Ophthalmoscopy in the 21st century: The 2017 H. Houston Merritt Lecture

Although the usefulness of viewing the ocular fundus is well-recognized, ophthalmoscopy is infrequently and poorly performed by most nonophthalmologist physicians, including neurologists. Barriers to the practice of ophthalmoscopy by nonophthalmologists include not only the technical difficulty related to direct ophthalmoscopy, but also lack of adequate training and discouragement by preceptors. Recent studies have shown that digital retinal fundus photographs with electronic transmission and remote interpretation of images by an ophthalmologist are an efficient and reliable way to allow examination of the ocular fundus in patients with systemic disorders such as diabetes mellitus. Ocular fundus photographs obtained without pharmacologic dilation of the pupil using nonmydriatic fundus cameras could be of great value in emergency departments (EDs) and neurologic settings. The Fundus Photography vs Ophthalmoscopy Trial Outcomes in the Emergency Department (FOTO-ED) study showed that ED providers consistently failed to correctly identify relevant ocular funduscopic findings using the direct ophthalmoscope, and that nonmydriatic fundus photography was an effective alternate way of providing access to the ocular fundus in the ED. Extrapolating these results to headache clinics, outpatient neurology clinics, and adult and pediatric primary care settings seems self-evident. As technology advances, nonmydriatic ocular fundus imaging systems will be of higher quality and more portable and affordable, thereby circumventing the need to master the use of the ophthalmoscope. Visualizing the ocular fundus is more important than the method used. Ocular fundus photography facilitates nonophthalmologists' performance of this essential part of the physical examination, thus helping to reestablish the value of doing so.

Inherited eye-related disorders due to mitochondrial dysfunction

Genetic disorders due to mitochondrial dysfunction are not uncommon and the majority of these patients will have eye-related manifestations, including visual loss from the optic nerve and retinal disease, visual field loss from retrochiasmal visual pathway damage, and ptosis and ocular dysmotility from extraocular muscle involvement. Defects in both the nuclear and mitochondrial genomes cause mitochondrial dysfunction via several mechanisms, including impaired mitochondrial energy production, oxidative stress, mitochondrial DNA instability, abnormalities in the regulation of mitochondrial dynamics and mitochondrial quality control, and disturbed cellular interorganellar communication. Advances in our understanding of the molecular genetic basis of mitochondrial disease have not only improved genetic diagnosis, but they have provided important insights into the pathophysiologic basis of these disorders and potential therapeutic targets. In parallel, more sophisticated techniques for genetic manipulation are facilitating the development of animal and in vitro models that should prove powerful and versatile tools for disease modelling and therapeutic experimentation. Effective therapies for mitochondrial disorders are beginning to translate from bench to bedside along the paths of neuroprotection, gene replacement and stem cell-based regenerative paradigms. Additionally, preventing the transmission of pathogenic mtDNA mutations from mother to child is now a reality with in vitro fertilization mitochondrial replacement techniques.

Cerebrospinal fluid total protein in idiopathic intracranial hypertension

OBJECTIVE

To evaluate the relationship between CSF total protein concentration (CSF protein) and CSF opening pressure in idiopathic intracranial hypertension (IIH), and to explore the association of age, gender, race, BMI, and Humphrey visual field mean deviation (HVF MD) with CSF total protein.

METHODS

The medical records of all IIH patients seen between 1989 and 2016 at one institution were systematically reviewed for demographics, CSF opening pressure, CSF contents, and HVF MD (at initial evaluation and most recent follow-up). Linear regression of CSF protein on CSF opening pressure was performed also considering BMI, age, gender, race, HVF MD, and year of lumbar puncture.

RESULTS

We included 266 IIH patients (13 pre-pubertal children, 35 post-pubertal children, 218 adults). There was a negative linear association between CSF opening pressure and CSF protein: CSF protein decreased by 0.18mg/dL for each 1cm H₂O increase in CSF opening pressure (p<0.001). After controlling for CSF opening pressure, mean CSF protein was 4.1mg/dL higher in white patients than in black patients (p<0.001). Multivariable analysis found that CSF opening pressure (p=0.007), white race (p<0.001), and HVF MD (most recent follow-up, worst eye, p=0.05) remained independently associated with CSF protein controlling for year of lumbar puncture and age.

CONCLUSIONS

There was a negative association between CSF protein and CSF opening pressure. After controlling for CSF opening pressure, CSF protein was higher in white patients and unaffected by age, gender, or BMI. Our findings help clarify inconsistent results of prior studies, but do not really help clarify IIH pathophysiology.

Update on the Management of Central Retinal Artery Occlusion

Central retinal artery occlusion (CRAO) is caused by partial or complete occlusion of the central retinal artery, most commonly by an embolus from the ipsilateral carotid artery, aortic arch, or heart, and is the ocular equivalent of an acute cerebral ischemic event. The risk factors for a CRAO and acute cerebral ischemia are very similar, if not identical. Because no current therapeutic intervention has been shown to improve visual outcomes compared with the natural history of CRAO, management of CRAO should be focused on secondary prevention of vascular events, such as cerebral ischemia, myocardial infarction, and cardiovascular death.

Diagnosis and clinical features of common optic neuropathies

Disorders of the optic nerves (optic neuropathies) are some of the most common causes of visual loss, and can present in isolation or with associated neurological or systemic symptoms and signs. Several optic neuropathies-especially inflammatory optic neuropathies-are associated with neurological disorders and thus are often diagnosed and treated by neurologists. The mechanisms underlying optic neuropathies are diverse and typically manifest with decreased visual acuity, altered colour vision, and abnormal visual field in the affected eye. Diagnosis is made on the basis of clinical history and clinical examination, of which several aspects are particularly important, including the mode of onset of visual loss, the presence of pain with eye movements, the visual acuity, and the retention of colour vision. Advances in optic nerve imaging-particularly retinal digital photography, optical coherence tomography, and MRI techniques-have revolutionised the diagnosis and follow-up of patients with an optic neuropathy. Furthermore, improvement and generalisation of some ancillary tests, such as diagnostic antibodies for neuromyelitis optica, allows better phenotyping of the heterogeneous inflammatory optic neuropathies.

Imaging Features of Idiopathic Intracranial Hypertension in Children

Magnetic resonance imaging (MRI) signs of elevated intracranial pressure and idiopathic intracranial hypertension have been well characterized in adults but not in children. The MRIs of 50 children with idiopathic intracranial hypertension and 46 adults with idiopathic intracranial hypertension were reviewed for optic nerve head protrusion, optic nerve head enhancement, posterior scleral flattening, increased perioptic cerebrospinal fluid, optic nerve tortuosity, empty or partially empty sella, tonsillar herniation, enlargement of Meckel's cave meningoceles, and transverse venous sinus stenosis(TSS). Compared to adolescents (11-17 years, n = 40) and adults (>17 years, n = 46), prepubescent children (<11 years, n = 10) had lower frequencies of scleral flattening (50% vs 89% and 85%, P = .02), increased perioptic cerebrospinal fluid (60% vs 84% and 89%, P = .08), optic nerve tortuosity (20% vs 46% and 59%, P = .07), empty or partially empty sella (56% vs 78% and 93%, P = .007), and TSS (67% vs 93% and 96%, P = .04). Children with idiopathic intracranial hypertension have similar MRI findings as adults, but they are less frequent in prepubescent children.

Third, Fourth, and Sixth Cranial Nerve Palsies in Pituitary Apoplexy

BACKGROUND

Pituitary apoplexy (PA) often presents with acute headache and neuro-ophthalmic manifestations, including ocular motility dysfunction (OMD) from cranial nerve palsies (CNPs). Our goal was to describe the epidemiology and outcomes of OMD in a large, single-center series of patients with PA.

METHODS

We conducted a retrospective chart review of all patients with PA seen in our pituitary center between January 1995 and December 2012. Presenting neuro-ophthalmic, endocrine, and radiologic data, as well as neuro-ophthalmology follow-up data, were collected.

RESULTS

We identified 235 patients with PA, 59 of whom (25%) had OMD. Twenty-seven of those 59 patients underwent neuro-ophthalmic evaluation. Preoperatively, 23 of these 27 patients had unilateral OMD, 18 (78%) with a single CNP and 5 (22%) with multiple CNPs. Bilateral OMD was present in 4 of the 27 patients. Postoperatively, 24 of the 27 patients with OMD had follow-up (median duration, 7 months; interquartile range [IQR], 3-17 months). At the last postoperative follow-up, 7 of these 24 patients (29%) had OMD (5 unilateral, 2 bilateral). OMD resolved in 3 of the 24 patients (12%) within 1 month, in 13 of 21 patients (62%) within 6 months (3 lost to follow-up), and in 17 of 19 patients (89%) within 1 year (2 lost to follow-up). Surgery was performed at ≤14 days after presentation in 16 of 18 (89%) resolved cases and in 4 of 6 (67%) unresolved cases. Patients with OMD were more likely than those without OMD to have larger tumors (2.6 vs. 2.0 cm; P < 0.001), panhypopituitarism (31% vs. 14%; P = 0.005), and necrosis (58% vs. 37%; P = 0.03).

CONCLUSIONS

OMD from CNPs is common in PA, occurring in one-quarter of patients, and is frequently associated with certain radiologic, endocrinologic, and pathological features. The prognosis is excellent, with 90% of cases of OMD resolving by 1 year after early pituitary surgery.

Pitfalls in the Use of Stereoacuity in the Diagnosis of Nonorganic Visual Loss

PURPOSE

The Titmus Stereotest (Stereo Optical Co., Inc., Chicago, IL) has been used to estimate visual acuity (VA) in the evaluation of nonorganic visual loss. Previous predictions were derived from optical degradation of VA in normal subjects and may not account for the variability seen in patients with neuro-ophthalmic pathologies included in the differential diagnosis of nonorganic visual loss. The purpose of this study was to evaluate the relationship between Titmus stereoacuity and minimal VA based on a real-world testing environment.

DESIGN

Cross-sectional observational study.

PARTICIPANTS

All patients treated at the authors' neuro-ophthalmology service between April 25, 2014, and July 31, 2014.

METHODS

All subjects underwent routine neuro-ophthalmic examination, including Titmus stereoacuity measurements. A compound Bayesian logit-lognormal model accounting for heteroscedasticity was used to determine 95% and 99% prediction intervals of the worse eye's near VA based on stereoacuity. Logarithm of the minimum angle of resolution VA and log stereoacuity were analyzed.

MAIN OUTCOME MEASURES

Titmus stereoacuity and worse eye VA.

RESULTS

Of 561 patients, 364 subjects 11 to 91 years of age were included. Titmus stereoacuity was associated positively with VA: 9 circles correct (40 seconds of arc) indicated VA of at least 20/40 with 95% confidence and VA of at least 20/79 with 99% confidence; 6 circles correct (80 seconds of arc) indicated VA of at least 20/62 and 20/180, respectively; and 4 circles correct (140 seconds of arc) indicated VA of at least 20/110 and 20/570, respectively.

CONCLUSIONS

When fully accounting for individual variation and the full spectrum of neuro-ophthalmic diseases affecting VA, stereoacuity remains associated with VA, but previous commonly used VA estimates based on stereoacuity overestimated VA. Our results more accurately predict minimum VA from Titmus stereoacuity and should be used preferentially when evaluating patients with suspected nonorganic visual loss. We demonstrated that Titmus stereoacuity cannot definitively establish normal VA, and therefore can suggest, but not fully establish, the diagnosis of nonorganic visual loss.

Overdiagnosis of idiopathic intracranial hypertension

OBJECTIVE

To delineate the factors contributing to overdiagnosis of idiopathic intracranial hypertension (IIH) among patients seen in one neuro-ophthalmology service at a tertiary center.

METHODS

We retrospectively reviewed new patients referred with a working diagnosis of IIH over 8 months. The Diagnosis Error Evaluation and Research taxonomy tool was applied to cases referred with a diagnosis of IIH and a discrepant final diagnosis.

RESULTS

Of 1,249 patients, 165 (13.2%) were referred either with a preexisting diagnosis of IIH or to rule out IIH. Of the 86/165 patients (52.1%) with a preexisting diagnosis of IIH, 34/86 (39.5%) did not have IIH. The most common diagnostic error was inaccurate ophthalmoscopic examination in headache patients. Of 34 patients misdiagnosed as having IIH, 27 (27/34 [79.4%]; 27/86 [31.4%]) had at least one lumbar puncture, 29 (29/34 [85.3%]; 29/86 [33.7%]) had a brain MRI, and 8 (8/34 [23.5%]; 8/86 [9.3%]) had a magnetic resonance/CT venogram. Twenty-six had received medical treatment, 1 had a lumbar drain, and 4 were referred for surgery. In 8 patients (8/34 [23.5%]; 8/86 [9.3%]), an alternative diagnosis requiring further evaluation was identified.

CONCLUSIONS

Diagnostic errors resulted in overdiagnosis of IIH in 39.5% of patients referred for presumed IIH, and prompted unnecessary tests, invasive procedures, and missed diagnoses. The most common errors were inaccurate ophthalmoscopic examination in headache patients and thinking biases, reinforcing the need for rapid access to specialists with experience in diagnosing optic nerve disorders. Indeed, the high prevalence of primary benign headaches and obesity in young women often leads to costly and invasive evaluations for presumed IIH.

Nonmydriatic ocular fundus photography in neurologic emergencies

IMPORTANCE

The ocular fundus examination is infrequently and poorly performed in clinical settings, placing patients at risk for missed and delayed diagnosis of vision- and life-threatening neurologic disease.

OBJECTIVES

To review the importance of ocular fundus examination, the limitations of direct ophthalmoscopy, and the relative merits of nonmydriatic ocular fundus photography in emergency neurologic diagnosis.

EVIDENCE REVIEW

PubMed queries were reviewed for articles of relevance to this review. Queries included relevant combinations of the search terms ophthalmoscopy, nonmydriatic, neurology, and emergency, including variant spellings and endings.

FINDINGS

Nonmydriatic ocular fundus photography is more sensitive than direct ophthalmoscopy in several settings. It can be feasibly performed in emergency departments and has substantial promise in improving neurologic diagnosis, particularly headache and cerebrovascular disease.

CONCLUSIONS AND RELEVANCE

Nonmydriatic ocular fundus photography has notable advantages over direct ophthalmoscopy that likely outweigh its associated costs. More widespread deployment and integration into neurologic practice is expected to improve diagnosis and patient outcomes.

Ocular fundus photography of patients with focal neurologic deficits in an emergency department

OBJECTIVES

We evaluated the frequency and predictive value of ocular fundus abnormalities among patients who presented to the emergency department (ED) with focal neurologic deficits to determine the utility of these findings in the evaluation of patients with suspected TIA and stroke.

METHODS

In this cross-sectional pilot study, ocular fundus photographs were obtained using a nonmydriatic fundus camera. Demographic, neuroimaging, and ABCD(2) score components were collected. Photographs were reviewed for retinal microvascular abnormalities. The results were analyzed using univariate statistics and logistic regression modeling.

RESULTS

Two hundred fifty-seven patients presented to the ED with focal neurologic deficits, of whom 81 patients (32%) had cerebrovascular disease (CVD) and 144 (56%; 95% confidence interval: 50%-62%) had retinal microvascular abnormalities. Focal and general arteriolar narrowing increased the odds of clinically diagnosed CVD by 5.5 and 2.6 times, respectively, after controlling for the ABCD(2) score and diffusion-weighted imaging. These fundus findings also significantly differentiated TIA from non-CVD, even after controlling for the ABCD(2) score.

CONCLUSIONS

Focal and general arteriolar narrowing were independent predictors of CVD overall, and TIA alone, even after controlling for the ABCD(2) score and diffusion-weighted imaging lesions. The inclusion of nonmydriatic ocular fundus photographs in the evaluation of patients presenting to the ED with focal neurologic deficits may assist in the differentiation of stroke and TIA from other causes of focal neurologic deficits.

The demise of direct ophthalmoscopy: A modern clinical challenge

Ocular funduscopy appears to be a dying art. Physicians and medical students alike lack confidence in the use of an ophthalmoscope. As a result, few clinicians perform ophthalmoscopy, and many who do are unable to reliably detect abnormalities of the ocular fundus. Approaches to remediation in undergraduate medical education have included simulators, longitudinal skill reinforcement, Web-based teaching, and other techniques. Preservation of the ophthalmoscopic art has been hindered by technical difficulty, waning enthusiasm for ophthalmoscopy, and even discouragement from preceptors in medical education. Ocular fundus photography may serve a role in medical education to help improve student confidence in interpretation of ocular fundus findings and improve awareness of the importance of examination of the ocular fundus. Because neurology clerkships and clinical practices remain an important forum for honing ocular funduscopy skills, the neurologist should be familiar with novel alternative techniques that facilitate examination of the ocular fundus.

Predictors of Good Motor and Sensory Outcomes Following Strabismus Surgery for Patients with Third Nerve Palsies

Strabismus from third nerve palsy (3NP) is difficult to treat. Our goal was to explore factors associated with successful surgical outcomes in 3NP. Institutional records of all adult patients (>18 years) from 1988 to 2012 with 3NP who underwent strabismus surgery or botulinum toxin injections were retrospectively reviewed. Success was defined as absence of diplopia, vertical deviation ≤2 prism dioptres (PD), and horizontal deviation ≤10 PD. Fifty-six patients from four surgeons were included. Thirty (54%) were female; mean age was 48 (range: 20-80). Forty-four (79%) had unilateral 3NP; 9 (16%) had other ocular motor nerve palsies. 3NP were complete in 24 (43%). Underlying aetiology was idiopathic/microvascular in 5 (9%), traumatic in 13 (23%), neoplastic in 12 (21%), aneurysmal in 10 (18%), and other central nervous system related in 16 (29%). Trauma was associated more frequently with aberrant regeneration than other aetiologies: 9/13 (69%) versus 4/43 (9%) (p < 0.01). Ten patients (18%) had >1 surgery. Surgical success was achieved in 28/56 (50%). Success rate was unaffected by aetiology, degree of palsy, pupillary involvement, presence of aberrant regeneration, or number of other cranial nerves involved. However, adjustable sutures were used in 27 patients (48%), and there was a trend toward higher success rates when adjustable versus nonadjustable sutures were used (63% versus 38%; p = 0.06). Unlike with sixth nerve palsies, the aetiology and degree of 3NP does not appear to affect the success rates or number of procedures performed. Strabismus surgeries for 3NP with adjustable sutures may be associated with better outcomes.

Functional and Motor Outcomes of Strabismus Surgery for Chronic Isolated Adult Sixth Nerve Palsy

Abducens nerve palsy is the most common acquired ocular motor nerve palsy in adults. Chronic cases of abducens palsy often require surgical intervention to relieve disabling diplopia. The goal of this study was to identify factors associated with surgical outcomes in isolated abducens palsy. Medical records of all adult patients from 1988 to 2012 with abducens palsies who underwent strabismus procedures were retrospectively reviewed. Motor alignment, extraocular motility, and sensory outcomes were recorded. Success was defined as absence of diplopia without prisms or face turn, vertical deviation ≤2 prism dioptres (PD), and horizontal deviation ≤10 PD. Eighty-one patients (age range: 20-86 years) met inclusion criteria. Success was achieved in 58% of patients. Final success rates for abducens palsy were 50% for neoplastic, 59% traumatic, 57% for microvascular/unknown, and 67% for other central nervous system causes (p > 0.05). Patients with an underlying neoplastic or traumatic aetiology required more than one strabismus procedure more often than those with microvascular/idiopathic or other central nervous system causes (48% vs. 24%; p = 0.03). For complete abducens palsies, patients who underwent Hummelsheim-type procedures had a higher success rate than those who underwent a full-tendon vertical rectus muscle transposition. (78% versus 35%; p = 0.049). Success rates for strabismus procedures in patients with abducens palsies are similar across all aetiologies. Frequency of re-operation is higher among those patients with neoplastic or traumatic aetiologies for their abducens palsies. Hummelsheim-type procedures have a higher success rate for complete abducens palsies than full-tendon vertical rectus transpositions.

A prospective photographic study of the ocular fundus in obstructive sleep apnea

BACKGROUND

The prevalence of optic nerve and retinal vascular changes within the obstructive sleep apnea (OSA) population are not well-known, although it has been postulated that optic nerve ischemic changes and findings related to an elevated intracranial pressure may be more common in OSA patients. We prospectively evaluated the ocular fundus in unselected patients undergoing overnight diagnostic polysomnography (PSG).

METHODS

Demographic data, medical/ocular history, and nonmydriatic fundus photographs were prospectively collected in patients undergoing PSG at our institution and reviewed for the presence of optic disc edema for which our study was appropriately powered a priori. Retinal vascular changes were also evaluated. OSA was defined using the measures of both sleep-disordered breathing and hypoxia.

RESULTS

Of 250 patients evaluated in the sleep center, fundus photographs were performed on 215 patients, among whom 127 patients (59%) had an apnea/hypopnea index (AHI) ≥ 15 events per hour, including 36 with severe OSA. Those with AHI <15 served as the comparison group. None of the patients had optic disc edema (95% confidence interval [CI]: 0%-3%). There was no difference in rates of glaucomatous appearance or pallor of the optic disc among the groups. Retinal arteriolar changes were more common in severe OSA patients (odds ratio: 1.09 per 5 unit increase in AHI; 95% CI, 1.02-1.16; P = 0.01), even after controlling for mean arterial blood pressure.

CONCLUSIONS

We did not find an increased prevalence of optic disc edema or other optic neuropathies in our OSA population. However, retinal vascular changes were more common in patients with severe OSA, independent of blood pressure.