Investigating causes of diplopia to minimise morbidity and mortality

Investigators said it is crucial for clinicians to understand the common causes of diplopia and a system to differentiate between urgent and nonurgent cases. Image credit: ©Nicole Kwiatkowski – stock.adobe.com

A new study emphasised that patients who present with diplopia should be referred expeditiously for appropriate care and treatment to reduce morbidity and mortality. Mariam Issa, MD, and colleagues emphasised the importance of urgent neuro-ophthalmologic referral for patients with diplopia to allow for appropriate evaluation and investigations.¹ She is from the Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Ontario, Canada.

Diplopia can result from a number of different causes ranging from refractive errors, which are benign, to life-threatening emergencies, such as aneurysmal compression of cranial nerves,² the investigators explained.

“It is important for clinicians first encountering a patient with diplopia to understand its common causes and to have an approach for these patients to differentiate between urgent and nonurgent cases. Although it was previously found that 16% of patients presenting with diplopia to an emergency department have a life-threatening condition,³ little is known about the prevalence of systemic and ocular adverse effects specifically in patients referred for neuro-ophthalmic evaluation with the chief complaint of diplopia,” Issa and her colleagues said.

They explained the difference between this and previous studies that focused on diplopia. They said, “No comprehensive study exists on the aetiologic classification, clinical features and assessment of morbidity/mortality of all patients referred for the evaluation of diplopia to a tertiary neuro-ophthalmological practice where referrals are received from other ophthalmologists, neurologists, general practitioners and optometrists. Patients seen in this setting are unique in that not only do they experience a variety of diplopia aetiologies but also have a previous record of being seen by other practitioners. Therefore, this study offers the opportunity to ascertain the potential for morbidity and mortality (potential for loss of vision, progression of symptoms or systemic morbidity or mortality) in patients referred for evaluation of diplopia based on their final diagnosis,” they emphasised.

Retrospective chart review

The researchers reviewed the charts of patients seen by tertiary neuro-ophthalmologists in a tertiary neuro-ophthalmology practice between 2 December, 2021, and 21 May, 2022. Their study included all patients who had been referred due to the complaint of diplopia.

The primary study outcome was the potential for vision loss, symptom progression or systemic morbidity or mortality in patients who had not been referred to a neuro-ophthalmologist.

A total of 196 patients (48.5% women; mean age, 61 years) were identified who had been referred for diplopia.

“The most common final diagnosis reached following neuro-ophthalmology consultation were cranial nerve palsies (38.3%, 75 of 196), convergence insufficiency and decompensated phoria (22.4%, 44 of 196), non-neuro-ophthalmic causes (19.9%, 39 of 196), thyroid eye disease (4.5%, 9 of 196), myasthenia gravis (3.5%, 7 of 196) and multiple sclerosis (6 of 196, 3.1%). Based on the final diagnosis, 15.3% of patients referred to the neuro-ophthalmology service for diplopia had the potential for morbidity or mortality,” the investigators reported.

The morbidities to which they referred were visual loss resulting from severe papilloedema from untreated idiopathic intracranial hypertension in 1% (two of 196) and systemic morbidity or mortality in 3.0% (six of 196) from the final diagnosis, ie, brain aneurysms in two of 196, pituitary apoplexy in one of 196, anaplastic glioma in one of 196, and other malignancies in two of 196.

Other patients were diagnosed with thyroid eye disease (nine of 196), myasthenia gravis (seven of 196), and multiple sclerosis (six of 196), representing 11.2% (22 of 196) of the study population.

Of the patients who had a pre-referral neuroimaging study, 30.1% required additional neuroimaging after neuro-ophthalmic consultation.

Dr Issa and colleagues concluded that “17.1% of all new patients seen at a tertiary neuro-ophthalmological practice were primarily referred for the evaluation of diplopia, and 15% of all patients referred for diplopia harboured the potential for morbidity and mortality without correct diagnosis and management. As diplopia can be caused by life- and vision-threatening aetiologies, the low accuracy of prereferral diagnosis and neuroimaging found in this study emphasised the importance of urgent neuro-ophthalmologic referral. It is important for clinicians to have an appropriate approach when encountering patients with diplopia to provide optimal care, prevent unnecessary investigations and initiate urgent referral to neuro-ophthalmology when necessary.”

References

1. Issa M, Cioana M, Popovic MM, et al. Analysis of diplopia referrals in a tertiary neuro-ophthalmology center. Can J Ophthalmol. 2025; https://doi.org/10.1016/j.jcjo.2025.03.001

2. Najem K, Margolin E. Diplopia. 2022; StatPearls.StatPearls Publishing, 2022 Accessed November 5, 2022; http://www.ncbi.nlm.nih.gov/books/NBK441905/

3. De Lott LB, Kerber KA, Lee PP, Brown DL, Burke JF. Diplopia-related ambulatory and emergency department visits in the United States, 2003–2012. JAMA Ophthalmol. 2017;135:1339-1344.