Correlation Between Optic Disc Peripapillary Capillary Network and Papilledema Grading in Patients With Idiopathic Intracranial Hypertension: A Study of Optical Coherence Tomography Angiography.

BACKGROUND: The continued increase in idiopathic intracranial hypertension (IIH) prevalence has many implications for societal health care. Its potential vision-threatening consequences make ophthalmologists key players in its diagnosis and management. Newer technology such as optical coherence tomography angiography (OCT-A) enables evaluation of the branching complexity of the peripapillary capillary plexus, a region where accurate imaging via fluorescein angiography was previously limited. METHODS: A cross-sectional, observational study of 23 (46 eyes) consecutive patients with IIH. Peripapillary total vasculature was recorded using commercial OCT-A en face vessel density mapping. In addition, OCT-A blood flow slab was compared with papilledema grading. OCT-A images were analyzed using a customized image analysis protocol using ImageJ software (v1.51w) and Photoshop software (Adobe Systems, CA). SPSS software version 25 was used for statistical analysis (SPSS Inc, IBM, Chicago, IL). RESULTS: Skeletonized vessel density peripapillary capillary plexus was significantly associated with Frisen papilledema grades, OCT retinal nerve fiber layer (RNFL), and macular ganglion cell layer (GCL) thickness with a P < 0.001, P = 0.022, and P = 0.006, respectively. Every point increase in grade was correlated with a decrease of 9.1 pixels/mm2 in vessel density (R = 0.512, ß = -0.115 ± 0.029; P < 0.001). Increased papilledema was correlated with an increased retinal blood flow percentage (R = 0.300, ß = 2.114 ± 1.013; P < 0.05) and decreased choroidal blood flow (CBF) percentage (R = 0.300, ß = 2.114 ± 1.013; P < 0.05). Every point increase in grade was correlated with a decrease in CBF by 47.4%, as calculated using a linear best-fit line inclusive for all of the data points. CONCLUSIONS: OCT-A allows for effective visualization and quantification of the peripapillary retinal vasculature. Our results demonstrate a correlation between skeletonized peripapillary density and papilledema grading, OCT RNFL thickness, and GCL thickness. In addition, we show a significant negative correlation between CBF and papilledema grading. These changes provide key findings regarding the pathophysiology of optic neuropathy in papilledema and highlight the potential of OCT-A as a diagnostic tool for papilledema and a clinical marker for detecting early optic nerve damage.

Reversible retinoschisis following high voltage electrical injury evaluated with optical coherence tomography and electrophysiology.

PURPOSE: To report a carefully studied case of high voltage electrical injury of the retina and optic nerve with anatomically reversible retinoschisis. METHODS: Observational case report. RESULTS: A 22 year old power company worker was electrocuted with 12,000 V, with his left forehead being the exit point of the current. After regaining consciousness he reported decreased vision with both eyes. He was extensively tested with optical coherence tomography (OCT) and angiography (OCT-A), fundus photography, fluorescein angiography (FA), multifocal electroretinography (mfERG), full field electroretinography (ffERG), visual evoked potentials (VEP), and Goldmann-type Octopus automated perimetry in addition to careful clinical examinations. Our investigations revealed severe visual field constriction in both eyes, severe coagulative damage leading to inner and outer retinal atrophy, subretinal fluid collection, retinoschisis cavities, and papillitis. Initially he was treated with 100 mg prednisone per day for one week and 250 mg acetazolamide per day which was continued for 3 months. Over time the OCT signs of retinoschisis resolved but visual acuity and visual field improvement did not occur. CONCLUSION: Resolution of retinoschisis cavities following electrical damage does not necessarily lead to improvement in visual function due to the many accompanying structural injuries.

Unusual Cause of Horner Syndrome 13 Years After In Situ Ductal Carcinoma.

Horner syndrome can be caused by a wide range of pathologies along the sympathetic nerve chain, from the hypothalamus to the orbit. Imaging workup of Horner syndrome is necessary given the potential for deadly lesions, especially in a patient with a previous cancer history. The authors report a case of a woman who presented with a preganglionic Horner syndrome secondary to vertebral metastasis from previously diagnosed breast cancer that involved the neural foramina at T1 and T2.

Use of Ocular Coherence Tomography in Children With Idiopathic Intracranial Hypertension-A Single-Center Experience.

BACKGROUND: Idiopathic intracranial hypertension is a disorder characterized by elevated intracranial pressure without an identifiable etiology. Detection of papilledema may be challenging and leads to diagnostic uncertainty in evaluating a child for possible idiopathic intracranial hypertension. Ocular coherence tomography has the potential to add accuracy to the diagnosis of idiopathic intracranial hypertension. The goal of the present study was to determine if there was a relationship between severity of papilledema (as determined by direct ophthalmoscopy and confirmed by fundus photography) and measures of ocular coherence tomography in a pediatric population with idiopathic intracranial hypertension. METHODS: Thirteen pediatric patients were recruited prospectively after diagnosis of either definitive idiopathic intracranial hypertension (with papilledema) or possible idiopathic intracranial hypertension (without papilledema) at Children's Hospital of Michigan over a period of one year. Clinical data and results of initial ocular coherence tomography and visual field testing were collected and statistically analyzed. RESULTS: The Frisén scale of papilledema significantly correlated with average retinal nerve fiber layer thickness of each eye (r = 0.633, P = 0.02 in right eye and r = 0.868, P = 0.001 in left eye). The retinal nerve fiber layer thickness (mean ± SD) was significantly higher in the definitive group than in the possible group (189 ± 65 µm vs 104 ± 10 µm in right eye, 165 ± 42 µm vs 106 ± 9 µm in left eye, P < 0.01 in both eyes). CONCLUSIONS: Ocular coherence tomography may be used as a supplementary method to aid in the reliable detection of papilledema in evaluating a child for idiopathic intracranial hypertension.

A comparative study of resident performance on standardized training examinations and the american board of ophthalmology written examination.

PURPOSE: To investigate the relationships between ophthalmology resident performance on the United States Medical Licensing Examination (USMLE), the Ophthalmic Knowledge Assessment Program (OKAP) exam and the American Board of Ophthalmology written qualifying examination (ABO-WQE). DESIGN: Cohort study. PARTICIPANTS: We included 76 residents from 15 consecutive training classes (1991-2006) at 1 ophthalmologic residency training program. METHODS: Numeric scores on the USMLE Step 1 and OKAP examinations during the 3 years of residency, and first attempt pass rate on the ABO-WQE were recorded for 76 residents. Age and gender were also noted. Spearman's rank correlations and univariate and multivariate logistic analyses were performed to determine relevant associations. MAIN OUTCOME MEASURES: First-time attempt pass rate on the ABO-WQE and/or successful completion of the ABO-WQE within 3 years of graduation from the residency program. RESULTS: The ABO-WQE first-attempt pass rate was 72.6%, consistent with the national average. Resident USMLE scores were not significantly associated with ABO-WQE performance. The ABO-WQE pass rate was significantly associated with OKAP examination scores during the 3 residency years (year 1: odds ratio [OR], 8.85 and 95% confidence interval [CI] 1.82-42.79; year 2: OR, 5.28 and 95% CI, 1.15-25.27; year 3: OR, 11.08 and 95% CI, 1.86-68.96). Passing the OKAP examinations in all 3 years during residency training was associated with 5.43-fold increased odds of passing the ABO-WQE and failing all 3 OKAP examinations was associated with >9-fold lower odds of passing the ABO-WQE on the first attempt. CONCLUSIONS: Our results suggest that OKAP examination performance is a predictor of a resident's success in passing the ABO-WQE on the first attempt, as well as within 3 years of graduation from an ophthalmologic training program. Awareness of this association may permit identification of residents at risk for failing the ABO-WQE and encourage educational remediation to prevent this failure.

Crossover trial of gabapentin and memantine as treatment for acquired nystagmus.

We conducted a masked, crossover, therapeutic trial of gabapentin (1,200mg/day) versus memantine (40 mg/day) for acquired nystagmus in 10 patients (aged 28-61 years; 7 female; 3 multiple sclerosis [MS]; 6 post-stroke; 1 post-traumatic). Nystagmus was pendular in 6 patients (4 oculopalatal tremor; 2 MS) and jerk upbeat, hemi-seesaw, torsional, or upbeat-diagonal in each of the others. For the group, both drugs reduced median eye speed (p < 0.001), gabapentin by 32.8% and memantine by 27.8%, and improved visual acuity (p < 0.05). Each patient improved with 1 or both drugs. Side effects included unsteadiness with gabapentin and lethargy with memantine. Both drugs should be considered as treatment for acquired forms of nystagmus.

Two hypothetical nystagmus procedures: augmented tenotomy and reattachment and augmented tendon suture (Sans tenotomy).

PURPOSE: To review the hypothetical mechanism and therapeutic benefits of the four-muscle tenotomy and reattachment (T&R) procedure using knowledge accrued over the 10 years since its proposal; to describe an augmented tendon suture (ATS) technique to improve the procedure based on one of the originally suggested alternative methods (mechanical); and to hypothesize a new ATS procedure to achieve the same therapeutic benefits without extraocular muscle tenotomy or reattachment to the globe. METHODS: Standard surgical methods were used. RESULTS: The T&R procedure damps and improves infantile nystagmus syndrome (INS) waveforms, improves eXtended Nystagmus Acuity Function (NAFX) values, broadens the NAFX peak versus gaze angle, and damps slow eye movements but not saccades. The T&R procedure also damps acquired pendular and downbeat nystagmus, decreasing the patients' oscillopsia, and lowers the target acquisition time in INS. CONCLUSION: The T&R procedure directly affects only the enthesis of the tendon; there is idiosyncratic variation in the distribution of afferent fibers in the tendons. The ATS technique consists of placing several additional sutures in the tendon proximal to the tenotomy. Based on the hypothetical proprioceptive mechanism for the beneficial effects of the T&R procedure, the authors hypothesize that the ATS technique will maximize the therapeutic benefits and that an ATS procedure, using only tendon sutures without tenotomy, will duplicate the therapeutic effects of T&R. Eliminating the tenotomy component results in a simpler procedure more suitable for single-session, multi-muscle surgery that may be required for improving the waveforms of multiplanar nystagmus and less prone to cause complications.

Two patients with spinocerebellar ataxia type 7 presenting with profound binocular visual loss yet minimal ophthalmoscopic findings.

Two patients with genetically confirmed spinocerebellar ataxia type 7 (SCA7) presented with progressive visual loss. Examination disclosed substantial visual acuity loss, central scotomas, and marked dyschromatopsia. Ophthalmoscopic abnormalities were subtle, with only mild retinal artery attenuation and minimal foveal region pigmentary abnormalities. Both patients had slow saccades and partially limited ductions, although neither reported diplopia. One patient had obvious extremity and gait ataxia, but the other had only an unsteady tandem gait. Results of electroretinography (ERG) were abnormal in both patients. These cases illustrate that SCA7 may present with profound visual loss yet minimal ophthalmoscopic findings and sometimes minimal ataxia. The clues to diagnosis are the abnormal color vision, retinal artery attenuation, abnormal eye movements, and a family history of similar manifestations, which may have gone undiagnosed. Full-field or multifocal ERG will always disclose photoreceptor dysfunction. Genetic testing is now available to confirm the diagnosis.

Upbeat-torsional nystagmus and contralateral fourth-nerve palsy due to unilateral dorsal ponto mesencephalic lesion.

The central projections of the anterior semicircular canals are thought to be conveyed from the vestibular nuclei to the oculomotor nuclei in the midbrain by three distinct brainstem pathways: the medial longitudinal fasciculus, crossing ventral tegmental tract, and brachium conjunctivum. There is controversy as to whether upbeat nystagmus could result from lesions involving each of these pathways. We report a 52-year-old man who presented with a contralesional fourth-nerve palsy and primary-position upbeat-torsional nystagmus due to a small unilateral dorsal pontomesencephalic lymphomatous deposit. It is postulated that the upbeat-torsional nystagmus was caused by involvement of the brachium conjunctivum, which lies adjacent to the fourth-nerve fascicles at the dorsal pontomesencephalic junction, but involvement of the crossing ventral tegmental tract cannot be excluded. These observations suggest that, in humans, excitatory upward-torsional eye movement signals from the anterior semicircular canals could be partly conveyed to the midbrain by the brachium conjunctivum.

Clinical course and prognosis of trochlear nerve schwannomas.

PURPOSE: To delineate the disease course and prognosis of patients with mass lesions of the fourth nerve presumed to be schwannomas. DESIGN: Nonrandomized retrospective case series. PARTICIPANTS: Thirty-seven consecutive cases of presumed trochlear nerve schwannoma from 9 tertiary university neuro-ophthalmology centers. METHODS: Cases were collected, and their clinical characteristics on presentation and follow-up are described. Inclusion criteria were brain magnetic resonance imaging (MRI) with a lesion suggestive of a schwannoma along the course of the fourth nerve. Exclusion criteria were other causes of fourth nerve palsy, such as congenital, traumatic or microvascular; normal (or lack of) initial brain MRI; lack of adequate clinical information; and disappearance of the lesion on subsequent follow-up brain MRI. MAIN OUTCOME MEASURES: Demographics of patients, presence of neurofibromatosis, symptoms on presentation, vertical deviation, lesion size (on presentation and follow-up), length of follow-up, and outcomes of treatment for lesions or diplopia. RESULTS: Seven patients were excluded and of the 30 patients included in our series, patients were predominantly male (77%) with a mean age of 51 years (range 9-102 years). In contrast with prior case reports, almost all of our cases had a fourth nerve palsy on presentation (29/30), often isolated. Mean follow-up was 3.1 years (range 0.2 months to 11.1 years). There was no significant difference between initial and follow-up lesion size (4.4 vs. 5 mm) for patients who did not receive treatment of lesions (P = 0.36). Only 3 patients underwent neurosurgical resection and an additional patient received gamma-knife radiotherapy. The majority of patients (24/30) did not pursue strabismus surgery for vertical diplopia. CONCLUSIONS: Patients with isolated fourth nerve palsy and small lesions of the fourth nerve have a good prognosis and should be followed with serial MRI scans without neurosurgical intervention unless they develop signs of brain stem compression. Most patients with diplopia and benign fourth nerve lesions typical of trochlear nerve schwannoma can adapt with either prism spectacles or no treatment at all, although strabismus surgery can be successful.

Saccadic palsy after cardiac surgery: characteristics and pathogenesis.

OBJECTIVE: To characterize the syndrome of saccadic palsy that may follow cardiac surgery, and to interpret the findings using current concepts of the neurobiology of fast eye movements. METHODS: Using the magnetic search coil technique, we measured eye, eyelid, and head movements of 10 patients who developed selective palsy of saccades after cardiac surgery. RESULTS: Patients showed varying degrees of slowing and hypometria of saccades in the vertical plane or both horizontal and vertical planes, with complete loss of all saccades in one patient. Quick phases of nystagmus were also affected, but smooth pursuit, vergence, and the vestibuloocular reflex were usually spared. The smallest saccades were less slowed than larger saccades. Affected patients were visually disabled by loss of ability to voluntarily shift their direction of gaze. Blinks and head thrusts modestly improved the range and speed of voluntary movement. The syndrome usually followed aortic valve replacement. Common accompanying features included dysarthria, labile emotions, and unsteady gait. The saccadic palsy either improved during the early part of the course or remained static. INTERPRETATION: Selective loss of all forms of saccades, with sparing of other eye movements, indicates malfunction of the brainstem machinery that generates saccades. A current model of brainstem circuits could account for both hypometria and slowing. This syndrome and the visual disability it causes often go unrecognized unless saccades are systematically tested at the bedside.

Disorders of saccades.

Saccades are rapid eye movements that assist vision by pointing the fovea of the retina, which contains the highest density of photoreceptors, at features of interest in the visual environment. A great deal is now known about the properties and neurobiology of saccades in both health and disease states. They have consequently become a valuable diagnostic and research tool. In this review, we describe the common saccadic disorders and their causes. We also highlight recent insights into the pathophysiologic mechanisms underlying these disorders and discuss how these insights have helped increase our understanding of the saccadic system as a whole.

Ocular myasthenia revisited: insights from pseudo-internuclear ophthalmoplegia.

Ocular myasthenia can mimic central disorders of eye movements. We compared horizontal saccades in two patients with myasthenia gravis who presented as pseudo-internuclear ophthalmoplegia (pseudo-INO), two patients with true INO due to multiple sclerosis (MS), and five healthy subjects. In myasthenics, peak velocity of horizontal saccades was similar to, or greater than, controls; in MS patients, adducting saccades were slower than controls. Differences between the peak velocity of abducting and adducting eyes for each saccade were similar to controls for myasthenic pseudo-INO, but greater than controls for true INO. Using the technique of phase-plane analysis, in which eye velocity is plotted against eye position, we found that initial components of abducting and adducting saccades in the myasthenics were as conjugate as controls, even though later components of myasthenic saccades were highly and variably disjunctive. Conversely, phase planes of saccades in true INO showed disjunctive early components of abducting and adducting saccades. Two hypotheses have been offered to account for preservation of fast saccades despite reduced range of eye movements in ocular myasthenia. The first is intrasaccadic neuromuscular fatigue, which is variable over time. Our finding that initial components of saccades were consistently conjugate in the myasthenics gives support to a second hypothesis: selective sparing of pale global fibers, which are important for generating highspeed eye movements, and which are unique amongst extraocular fibers in possessing well developed synaptic folding.

Combining recessions (nystagmus and strabismus) with tenotomy improved visual function and decreased oscillopsia and diplopia in acquired downbeat nystagmus and in horizontal infantile nystagmus syndrome.

PURPOSE: To investigate the effects of combined tenotomy and recession procedures on both acquired downbeat nystagmus and horizontal infantile nystagmus. METHODS: Patient 1 had downbeat nystagmus with a chin-down (upgaze) position, oscillopsia, strabismus, and diplopia. Asymmetric superior rectus recessions and inferior rectus tenotomies reduced right hypertropia and rotated both eyes downward. Patient 2 had horizontal infantile nystagmus, a 20 degrees left-eye exotropia, and alternating (abducting-eye) fixation. Lateral rectus recessions and medial rectus tenotomies were performed. Horizontal and vertical eye movements were recorded pre- and postsurgically using high-speed digital video. The eXpanded Nystagmus Acuity Function (NAFX) and nystagmus amplitudes and frequencies were measured. RESULTS: Patient 1: The NAFX peak moved from 10 degrees up to primary position where NAFX values improved 17% and visual acuity increased 25%. Vertical NAFX increased across the -10 degrees to +5 degrees vertical range. Primary-position right hypertropia decreased approximately 50%; foveation time per cycle increased 102%; vertical amplitude, oscillopsia, and diplopia were reduced, and frequency was unchanged. Patient 2: Two lateral, narrow high-NAFX regions (due to alternating fixation) became one broad region with a 43% increase in primary position (acuity increased approximately 92.3%). Diplopia amplitude decreased; convergence and gaze holding were improved. Primary-position right exotropia was reduced; foveation time per cycle increased 257%; horizontal-component amplitude decreased 45.7%, and frequency remained unchanged. CONCLUSIONS: Combining tenotomy with nystagmus or strabismus recession procedures increased NAFX and visual acuities and reduced diplopia and oscillopsia in downbeat nystagmus and infantile nystagmus.

Effects of tenotomy on patients with infantile nystagmus syndrome: foveation improvement over a broadened visual field.

PURPOSE: To investigate the effects of four-muscle tenotomy on visual function and gaze angle in patients with infantile nystagmus syndrome (INS). METHODS: Eye movements of nine patients with infantile nystagmus were recorded using infrared reflection or high-speed digital video techniques. Experimental protocols were designed to record the patients' eye-movement waveforms, pre- and post-tenotomy, at different gaze angles. We used the eXpanded Nystagmus Acuity Function (NAFX) to measure tenotomy-induced changes in the nystagmus at primary position and various gaze angles. The longest foveation domains (LFD) were measured from fitted curves. Peak-to-peak nystagmus amplitudes and foveation-period durations were also measured. All measurements were made unmasked. RESULTS: All seven patients with narrow, high-NAFX, gaze-angle regions showed broadening of these regions of higher visual function. Three patients showed moderate NAFX improvement (13.9-32.6%) at primary position, five showed large improvement (39.9-162.4%), and one showed no NAFX change (due to his high pretenotomy NAFX). Primary position measured acuities improved in six patients. All patients had reductions in nystagmus amplitudes ranging from 14.6 to 37%. The duration of the foveation period increased in all nine patients (11.2-200%). The percentage improvements in both the NAFX and the LFD decreased with higher pretenotomy values. CONCLUSIONS: In addition to elevating primary position NAFX, tenotomy also broadens the high-NAFX regions. This broadening effect is more prominent in patients who had sharp pretenotomy NAFX peaks. Four-muscle tenotomy produces higher primary position NAFX increases in infantile nystagmus patients whose pretenotomy values are relatively low, with the improvement decreasing at higher pretenotomy values. The tenotomy procedure improves visual function beyond primary position acuity. This extends the utility of surgical therapy to several different classes of patients with INS for whom other procedures are contraindicated. The pretenotomy NAFX can now be used to predict both primary position acuity improvements and broadening of a patient's high-NAFX range of gaze angles.

Binocular diplopia. A practical approach.

BACKGROUND: Diplopia is a common complaint in both inpatient and outpatient neurologic practice. Its causes are many, and special historical and examination features are important to localization and accurate diagnosis. REVIEW SUMMARY: This review is divided into 2 sections: the first related to diagnosis and the second to treatment of binocular diplopia. In the diagnostic section, emphasis is placed on identification of historical and examination features that can help to differentiate diplopia caused by dysfunction of cranial nerves versus neuromuscular junction, or orbital extraocular muscle. Techniques available to the neurologist for examining ocular motility and ocular misalignment and focused laboratory testing to evaluate diplopia are discussed in detail. The final section covers the various treatments for binocular diplopia, with recommendations regarding the utility of each treatment for different types of diplopia. CONCLUSIONS: A logical step-by-step approach applied to each patient with diplopia will help prevent misdiagnosis and improve patient care.