3. Rule Out Worst-Case Scenarios
Acute-onset, constant diplopia with additional neurologic symptoms should be considered urgent until proven otherwise.
A sudden onset of diplopia increases the likelihood that the central nervous system has been injured through trauma or ischemia. The presence of any additional signs or symptoms, especially pupil involvement and dysfunction of multiple cranial nerves, should raise a red flag.
Inquire about the following with the patient:
Ocular or facial pain
Cranial nerve testing is extremely helpful in ruling out life-threatening diagnoses and isolating the cause of the diplopia. Some of the most important abnormalities to look for are decreased visual acuity, facial sensation, and strength of facial musculature.
Two of the worst-case scenarios for diplopia are as follows:
Diplopia with asymmetric pupils
MRI and MRA/CTA should be performed immediately to rule out an aneurysm or space-occupying lesion. This is considered an emergency until proven otherwise.
Diplopia with involvement of multiple cranial nerves
The affected cranial nerves help to isolate the impacted portion of the brain. Isolated cranial nerve palsies are more often due to underlying ischemic issues, such as diabetes or hypertension; but when multiple cranial nerves are affected, the cause is much more likely to be a life-threatening condition like tumor or hemorrhagic stroke. Pathology involving the cavernous sinus has the propensity to affect multiple cranial nerves because of the close proximity of these nerves when traveling through the sinus. Arteriovenous fistulas, tumors within the cavernous sinus, and intracavernous aneurysms may all be present with diplopia.
4. Consider the Most Likely Causes
Once the most serious systemic causes of diplopia have been excluded, focus on the most probable causes.
If the patient wears glasses, determine whether the diplopia occurs only with the glasses on. The patient may not be aware that the diplopia resolves without the glasses if they are being worn regularly.
If the patient experiences diplopia only at near, convergence insufficiency should be considered. This condition may affect patients of a broad range of ages. Patients usually become symptomatic after near work. This type of diplopia is intermittent and increases with fatigue.
Patients with diplopia should be questioned specifically about their ocular history. Some patients who had strabismus in childhood and underwent surgery or patching become symptomatic later in life as the misalignment makes a subtle return.
Additionally, a decompensating phoria often causes diplopia as the patient loses the ability to maintain fusion. This condition can sometimes be treated with a temporary or permanent prism ground into the spectacle prescription. These patients usually complain of intermittent diplopia that gradually worsens.
These causes of diplopia are not serious and can be addressed by a referral to an ophthalmologist or optometrist.
Medscape Ophthalmology © 2019 WebMD, LLC
Any views expressed above are the author's own and do not necessarily reflect the views of WebMD or Medscape.
Cite this: Double Trouble: 4 Things to Do in Patients With Diplopia - Medscape - Nov 13, 2019.