Acquired Ocular Motor Nerve Palsy in Neurology Clinics: A Prospective Multicenter Study

Clinical spectrum and its association with recovery patterns in patients with acquired isolated ocular motor nerve palsies - an observational study

Purpose: To study the clinical spectrum and recovery patterns in patients of acquired isolated ocular motor nerve palsies (OMNPs). Methods: Patients above 5 years of age with various etiologies of OMNPs were included. Demographic and ocular details were recorded, and a squint assessment was performed. Recovery patterns at 3 and 6 months were noted. Results: OMNP was more common in adults, in the order VI > III > IV nerve. Ischemic cause (35%) was followed by idiopathic (26.3%). III nerve palsies were all unilateral, of which all ischemic palsies were pupil-sparing. By 6 months, >50 patients showing complete recovery had ischemic and idiopathic palsies. Smaller baseline deviation correlated with better recovery. Conclusion: Acquired isolated OMNPs are mostly ischemia-related, with >80% of cases fully recovering by 6 months. VI nerve palsy of ischemic or idiopathic etiology and small baseline deviation were associated with self-recovery.

Etiological distribution of isolated oculomotor nerve palsy: analysis of 633 patients and literature review

BACKGROUND AND PURPOSE

The etiological distribution of oculomotor nerve palsy has varied amongst the studies. This study aimed to define the clinical features and underlying etiologies of isolated oculomotor nerve palsy by recruiting patients from all departments in a referral-based university hospital.

METHODS

The medical records of 672 patients who had a confirmed diagnosis of isolated oculomotor nerve palsy at all departments of Seoul National University Bundang Hospital, Seongnam, South Korea, from 2003 to 2020 were reviewed. A proportion of the etiology of isolated oculomotor nerve palsy was also compared with that of patients pooled from the previous studies that were searched on PubMed in May 2022.

RESULTS

The most common etiology was microvascular (n = 168, 26.5%), followed by vascular anomalies (n = 110, 17.4%), neoplastic (n = 86, 13.6%), inflammatory (n = 79, 12.5%), idiopathic (n = 60, 9.5%) and traumatic (n = 53, 8.4%). Neurologists were mainly involved in the management of microvascular and inflammatory oculomotor nerve palsies whilst ophthalmologists mainly participated in the care of idiopathic, neoplastic and traumatic palsies. Neurosurgeons mostly took care of oculomotor nerve palsy due to vascular anomalies.

CONCLUSIONS

The proportion of etiologies of isolated oculomotor nerve palsy may differ according to the specialties involved in the management. The results of previous studies on the etiological distribution of isolated oculomotor nerve palsy should be interpreted with this consideration.

Acupuncture therapy for isolated ischemic oculomotor nerve palsy: A case report

BACKGROUND

Isolated ischemic oculomotor nerve palsy as a type of ophthalmic disease is rarely observed in clinical practice. Quality of life is frequently impacted by isolated ischemic oculomotor nerve palsy due to its lack of treatment options and long-term visual impairment. We describe an acupuncture-treated instance of isolated ischemic oculomotor paralysis.

METHODS

Acupoints including Jingming (BL 1), Chengqi (ST 1), Cuanzhu (BL 2), and Sizhukong (TE 23) on the right side, and bilateral Fengchi (GB 20), Waiguan (TE 5), Hegu (LI 4), and Zulinqi (GB 41) were selected for needling. Each treatment lasted for 30 minutes, once every other day. Acupuncture treatment was administered for a total of 11 times.

RESULTS

Acupuncture is a promising treatment option for isolated ischemic oculomotor nerve palsy.

CONCLUSIONS

Ischemic oculomotor nerve paralysis can affect the quality of life of patients. Acupuncture intervention can promote the recovery of the disease is a very effective treatment measure.

Ocular Motor Cranial Nerve Palsies and Increased Risk of Primary Malignant Brain Tumors: South Korean National Health Insurance Data

The aim of this study was to investigate the association between ocular motor cranial nerve palsies (OMCNP) and the occurrence of primary malignant brain tumors in a Korean population, using the national sample cohort database from Korea National Health Insurance Service (KNHIS). KNHIS data between 2010 and 2017 were analyzed. Our sample encompassed 118,686 participants, including 19,781 from a recently diagnosed OMCNP cohort and 98,905 from a matched control cohort through a 1:5 propensity score matching based on age and gender. To counteract the issue of reverse causation, we integrated a one-year time lag in our sensitivity analysis. Study participants were followed up until 31 December 2019. Cox proportional hazard regression analysis was used to compute the adjusted hazard ratio (HR) for primary malignant brain tumors according to the OMCNP diagnosis. Additionally, we performed a subgroup analysis to discern effects of various factors on the association between OMCNP and primary malignant brain tumors. HR for primary malignant brain tumors was 3.272 (95% confidence interval [CI]: 2.294 to 4.665) in the OMCNP cohort compared to the control cohort in a fully adjusted model for age, sex, socio-economic status, smoking, drinking, regular physical exercise, hypertension, diabetes, dyslipidemia, obesity, chronic kidney disease, and human immunodeficiency virus infection. Further subgroup analysis revealed that the risk of primary malignant brain tumors was significantly increased in women with OMCNP compared to men with OMCNP (HR: 5.118 in women vs. 2.441 in men, p = 0.0440), and in those aged <65 years than in those aged ≥65 years (HR: 6.951 in age < 65 years vs. 1.899 in age ≥ 65 years, p = 0.0006). Our population-based cohort study demonstrated a significantly increased risk of subsequent primary malignant brain tumors in patients with OMCNP. Particularly, OMCNP-afflicted women aged below 65 manifested a heightened probability of developing primary malignant brain tumors compared to those devoid of OMCNP.

COVID-19 and sudden-onset ocular neurogenic palsy in prior healthy patients: a systematic review

BACKGROUND

The aim of this systematic review is to identify cases of neurogenic ocular palsy in the presence of COVID-19 and to document patient characteristics, type of palsy and possible aetiologies.

METHODS

A systematic search of PubMed, Medline and CINAHL databases was conducted on the 6th of January 2023 to identify cases of neurogenic ocular palsy in patients with current or previous COVID-19 infection. Data were pooled to summarise the neurogenic palsy, patient clinical characteristics and proposed palsy mechanisms.

RESULTS

The combined database search yielded 1197 articles. Of these, 23 publications consisting of 25 patients met the inclusion criteria. Most patients were male (68%) and ranged in age from 2 to 71 years (median=32.7, SD=21.4). Seven patients (28%) were children aged 2 to 10 years old. Abducens palsies were most common (68%) and the most common ocular presentation was diplopia (76%) with an average time of onset 15 days from testing positive to COVID-19 or having symptoms of the virus. Proposed mechanism of development of a neurogenic palsy secondary to COVID-19 infection was classified into one of three categories: vascular/thrombotic, a viral neuro-invasive or inflammatory virus-mediated immune response.

DISCUSSION

This study suggests that COVID-19 infection may be linked to oculomotor, trochlear and abducens nerve palsies and the underlying mechanisms may vary but are difficult to definitively establish. Further studies investigating the onset of neurogenic palsy secondary to COVID-19 infection is required.

Cerebral small vessel disease as imaging biomarker predicting ocular cranial nerve palsy of presumed ischemic origin at admission

Ocular cranial nerve palsy of presumed ischemic origin (OCNPi) is the most common type of ocular cranial nerve palsy (OCNP) in patients aged ≥ 50 years; however, no definite diagnostic test exists. As diagnostic criteria include clinical improvement, diagnoses are often delayed. Diagnostic biomarkers for OCNPi are required; we hypothesized that cerebral small vessel disease is associated with OCNPi. We analyzed 646 consecutive patients aged ≥ 50 years with isolated unilateral OCNP who underwent work-ups at two referral hospitals. White matter hyperintensities (WMHs), silent infarctions, and cerebral microbleeds (CMBs) were assessed. In multivariate analyses, mild (grades 1-3) and moderate to severe (grades 4-6) WMHs were significantly associated with OCNPi compared to OCNP of other origins (odds ratio [OR] 3.51, 95% confidence interval [CI] 1.91-6.43, P < 0.001; OR 3.47, 95% CI 1.42-8.48, P = 0.006, respectively). Silent infarction and CMBs did not remain associated (OR 0.96, 95% CI 0.54-1.70, P = 0.870; OR 0.55, 95% CI 0.28-1.08, P = 0.080, respectively). Associations between WMH and OCNPi remained after excluding patients with vascular risk factors. In conclusion, the presence of WMH could independently predict ischemic origin in patients with isolated unilateral OCNP at early stage of admission.

Trends in Etiologies, Demographics, and Neuroimaging in New-Onset Adult Strabismus at an Ophthalmic Emergency Department

PURPOSE

To evaluate new-onset strabismus in adults presenting to an ophthalmic emergency department, and to identify which patients require neuroimaging.

METHODS

This was a retrospective review of electronic medical records of patients 18 years and older who presented to an ophthalmic emergency department between January 1, 2019 and December 31, 2020 with new-onset strabismus. Data regarding demographics, causes, neuroimaging, and resolution were recorded and analyzed.

RESULTS

Of the 557 patients in the current study, 54.8% were men and the mean age was 57.3 ± 16.7 years (range: 18 to 92 years). Most patients (72.4%) presented with diplopia. Esotropia was the most common ocular misalignment (43.6%) and was more common in women than men (51.6% vs 37.0%, respectively) (P = .001). The most common diagnoses were cranial nerve palsies (66.8%) for both sexes and all age groups, with the most common etiology being microvascular (48.1%) for patients 50 years and older and idiopathic (20.1%) for patients between 18 and 49 years old. The incidence of cranial nerve palsies was significantly higher in older patients (P < .001). Neuroimaging was performed in 58% of patients (n = 323), of whom 37.2% (n = 120) had abnormal findings. The most common abnormal neuroimaging finding was mass for all age groups and sexes (19.2%). Patients with cranial nerve palsy and microvascular etiology had a significantly lower proportion of abnormal neuroimaging findings (P < .001).

CONCLUSIONS

Most cases of new-onset strabismus in adults presenting to the emergency department were due to cranial nerve palsy, particularly in older patients. Despite high rates of neuroimaging, patients with cranial nerve palsy had mostly normal findings. The current study supports the belief that neuroimaging may be deferred in patients older than 50 years with micro-vascular risk factors. [J Pediatr Ophthalmol Strabismus. 2022;59(4):269-273.].

Clinical outcomes and etiology of acquired sixth cranial nerve palsy

ABSTRACT

The objective of this study was to investigate the difference in clinical features according to age and factors affecting recovery of acquired sixth cranial nerve (CN6) palsy.A total of 156 patients with acute CN6 palsy between March 2016 and August 2021 who were followed up for at least 3 months were included in this study. Etiology, rate of recovery, and factors associated with recovery were retrospectively investigated.The average age of patients with CN6 palsy was about 60years and the mean duration of recovery was about 2.5 months. Of 156 patients, 72 (46.15%) had a microvascular etiology and 25 (16.03%) patients had a brain vascular lesions. Brain neoplasm, trauma, and "others" were found in 10 (6.41%), 11 (7.05%), and 15 (9.62%) patients, respectively. Among the total of 156 patients, 28 (17.95%) failed to completely recover. Non-isolated CN6 palsy with other cranial nerve palsies were recorded in 29 (18.59%) cases. Comparison of age (<50years vs ≥50years), between recovery and non-recovery groups showed that etiology was significantly different.The recovery rate of acquired CN6 palsy was about 82% and about 27% of patients had brain lesions. Also, varying rates and duration of recovery were found according to etiology, so we should be pay attention to diagnosis of causative disease in CN6 palsy patients.

Stroke risk after ocular cranial nerve palsy - A systematic review and meta-analysis

BACKGROUND

Isolated ischemic ocular cranial nerve palsies (OCNP) involving the 3rd, 4th and 6th cranial nerves (CN) are prevalent conditions in ophthalmic practice. However, it is not clearly established whether such patients are at increased risk of stroke after onset of OCNPs.

METHODS

Medline, PubMed, Embase and Cochrane Central registers were systematically searched for eligible studies comparing isolated ischemic OCNPs against matched controls on the subsequent development of stroke with at least two years of follow up. Case reports and series were excluded. Appropriate studies were entered for meta-analysis to determine hazard ratios. Search and data extraction was completed on 22 Feb 2021. Random effect models were used to generate pooled hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

Three studies were suitable for meta-analysis (total n = 2,756 OCNP cases and 21,239 matched controls). The meta-analysis demonstrated a hazard ratio of 5.96 (4.20-8.46 95% CI) of subsequent stroke after isolated OCNP within the first year. The hazard ratio reduced to 3.27 (2.61-4.10 95% CI) after five years although remains raised at 2.49 (1.53-4.06 95% CI) up to 12 years. The highest risk was demonstrated with 3rd cranial nerve palsies. Two additional studies assessed the risk of stroke with newly diagnosed diabetics and compared OCNPs against lacunar stroke. These studies did not demonstrate a significant increased risk of stroke, although they may be statistically underpowered.

CONCLUSION

Ischemic OCNPs represent a significant risk factor for development of subsequent stroke in a similar magnitude to transient ischemic attack within the first year.

Magnetic Resonance Imaging in Diplopia: Neural Pathway, Imaging, and Clinical Correlation

The role of magnetic resonance imaging (MRI) in diplopia is to diagnose various diseases that occur along the neural pathway governing eye movement. However, the lesions are frequently small and subtle and are therefore difficult to detect on MRI. This article presents representative cases of diseases that cause diplopia. The purpose of this article was to 1) describe the anatomy of the neural pathway governing eye movement, 2) recommend optimal MRI targets and protocols for the diagnosis of diseases causing diplopia, 3) correlate MRI findings with misalignment of the eyes (i.e., strabismus), and 4) help familiarize the reader with the imaging diagnosis of diplopia.

The spectrum and differential diagnosis of acquired ocular motor nerve palsies: a clinical study of 502 patients

Background

Ocular motor nerve palsies (OMNP) frequently cause patients to present in an emergency room. In the following study, we report the differential diagnosis of OMNP by use of magnetic resonance imaging (MRI) and CSF examination as a standard.

Method

We performed a data analysis of N = 502 patients who presented with oculomotor, trochlear, and/or abducens nerve palsy in the emergency room of the Department of Neurology, University of Ulm, between January 2006 and December 2019. We report clinical and MRI scan findings in all patients; furthermore, the CSF of 398 patients has been analysed.

Results

Abducens nerve palsies were most common (45%), followed by palsies of the oculomotor (31%) (CNP III) and trochlear nerve (15%). Multiple OMNPs were seen in 9% of our cohort. The most common causes included inflammations (32.7%), space-occupying lesions, such as aneurysms or neoplasms (17.3%), diabetes mellitus (13.3%), and brainstem infarctions (11%). Still 23.4% of the patients could not be assigned to any specific cause after differential diagnostic procedures and were described as idiopathic. One of three patients with an inflammation and 39% of the patients with space-occupying lesions showed additional cranial nerve deficits.

Conclusion

Inflammation and space-occupying processes were the most frequent causes of OMNP, although brainstem infarctions also play a significant role, in particular in CNP III. The presence of additional CNPs increases the probability of an inflammatory or space-occupying cause.

The Neurotropic Varicella Zoster Virus: a Case of Isolated Abducens Nerve Palsy without Skin Rash in a Young Healthy Woman

INTRODUCTION

Varicella Zoster Virus (VZV) is a neurotropic virus whose reactivation can affect the central nervous system (CNS) and manifest as different neurological syndromes usually with dermatological involvement. Extraocular muscle palsies are not commonly described associated with VZV and their presence in the absence of a typical zoster rash is even rarer.

METHODS

Case report of a young immunocompetent patient with unilateral abducens nerve palsy, as an isolated manifestation of VZV infection.

RESULTS

A 25-year-old healthy female presented to the emergency department with a subacute onset of painless horizontal binocular diploplia, over a month. Ophthalmological and neurological examination revealed an isolated right abducens nerve palsy, and polymerase chain reaction of the cerebrospinal fluid identified a VZV infection. There was no skin rash involvement. Other infectious, inflammatory, and autoimmune diseases were excluded. Treatment with intravenous acyclovir and dexamethasone improved but not completely resolved the diplopia and strabismus. The patient was submitted to a medial rectus recession surgery.

DISCUSSION

VZV manifestations in the CNS can occur in healthy young individuals and can manifest in the absence of the typical skin rash. Isolated sixth nerve palsy is a very rare manifestation of VZV infection. Young patients with isolated ocular motor mononeuropathies, even with cardiovascular risk factors, benefit from a CNS-based approach and MRI and lumbar puncture should be considered. Reports show that extraocular muscle palsy associated with VZV is a transient condition and resolve partially or completely after few weeks.

Isolated trochlear palsy as the only presentation of midbrain infarction: a case report

Trochlear palsy often results from traumatic, congenital and microvascular disorders. An intra-axial lesion as a cause of trochlear palsy is uncommon. Moreover, it usually accompanies other neurological deficits. Isolated trochlear palsy as the only presentation of brainstem stroke is unexpected. This current case report describes a 74-year-old male that presented with trochlear palsy without other neurological signs. Brain magnetic resonance imaging (MRI) revealed an acute midbrain infarction. The case report also reviews recent literature and provides a stepwise algorithm for clinicians to approach patients with trochlear palsy. Despite its rarity, clinicians are advised to consider ischaemic stroke as a cause of trochlear palsy even without other neurological deficits. Early MRI should be performed for prompt and proper management.

Abducens Palsy and Anosmia Associated with COVID-19: A Case Report

AIM

To report the case of acute isolated abducens nerve palsy and anosmia in a healthy 69-year-old female following SARS-CoV-2 infection.

METHOD

This is a case report of a previously healthy 69-year-old Caucasian female who presented to the emergency eye centre with a four-day history of binocular, horizontal diplopia eight days after testing positive for SARS-CoV-2 infection. Anosmia was her isolated symptom of COVID-19.

RESULTS

The patient was diagnosed with left abducens nerve palsy. Aetiology was presumed to be post-viral as the patient was not diabetic and had no pre-existing microvascular risk factors. Diplopia resolved within 3.5 weeks. Measurements confirmed complete spontaneous recovery of the abducens palsy within 6 weeks.

CONCLUSION

Cranial nerve palsies may constitute part of the neurological spectrum of COVID-19 disease. This case report aims to raise awareness amongst clinicians of coronavirus-induced neurological symptoms. Research suggests SARS-CoV-2 infection can trigger an aberrant immune response in some individuals, causing inflammatory nerve damage leading to anosmia and neuropathy. This case report supports the hypothesis that direct or indirect virally mediated injuries along the routes of the cranial nerves can cause neuropathy and olfactory dysfunction. The longer latency effects of COVID-19 infection are not well understood. The long-term rehabilitation of patients exposed to COVID-19 is a major public health concern requiring multidisciplinary expertise. This case report highlights the value of the Orthoptist in the diagnosis and care of patients experiencing neuropathy following COVID-19 exposure.

Clinical Significance of MRI Contrast Enhancement of the Oculomotor Nerve in Ischemic Isolated Oculomotor Nerve Palsy

Background and Purpose

Contrast enhancement of the oculomotor nerve in MRI was recently noticed in patients with clinical ischemic isolated oculomotor nerve palsy (iIONP). The opinions about whether this is a sign of inflammation and whether or not to administer steroids vary between doctors. The study aimed to determine the associations between this enhancement and vascular-disease risk factors (VRFs) and inflammatory factors in iIONP patients.

Methods

The study recruited patients who had experienced iIONP during the previous 2 years. They were divided into groups A and B based on whether or not they exhibited an enhanced oculomotor nerve in MRI of the cavernous sinus using thin-section, fat-suppressed, and contrast-enhanced sequences. VRFs, inflammatory factors, and improvement scores were compared between the two groups.

Results

Most (71.1%) of the 45 included iIONP patients had enhanced oculomotor nerves in MRI. VRFs, periorbital pain, elevated C-reactive protein and erythrocyte sedimentation rate, the neutrophil-to-lymphocyte ratio, and the platelet-to-lymphocyte ratio were not significantly associated with the enhancement. Four of the five patients in group A exhibited an elevated cerebrospinal fluid (CSF) IgG synthesis rate. The improvement score of eight patients who received 80 mg of methylprednisolone in addition to the routine therapy was not significantly different from the scores of the other patients (p=0.485).

Conclusions

More than half of the iIONP patients had an enhanced oculomotor nerve in MRI. A few of them also had elevated CSF IgG synthesis rate, but no further evidence for inflammation was found. The administration of steroids seemed to have no benefit other than increasing the blood glucose level.

Acute binocular diplopia: peripheral or central?

Objectives

Acute diplopia is a diagnostic challenge for clinicians, in particular in the emergency department. The most common cause of acute diplopia are ocular motor nerve palsies (OMP). In this prospective study, we focused on identifying the most crucial signs and symptoms for differentiating between peripheral and central OMP.

Methods

We prospectively evaluated 56 non-consecutive patients who presented at our emergency department with acute binocular diplopia (≤ 10 days). The patient history was taken using a standardized questionnaire and patients underwent a neurological, neuro-ophthalmological and neuro-otological examination, including measurement of the subjective visual vertical (SVV), Harms tangent screen test, and cranial MRI.

Results

Forty-six out of 56 patients were diagnosed with an ocular motor cranial nerve palsy (OMP), 21 of peripheral and 23 of central origin; in two patients, the etiology remained unknown. The following features were different in peripheral and central OMP: (1) the presence of vertigo/dizziness was more frequent in central (43.5%) than in peripheral (9.5%) OMP. (2) Central ocular motor signs, such as saccadic smooth pursuit, additional internuclear ophthalmoplegia, skew deviation, and saccade palsies, were also found more frequently in the central than in the peripheral group (86.7% vs. 33.3%). (3) Further, a pathological SVV deviation by monocular testing of the non-affected eye was also more common in central (77.3%) than in peripheral OMP (38.9%). The presence of all three factors has a positive predictive value of 100% (CI 50–100%) for the presence of a central lesion.

Conclusions

In acute diplopia due to central OMP, the most important accompanying symptom is vertigo/dizziness, and the most important clinical signs are central ocular motor disorders (which require examination of the non-paretic eye) and an SVV deviation in the non-paretic eye.

The Incidence and Etiologies of Third Cranial Nerve Palsy in Koreans: A 10-year Nationwide Cohort Study

PURPOSE

This study aimed to determine the incidence, prevalence, and etiologies of third cranial nerve (CN3) palsy in Koreans.

METHODS

Data were collected from the National Health Insurance Service-National Sample Cohort (NHIS-NSC) database of South Korea and analyzed. Incident CN3 palsy subjects in the cohort population were defined as cases occurring after the initial 4-year or longer washout period. The incidence and prevalence were analyzed by sex, age group, and year. The etiologies of CN3 palsy were evaluated using comorbidities.

RESULTS

Of 1,108,253 subjects, 387 patients were newly diagnosed with CN3 palsy between 2006 and 2015. The incidence of CN3 palsy was 3.71 per 100,000 person-years (95% confidence interval, 3.35-4.09). The incidence of CN3 palsy increased with age and accelerated after the age of 60 years. The mean male-to-female incidence ratio was 1.16. The main cause was presumed to be vascular disease (52.7%), followed by idiopathic causes (25.8%), intracranial neoplasm (7.8%), unruptured cerebral aneurysm (5.4%), and trauma (5.2%).

CONCLUSIONS

The incidence of CN3 palsy in Koreans increased with age and peaked between 75 and 79 years. The main cause of CN3 palsy was vascular disease.

Infectious ocular motor neuropathies

PURPOSE OF REVIEW

Describe the range of infectious causes of ocular motor neuropathies, from common presentations to unusual manifestations of diseases less frequently seen in the developed world. Provide information on recent developments in diagnostic testing for pathogens that may cause ocular motor neuropathies.

RECENT FINDINGS

Antigen detection in serum or CSF has improved the diagnosis of cryptococcal disease. Cartridge PCR testing for tuberculosis has increased diagnostic accuracy, though tuberculous meningitis remains difficult to diagnose. Rapid, multiplex PCR and unbiased sequencing allow for diagnosis of a wider range of organisms.

SUMMARY

Infectious ocular motor neuropathies can occur anywhere along the length of cranial nerves III, IV, and VI. Characteristic clinical findings and imaging can be used to localize infections. Infectious causes may have characteristic clinical, laboratory, or imaging findings, but must still be carefully separated from inflammatory or neoplastic conditions.

The incidence and etiology of sixth cranial nerve palsy in Koreans: A 10-year nationwide cohort study

We aimed to investigate the incidence, prevalence, and etiology of sixth cranial nerve (CN6) palsy in the general Korean population. The nationally representative dataset of the Korea National Health Insurance Service–National Sample Cohort from 2006 through 2015 was analyzed. The incidence and prevalence of CN6 palsy were estimated in the cohort population, confirming that incident cases of CN6 palsy involved a preceding disease-free period of ≥4 years. The etiologies of CN6 palsy were presumed using comorbidity conditions. Among the 1,108,256 cohort subjects, CN6 palsy developed in 486 patients during the 10-year follow-up. The overall incidence of CN6 palsy was estimated to be 4.66 per 100,000 person-years (95% confidence interval [CI], 4.26–5.08) in the general population. This incidence increased with age, accelerating after 60 years of age and peaking at 70–74 years of age. The mean male-to-female incidence ratio was estimated as 1.41 in the whole population, and the incidence and prevalence of CN6 palsy showed an increasing trend over time in the study period. Surgical incidence for CN6 palsy was only 0.19 per 100,000 person-years (95% CI, 0.12–0.29). The etiologies were presumed to be vascular (56.6%), idiopathic (27.2%), neoplastic (5.6%), and traumatic (4.9%). In conclusion, the incidence of CN6 palsy increases with age, peaking at around 70 years, and shows a mild male predominance in Koreans.

Acute onset binocular diplopia: a retrospective observational study of 100 consecutive cases managed at a tertiary eye centre in Saudi Arabia

OBJECTIVE

To evaluate the demography, aetiology and clinical course of acute onset binocular diplopia (AOBD) in patients presented as emergency and managed at the neuroophthalmology clinic of a tertiary eye care centre in Saudi Arabia.

PATIENTS AND METHODS

A retrospective review of the medical records of 100 consecutive patients who attended the emergency department of Dhahran Eye Specialist Hospital with isolated, AOBD. The exclusion criteria were: (a) monocular diplopia, (b) binocular diplopia accompanied with neurological deficits other than ocular muscles dysfunction and (c) thyroid eye disease. All patients were followed until resolution of the diplopia or onward referral to another specialty for further management.

RESULTS

Male:female ratio was 2:1. Median age of the cohort was 56 years (range 18-90 years). Associated nerve palsy included: abducens nerve (n = 57 patients), oculomotor (n = 32 patients) and trochlear nerve (n = 3 patients). Microvascular ischaemia and ocular myasthenia gravis were two most common pathogenic mechanisms. AOBD resolved spontaneously in 98% of patients.

CONCLUSION

AOBD, though an alarming and distressing condition, carries reassuringly good prognosis in majority of patients. High risk factors for vascular disease in Middle-Eastern population are reflected in microvascular aetiology as the major cause.