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The effects of certain drugs on a subject's vision

television82

Bluelighter
Joined
Oct 28, 2011
Messages
53
Firstly, I've posted this in the ADD section as I am looking for the most accurate scientific answer I can get. Although I'm not yet myself knowledgeable enough to know of the biochemistry and neuroscience behind the answers I am looking for, I am extremely interested in discovering them and learning to understand them. This curiosity stems from both the fact that I seem to get more pronounced visual side-effects from particular drugs than others and the fact that I have a developing interest in biochem and neuroscience and hope to be studying such material at University in some capacity very soon.

My first question is basically, what is the biology/chemistry behind the visual effects that are caused by certain drugs, and why can it be more pronounced in certain indivudals.

The major effect I'm referring to is diplopia, or double vision. Or at least I think this is what it is. It is blurry vision, sometimes perceived as double vision, which can be almost entirely overcome by closing or covering one eye. This happens to me on nearly every recreational drug I take including MDMA, and all opiates and benzodiazapines when taken in high enough doses. The blurry vision, and the 'covering one eye fix', seems to be the same with all categories of drugs despite the fact that MDMA causes significant dilation of the pupil, whilst opiates cause constriction of the pupils leading to 'pinpoint pupils'. I don't understand the correlation in visual impairment despite the effects on the pupils being basically polar opposites in the cases of opiates or benzos.

One more note on the visual side-effects caused by MDMA, especially at high doses, is the sensitivity to light caused by the drug.When I take enough of this substance I cannot read any sort of text at all, sometimes even large text. Text on a computer or phone screen is even harder to read as the backklight completely dominates my vision. I can logically assume that the dilation caused by the MDMA leads to excessive light being allowed to enter the back of the eye, which leads to light becoming more pronounced, which therefore overwhelms the 'dimmer' light entering the back of the eye, which leads to bright white light being so much more prevalent and hence the inability to distinguish dimmer text.
So I guess my second question is are my amateur logical deductions correct? And if so could anyone please neaten them up, and introduce me to any vocabulary that I could have used in place of other terms. And can anyone give me a more advanced explaination of hte phenomenon, or at least point me in the right direction to discover it myself.
Finally, why do I get this particular visual impairment from MDMA more than anyone else? Despite taking the same dose, or even sometimes less, than others I'm always much more useless when it comes to reading any sort of text when under the influence of MDMA? What is it in my biochemistry that leads me to be particularly susceptible to this?

Thanks (and again, if this is not advanced enough for ADD please at least throw me some terms/mechanisms/ect to look up for myself rather than just dismiss/ignore me)
 
http://tripzine.com/pit/signal_theory_poster.pdf
This may be of interest for more general efects of 5-ht2a agonists on vision and sensory processing. MDMA does have some effects as a 5-HT2a agonistic psychedelic but its primary mode of action is the release of monoamines (norepinephrine, serotonin, dopamine).

The double vision may be caused by dysregulation of ocular tracking muscles. Many people report vision disturbances ("eye wiggles") during peak MDMA experiences. I assume this is due to muscular issues rather than any deficit of vision processing. (Shivering/twitches on MDMA is also known)
You are probably correct that the loss of ocular acuity is due to extreme pupil dilation and/or loss of the accomodation reflex.

Both of these are likely caused by the massive release of norepinephrine caused by MDMA, and can be quelled somewhat by reducing your dose level by 10-20mg usually. (assuming you're dosing "above threshold", but not 200mg+ - in that case try 100-120mg)
 
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Nystagmus is the involuntary eye movement, twitch-like action that reminds of saccadic eye movement.

Loss of acuity can also be associate with pupil dilation among other things. If severe enough it can make vision vague such as with anticholinergic e.g. datura.

Diplopia is also associated with MDMA use but I think it has a slightly different cause than nystagmus: even if the eyes provide badly corresponding data to the brain, under normal circumstances it can still be computed into a useful image. However under the unfluence of drugs there can be dysregulation of this image processing and I think this results in less tolerance of visual incoherence.

Blurry vision probably could not be processed into useful images even with a sharp brain - I think this is a distinction to be made:

dysregulation of
- the brain
- the eye muscles involved with movement of the eye itself, and
- pupil dilation / contraction (constriction?)
 
The NE aspect of eye wiggles makes more sense than the serotonin part IMO- kratom strains especially with high levels of the stimulatory yohimbe alkaloids give TERRIBLE eye wiggles. I think MDMA just makes those eye wiggles more difficult to process and more disorientating. The kratom eye wiggles are just like MDMA except without the trippy-ness . Pupil dilation makes for less ocular control often... at least for differentiation between foreground and background.

-lenses
 
I am also curious about opiate/oids effect on the eyes, when I do more than a tiny amount of any opiate/oid I can't focus on anything with both eyes at all, its awful trying to read a book or be on a computer with one eye squeezed shut. Is there any way to combat this side effect of opiates? I doubt there is, but it would be awesome, as that is the only part of opiate's effects that makes me non functional (unless nodding). Its pretty weird looking to be in class with one eye shut, and I can't see the powerpoint/board with both eyes open.

Edit: THis is totally different than the eye wiggles I have had on MDMA or amphetamines, I don't think the two are necessarily at all related.
 
Let me see if I can find an advanced narcotic detection source and I'll send the link.
http://www.drugrecognitionexpert.us/forum/the-seven-drug-categories/narcotic-analgesics/

This category includes the opiates, such as morphine, codeine, percodan, heroin, meperidine, methadone, fentanyl, and numerous others. These drugs relieve pain, but also produce sedation. The specific effects include constricted pupils, depressed vital signs, slow and deliberate movements, and forgetfulness. These drugs do not produce horizontal gaze nystagmus. Although these drugs are frequently injected, more users, because of concern over the spread of infectious disease through the sharing of hypodermic needles, are insufflating (intranasal administration) and inhaling drugs such as heroin. These drugs are known for their physically addictive qualities, as well as for the extremely unpleasant, though not life-threatening, withdrawal syndrome.

Not as in depth as I had thought it would be.
 
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on crazy doses of amphetamines, looking at the stars twinkle would give me crazy visual changes like double vision. I guesss methamphetamine improves vision? made the illusory twinkle weirder like double vision and greater differences between red and blues making up a white.
 
Hi guys,
New to this forum but glad to see some interesting stuff and read some cool peoples ideas,
I found this a while back - may be of interest to you. not so much about biology, but more about visual mathematical representations of very low level hallucinations in the brain. Related to our good old friend mr Turing and his mathematics, who as people with interests in neuroscience and cognitive science - the man is certaintly a good thinker.

http://plus.maths.org/content/os/issue53/features/hallucinations/index
 
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