higher goals.
In general also, if the meditator is not calm (if he is excited, in fear, tired, etc), meditation is impaired:

But with excessive thinking and pondering I might tire my body, and when the body is tired, the mind becomes strained, and when the mind is strained, it is far from concentration. So I steadied my mind internally, quieted it, brought it to singleness, and concentrated it. Why is that? So my mind should not be strained.
-- Dvedhāvitakka Sutta [Bodhi trans.], MN 19

So, to answer your questions:

This is relatively common, specially when our minds follow patterns that easily lead to strong sensations. A remedy for this is having a very good understanding of the practice (for example, understanding very well the five hindrances)
A lot of things can be harmful if not done properly. Though meditation doesn't seem to require knowing much, it can be very hard to do it without study.

From here, I suggest having a good understanding of primordial sources for this practice: the Satippathana Sutta and the Anapanasati Sutta where the Buddha explains their techniques. I also strongly suggest looking for books that cover detailed explanation for these. Finally, there are a lot of questions regarding meditation here, I suggest looking up for those as well.

4748: <p>I am a relatively new (about four months) meditator. </p>

<p>My meditation technique is closing my eyes and focusing on the sensation of the breath as it passes in and out of my throat. Today I was meditating for 30 minutes and, as often happens, I saw swirling lights in the darkness of my closed eyes. </p>

<p>As I became more deeply focused on the breath-sensation, the lights went away and there was darkness, but the odd thing was that the darkness extended - it seemed as though I was looking down an endless, dark hallway rather than just looking at my eyelids. </p>

<p>As I noted this, I started to see a purple, vibrating orb appear. I remember thinking to myself that maybe I was about to have some kind of mystical experience. I became a little excited about this, but all of a sudden the excitement morphed into an incredible fear. My breath began to come in gasps and was shaky, and my heart was pounding. I eventually managed to calm down, but wow that was strange. </p>

<p>So my question is - has this happened to anyone else, and is there a reasonable explanation? I have always had issues with anxiety, so I wonder if that is related to this experience.</p>

<p>I have heard that meditation can be harmful - is this a sign that I should refrain from meditating?</p>

<p>Thanks for taking the time to read.
Ian</p>
 3551: <p><strong>My meditation technique is that of closing my eyes and focusing on the sensation of the breath as it passes in and out of my throat</strong>.</p>

<p>What kind of meditation are you doing.Samatha or vippassana?If it's samatha just keep focusing on the physical sensation of the breath.If it's vippassanna just keep noting.</p>

<p><strong>I saw swirling lights in the darkness of my closed eyes. As I became more deeply focused on the breath-sensation, the lights went away and there was darkness, but the odd thing was that the darkness extended- it seemed as though I was looking down an endless, dark hallway rather than just looking at my eyelids</strong>.</p>

<p>You may be seeing <a href="http://en.wikipedia.org/wiki/Phosphene" rel="nofollow">Phosphenes</a> since you mentioned looking at your eye lids.Also your not supposed to be looking at your eyelids your supposed to be focused on the breath.</p>

<p><strong>As I noted this, I started to see a purple, vibrating orb appear</strong>.</p>

<p>This could be the nimitta.But nimitta arising is one thing and leading to a mystical experience which i assume is the jhanas is another thing.Nimittas become quite common when you sit everyday.Sometimes they appear and dissapear when you start breathing.This kind of nimitta is as useless as phosphenes.Don't shift your focus from the breath to the nimitta.In other words.don't try to look at it.It will disappear and appear at another point and you'll spend the rest of the meditation playing tag.</p>

<p><strong>I remember thinking to myself that maybe I was about to have some kind of mystical experience</strong>.</p>

<p>If you would like to experience this "mystical experience" ignore the nimitta.The more you ignore the better.Keep your focus on the breath.The nimitta will break into your awareness on it own and merge with the breath,or specifically the point where the physical sensation of the breath is felt.</p>

<p><strong>I became a little excited about this, but all of a sudden the excitement morphed into an incredible fear</strong>. </p>

<p>Excitement and fear is a hindrance.I think it comes from being afraid of the unknown.I suggest reading the suttas or learning the proper meditation techniques so you develop confidence or faith in the practice.</p>

<p><strong>I have heard that meditation can be harmful- is this a sign that I should refrain from meditating</strong>?</p>

<p>I don't think meditation is harmful.i think our minds are harmful.Meditation is only a tool to clear away the things we store in our minds,to make conscious the subconscious.</p>
 2495: <p>What you experience during your practice is absolutely not harmful. It is a stage in the meditation process. More: it is a sign that you proceed in the right direction.</p>

<p>The vibrating 'light' that arises and passes away is the so-called <strong><em>nimitta</em></strong>.</p>

<p><em>Catherine, Shaila, (2008) Focused and Fearless. A Meditator’s Guide to States of Deep Joy, Calm, and Clarity p. 116:</em></p>

<blockquote>
  <p>‘The breath nimitta usually appears as a stable, smooth, white radiance associated with the focus on the breath. It is a mental reflection of the breath and includes no physical aspect; the light and breath may appear to have merged into a single mental experience of breath.’</p>
</blockquote>

<p><em>Dalai Lama &amp; Chodron, Thubten, (2014), Buddhism. One Teacher, Many Traditions p. 88:</em></p>

<blockquote>
  <p>‘The learning sign [nimitta] is an image arisen from this physical sensation [the sensation of the breath at the nostrils and upper lip, as it enters and exits]. When it arises, the meditator turns her attention to the nimitta—a colored luminous sphere or a radiant light—and that becomes his object of meditation [i.c. the arising and passing away of this nimitta].’</p>
</blockquote>

<p><em>Brahm, Ajahn, (2011) The Art of Disappearing. The Buddha’s Path to Lasting Joy p. 120-121:</em></p>

<blockquote>
  <p>‘If you haven’t experienced these things, it can all sound like fantasy. But as your meditation improves, you gradually start to realize that this is not fantasy, that these states do exist, and what I’m saying is valid.</p>
  
  <p>All you need to do is take your meditation further and drop more of
  the body. As you practice in this way, you start to bliss out. You
  understand that the body isn’t just suffering because of old age,
  sickness and death, but even its normal state is a huge heap of
  suffering. This is one of the incredible powerful realizations you get
  from deep meditation. A nimitta is enough to give you this
  realization, but if you get into jhana it’s unmistakably clear.’</p>
</blockquote>
 4750: <p>When in meditation, you will pass through different psychic experiences. Here are some points:</p>

<ul>
<li>I would suggest trying meditating on a chair so that your feet are on the ground. If you feel panic or excitement rising, feel the soles of your feet. This will help you get grounded.</li>
<li>Feel the sensation on different parts of your body. Learn to rest in the sensation of your body.</li>
<li>You might try to combine meditation with a physical excercise (qigong, jogging, you name it)</li>
<li>Don't get excited by psychic experiences. Panic and extreme excitement are the different sides of the same coin. Never search for psychic experiences.</li>
<li>Remember you are free at any time to open your eyes and look around to make sure you are safe and not under any physical threat.</li>
<li>I wouldn't watch horror movies or do other things that flirt with the fear in the psyche.</li>
<li>If the panic strikes, endeavour to get back in the stillness of your own sensation. Remember that these energies are all appearances. They are not real in a physical sense so they cannot really harm you.</li>
</ul>
 -1: <p>welcome!</p>

<p>Generally, from Buddhism standpoint, meditation is not practiced for the sake of mystical experiences. In vipassana exercises, whatever sensation is felt, it's supposed to be observed, we are not supposed to be overwhelmed by it. In general, arbitrary sensations and imaginations are not to be stimulated. And as importantly, awareness should be constant: when one embarks in sensations and imaginations, awareness is lost. </p>

<p>If awareness is lost, whatever imagination inside your mind becomes powerful, your forget that you're safe, sitting comfortably, and believe you are in danger, when nothing will really happen.</p>

<p>I remember reading an account of a meditator who described having visions during meditation, and later on, seeing his visions were true. He brought this to his teacher who told him to not be distracted by such small thing. That's a valuable attitude to have during meditation. At least if one is aiming for the higher goals.</p>

<p>In general also, if the meditator is not calm (if he is excited, in fear, tired, etc), meditation is impaired:</p>

<blockquote>
  <p>But with excessive thinking and pondering I might tire my body, and when the body is tired, the mind becomes strained, and when the mind is strained, it is far from concentration. So I steadied my mind internally, quieted it, brought it to singleness, and concentrated it. Why is that? So my mind should not be strained.</p>
  
  <p>-- Dvedhāvitakka Sutta [Bodhi trans.], MN 19</p>
</blockquote>

<p>So, to answer your questions:</p>

<ul>
<li>This is relatively common, specially when our minds follow patterns that easily lead to strong sensations. A remedy for this is having a very good understanding of the practice (for example, understanding very well the <a href="http://en.wikipedia.org/wiki/Five_hindrances">five hindrances</a>)</li>
<li>A lot of things can be harmful if not done properly. Though meditation doesn't seem to require knowing much, it can be very hard to do it without study.</li>
</ul>

<p>From here, I suggest having a good understanding of primordial sources for this practice: the <a href="http://www.accesstoinsight.org/tipitaka/mn/mn.010.nysa.html">Satippathana Sutta</a> and the <a href="http://www.accesstoinsight.org/tipitaka/mn/mn.118.than.html">Anapanasati Sutta</a> where the Buddha explains their techniques. I also strongly suggest looking for books that cover detailed explanation for these. Finally, there are a lot of questions regarding meditation here, I suggest looking up for those as well.</p>
