Double vision is a cause of dry eye, refractive issues and also of diseases which affect the eye muscles, cranial nerves or the brain. Also referred to as diplopia, double vision may affect one eye or present when both eyes are open. Sudden double vision in particular when associated with weakness, severe headache, unsteadiness, pupil changes or drooping of the eyelid requires prompt medical evaluation.
What Is Double Vision?
Double vision is a condition in which you see two of the same image. Images may present themselves side by side, on top of each other, or in part overlay. Also it is noted that which eye is affected, monocular or binocular, this information helps us to determine the double vision causes.
Monocular diplopia remains when the healthy eye is covered. That which affects the cornea, tear film, lens or refractive system usually causes this. Binocular double vision goes away when either eye is covered. It typically appears when the eyes are not aligning properly.
Vasan Eye Care’s guide to diplopia provides further information about its types, diagnosis and management.
| Type | What happens | Common double vision causes |
| Monocular | Double image remains in one eye | Dry eye, astigmatism, cataract, corneal irregularity |
| Binocular | Double image disappears when either eye closes | Squint, cranial nerve palsy, thyroid eye disease, myasthenia or neurological disease |
| Sudden binocular | Develops unexpectedly with both eyes open | Nerve palsy, stroke, orbital disease or other neurological causes |
What Are the Common Double Vision Causes?
Some eye issues present with diplopia. An unstable tear film which in turn may distort incoming light, also cataracts or an irregular cornea shape can produce more than one image in a single eye. Vasan Eye Care provides info on dry eye treatment and cataract surgery which they do when these conditions affect vision.
Binocular double vision causes is a result of eye alignment issues. Cranial nerves III, IV and VI control key eye movements. Disease of these nerves may cause both eyes to not agree on the same target.
Other double vision causes include thyroid eye disease, squint, orbital inflammation and myasthenia gravis. Issues of the brainstem and other neurological paths also play a role in eye movement.
Conditions affecting the optic nerve usually cause reduced or altered vision rather than typical diplopia. However, associated neurological symptoms may require assessment for conditions linked with optic neuritis symptoms or retrobulbar neuritis.
When Is Sudden Double Vision an Emergency?
New sudden vision issues are what pay attention to in the case of double vision. Sudden onset may also indicate an issue with the nerves, brain or blood vessels in addition to the eye surface.
A study was done on 260 patients that presented to the emergency department with diplopia which is found to have secondary causes in 35.8%. Out of those secondary diagnoses stroke was the cause in 45.2%. These results are for the emergency department population that studied and do not necessarily apply to all cases of double vision.
| Symptom pattern | Possible concern | Recommended response |
| Sudden double vision alone | Cranial nerve or neurological disorder | Prompt medical assessment |
| Double vision with weakness, numbness or speech difficulty | Possible brain or vascular problem | Emergency assessment |
| Severe headache with pupil enlargement or drooping eyelid | Possible compressive nerve problem | Immediate emergency care |
| Double vision after head or eye injury | Orbital or neurological injury | Urgent assessment |
| Eye pain with new visual change | Orbital, inflammatory or nerve disorder | Prompt ophthalmic review |
A clinical report notes that for recent binocular diplopia which also brings in brainstem symptoms a urgent neurology work up is required. Also in the case of acute third cranial nerve palsy requires prompt evaluation which may be a result of an aneurysm. Also patients should note other double vision warning signs which include poor balance, facial weakness, confusion, new onset of droopy eyelid and unequal pupils.
How Are Double Vision Causes Diagnosed?
Diagnosis begins with a note of when the symptom appeared, if it is constant, and if closing either eye removes it. Also vasan eye care checks eye position and movement, visual acuity, the reaction of the pupils and the front and back structures of the eyes.
Testing to include refraction, slit-lamp exam, dilated fundus exam and eye alignment assessment. Blood tests or neuroimaging may be done at the time of exam if it is seen as thyroid disease, myasthenia, cranial nerve dysfunction or another neurological condition.
Someone experiencing both double vision and sudden blurry vision needs careful assessment because the two symptoms can have different causes.
How Is Diplopia Treated?
Treatment is based fully on the double vision causes as determined by the exam. For dry eye or refractive issues vasan eye care may try eye surface treatments or new corrective lenses. In case of cataract related monocular diplopia improvement may be seen after they manage the cataract.
Binocular diplopia may present with the use of prisms, temporary occlusion, treatment of the base medical issue or in a select few cases eye muscle surgery. For neurological causes they have condition based management as opposed to a sole focus on suppression of the double image.
Persistent, recurrent or unexplained symptoms may need neuro-ophthalmology assessment, particularly when eye movement abnormalities occur with other neurological features.
Eye Care at Vasan Eye Care
Vasan Eye Care does treatment for double vision and unexplained eye misalignment. What they do may include eye movement tests, study of the pupils, refraction, retina evaluation or may send you to a neurologist for further investigation.
Sudden double vision or worsening double vision warning signs should not be ignored. An ophthalmologist may determine that the issue is with the eye, eye muscles, cranial nerves or the visual pathways and will advise what level of care is needed.
Frequently Asked Questions
1. What are the most common double vision causes?
Common double vision causes include dry eye, astigmatism, cataract, squint and issues with the nerves that control eye movement. Also in play are thyroid eye disease and neurological disorders which in turn may see the issue affect both eyes.
2. Can diplopia go away on its own?
Some diplopia will improve when a temporary or treatable cause goes away. But if you have new or persistent double vision it needs to be evaluated as treatment and recovery depend on the base condition which may not be apparent from the symptom alone.
3. Is sudden double vision always serious?
Sudden double vision may not be a sign of a serious condition, but it does require prompt evaluation. When it is associated with a headache, change in pupil size, weakness, numbness, loss of balance, speech difficulty or any other neurological symptoms urgency increases.
4. What double vision warning signs should not be ignored?
Important double vision warning signs include abrupt onset of symptoms, very painful headache, unequal pupils, drooping of the eyelid, weakness, numbness, balance issues, speech difficulty or symptoms that appear after head trauma. These features require prompt medical attention.
References
- Causes of Diplopia in the Emergency Department: Diagnostic Accuracy of Clinical Assessment and of Head Computed Tomography
https://pubmed.ncbi.nlm.nih.gov/23788113/ - Approach to Patient With Diplopia
https://pubmed.ncbi.nlm.nih.gov/32777577/