Why am I seeing double in one eye? ("monocular diplopia")

*I am already planning to go in to the eye doctor at the earliest time possible but they are not open until Monday and I am a little concerned so I am curious if anyone has expertise or experience with this phenomenon.

About a month ago I got an eye exam and a new prescription for contacts. The doctor switched me to a different brand of lens that was supposed to be “more breathable” due to eye redness I was showing, but I hated the lenses - they seemed to dry out my eyes more and make them very red, plus I was seeing multiple images around light sources. I stopped wearing them and returned them for the brand I was using before, which feel fine. BUT:

A few days ago, I noticed distinctively that I am seeing a double image which is very faint, and just below and to the left of the main image - and it’s only in my right eye. I have tested it enough to be sure that this is independent of the lenses: whether I am wearing the (new) contacts, my glasses, or no lenses at all, the image is still there. I hoped it might be due to muscle fatigue and just go away but it has persisted.

Wiki has a short blurb saying this is called “monocular diplopia” and is somewhat rare. It says it "includes the consideration of such conditions as corneal surface keratoconus, a structural defect within the eye, a lesion in the anterior visual cortex (rarely cause diplopia, more commonly polyopia or palinopsia) or non-organic conditions. " What non-organic conditions? If I had a distortion of the cornea (keratoconus) wouldn’t they have noticed that on the eye exam I just had?

It seems to have happened somewhat suddenly, but it’s possible I was experiencing it longer before I actually noticed it, because it is so subtle. It’s most noticeable when I am trying to read - but now that I have noticed it it’s bothering the hell out of me. Is it possible the other lenses damaged my eye? How else could this happen so suddenly?

I did not read the Wikepedia entry, so I’ll try to get over to it soon.

In general, most double vision (dipolpia) is from a problem yoking both eyes together or matching the images received from both eyes along the neural pathways or back in the brain. So you don’t get diplopia in one eye. Binocular diplopia can be a medical emergency so we pay a lot of attention to it.

The exception to diplopia being binocular is refraction problems, usually at the cornea level. In other words, the light is broken up incorrectly as it passes through a single cornea and creates a double image.

When we seen a person complaining of monocular diplopia our first thought is that they are a nutcase (this is the medical term for what wikipedia politely calls a “non-organic” condition). “Non-organic” means no physical explanation, therefore nutty. Then we remember cornea problems can also cause it, so we look there. :wink: FWIW I have a very annoying monocular diplopia in a previously lasiked eye. Refractive problem in my case, although I am definitely a bit nutty.

However in your case you are not a nut and it’s overwhelmingly likely to be related to the effect of your contact on the cornea. It is not likely to be an emergency unless you are having pain. It is not from muscle fatigue; as mentioned above, monocular diplopia is not a problem related to binocular vision.

Hope this helps. Do not forget it’s not advice; just an explanation of what is common. What is rare might kill you, of course, or blind you.

Right, except the problem is that I am experiencing it even when I take my contacts out - that is what concerns me. I was having a similar (worse) problem with the other lenses that went away when I stopped using them, but this is persistent even without having the lenses in. And it is definitely in only one eye.

Also I’m mildly myopic (prescription -2) and have never had astigmatism or glaucoma, if that helps. I know only the doctor can give me any real advice, but the one who prescribed my lenses seemed like kind of a bimbo who I was surprised made it through medical school and I am worried because she doesn’t seem to know what she is talking about. I think I am going to ask for a different doctor this time…

INAD, see your ophthalmologist, YMMV, etc., etc., etc…

My husband had monocular diplopia and it turned out it was an early sign of a cataract developing. It’s been several years now. His eye doc. is monitoring the progression of the cataract. Nothing else to report.

I should have been more clear.
I did read that your problem persisted when taking off the contact. However the contact can have an effect on the cornea that persists after its removal. This could be a small amount of cornea distortion, or edema, or foreign material or whatever. I don’t want to attempt a diagnosis, obviously.

New contacts followed by monocular diplopia is likely–likely, mind you–to be a refractive problem at the level of the cornea. While an error of refraction can occur anywhere along the light path from cornea to retina, the money here is on the cornea.

The one who prescribed your contacts is likely to be an optometrist, by the way. An opthamologist (MD specialist) is the one who would typically handle a persistent diplopia…

Thanks - that does offer some insight. If it really was an effect of the new contacts (which I have since switched back to the old ones), is that something that is generally temporary or permanent? I notice if I focus really hard on a single point I can make the double image go away, but as soon as I relax my eye it comes back.

The best advice is to get it diagnosed first. I would be surprised if a contact caused a permanent problem with monocular diplopia, but step 1 is to find out the actual cause.

I have the same issue in my right eye. One image is overlayed directly above the other but more faint. Only in one eye. I had glasses prescribed but they didn’t help. After a year of headaches trying to wear them I stopped. I tried focusing on my computer screen with just my right eye. Thats when I realized the issue. Text going sideways is doubled. Verticle lines looked normal & sharp because the overlay was in line with them. But reading is terrible. My photograpy is difficult without the right eye So dont wear my glasses, and I have been living with it since cause I figured optometrist dont actually do any practical testing for issues like this. This started when I was about 23 or 24. Now I am 30. Maybe I will look into seeking an opthamologist. Thanks for your info ‘freckafree’ I hope it s not cataracts D:

I discovered that this happens when my eyes are really dried out. You mention that the contacts dry out your eyes. Have you tried going without the contacts for 24 hours and using rewetting drops?

I had a problem with faint double vision when I was trying out CRT a few years ago, so I am placing a bet on corneal staining. Basically small abrasions from your new contacts or, in my case, a buildup of cells in one area due to the lens not fitting right. I had to have fluorescein so many days in a row I had a persistent yellow stain on my sclera for days and days. Luckily it was covered up by my eyelid so I didn’t look like a freak.

I also have monocular diplopia. Severe in the left eye. Mild in the right eye unless I stare at a computer screen for many hours.

Mine was diagnosed as due to “Mapdot fingerprint dystrophy” and the doctor suggested the cause was staring at computer screens without blinking. She prescribed three remedies – Genteal artificial tears every several hours, Vidisic ophthalmic gel, and high-% saline solution, though I’m now using only the artificial tears regularly. She said I could probably be cured with laser surgery; I would try that if the problem got worse, or if I were a younger man.

I can vouch for this! I even worried I was going nutty when I started seeing double with one eye closed. :cool: I paid several visits to “the best ophthalmologist” in our region, and I think he still thought I had binocular diplopia when he gave up on me. I then went to the best eye hospital in all of Southeast Asia and, I’m afraid, raised my voice (some fellow Dopers have probably noticed how easily irritated I am :smack: ) when the doctor started the interview by asking binocular-type questions.

I can’t read with my left eye (or, even with right eye, without a magnifying glass for very tiny fonts) but I’m happy to live with my vision as is. It was disconcerting, however, before it was diagnosed.

It should be noted that this thread is two years old; it would be nice if Rigamarole could pop back in to update us.

Question to Chief Pedant. You say:

But I have had for nearly ten years. It started when I was star-gazing one night and could not fuse the images of a star. My doctor was not disturbed although he did send me to an ophthalmologist who was not disturbed but prescribed a prism. Since then it has gotten worse and I now have prisms in both eyes (2 1/2 up in one eye and 2 1/2) down in the other, but they still don’t seem to worry. So why do you say it is an emergency?