Hemifield slide from traumatic optic chiasmopathy

The presenting visual symptoms of optic chiasmal disease

Recognising optic chiasmal disease early is important in order to avoid irreversible visual loss and the potential risk of mortality for patients. Yet, there is frequently a delay in the initial diagnosis. Whilst the signs of optic chiasmal disease, particularly the perimetric findings, are well documented in the recent literature, the symptoms have been less well reported. Whilst some patients with optic chiasmal disease will be asymptomatic, many will complain of visual symptoms including symptomatic field defects, problems with central vision, difficulty with near tasks, binocular visual disturbances, colour vision disturbances, photophobia, phosphenes, glare, and rarely, oscillopsia and visual hallucinations. Others may have headache or the severe and sudden visual symptoms associated with pituitary apoplexy. The visual symptoms may be vague or non-specific, even when there are significant bitemporal visual field defects. We aim in this review to describe the presenting visual symptoms of optic chiasmal disease, and to illustrate these with selected qualitative descriptions from the literature. Our hope is that this will aid clinicians in eliciting a careful history of the sometimes subtle symptoms that may be present.

Hemifield-slide diplopia successfully managed with botulinum toxin injection in a patient with traumatic chiasmal disruption

PURPOSE

This report describes the clinical course of the traumatic chiasmal syndrome and treatment of diplopia due to the hemifield-slide phenomenon.

CASE REPORT

A 20-year-old male with decreased vision in both eyes following blunt head trauma was referred to the neuro-ophthalmology clinic. Neuroimaging revealed disruption of the optic chiasm and skull base fracture. After partial vision recovery, the patient noticed complete bitemporal hemianopia. Three months later, he was exotropic and complained of diplopia and difficulty in near visual tasks. His symptoms were successfully controlled by injection of botulinum toxin A in both lateral rectus muscles.

CONCLUSIONS

There is some potential for improvement in vision in patients with traumatic chiasmal syndrome. Botulinum toxin could be used in patients with the hemifield-slide phenomenon to predict the sensory outcome of surgery and relieve the bothersome symptoms.

Visual and Positional Modulation of Pendular Seesaw Nystagmus: Implications for the Mechanism

BACKGROUND

The mechanisms of pendular seesaw nystagmus (SSN) remain unknown.

METHODS

We evaluated modulation of pendular SSN by removal of visual fixation, convergence, and positional changes in 2 patients, one with bitemporal hemianopia due to a traumatic damage of the optic chiasm and the other with platybasia compressing the medulla and lower cerebellum.

RESULTS

In both patients, the pendular SSN markedly decreased or disappeared with convergence, without visual fixation in darkness, during static head tilt toward each shoulder while sitting and while supine.

CONCLUSIONS

The similar patterns of nystagmus modulation observed in our patients with a different etiology indicate a common role of both visual and otolithic inputs in generating pendular SSN.

Visual problems associated with traumatic brain injury

Traumatic brain injury (TBI) and its associated concussion are major causes of disability and death. All ages can be affected but children, young adults and the elderly are particularly susceptible. A decline in mortality has resulted in many more individuals living with a disability caused by TBI including those affecting vision. This review describes: (1) the major clinical and pathological features of TBI; (2) the visual signs and symptoms associated with the disorder; and (3) discusses the assessment of quality of life and visual rehabilitation of the patient. Defects in primary vision such as visual acuity and visual fields, eye movement including vergence, saccadic and smooth pursuit movements, and in more complex aspects of vision involving visual perception, motion vision ('akinopsia'), and visuo-spatial function have all been reported in TBI. Eye movement dysfunction may be an early sign of TBI. Hence, TBI can result in a variety of visual problems, many patients exhibiting multiple visual defects in combination with a decline in overall health. Patients with chronic dysfunction following TBI may require occupational, vestibular, cognitive and other forms of physical therapy. Such patients may also benefit from visual rehabilitation, including reading-related oculomotor training and the prescribing of spectacles with a variety of tints and prism combinations.

Management of diplopia with visual-field defects

PURPOSE:

The management of diplopia can be challenging in patients with a concurrent visual-field (VF) defect. We conducted a retrospective chart review to analyze and compare treatment outcomes for different types of VF defects.

METHODS:

A retrospective chart review.

RESULTS:

Seven patients with diplopia and VF defects were identified during the study. Four had bitemporal hemianopia, one had homonymous hemianopia, and two had a constricted central VF. A favorable or satisfactory outcome was achieved in all but two patients with bitemporal hemianopia.

CONCLUSIONS:

The hemifield-slide diplopia may develop in patients with bitemporal hemianopia or heteronymous altitudinal visual defects. Sensory abnormalities usually persist, even after elimination of ocular misalignment.

The Craig Hospital Eye Evaluation Rating Scale (CHEERS)

BACKGROUND

Oculomotor deficits in smooth pursuit, saccades, vestibular-ocular reflex (VOR), vergence, and fixation are common problems seen after moderate to severe traumatic brain injury (TBI). No scale currently exists to rate all of these together. The Craig Hospital Eye Evaluation Rating Scale (CHEERS) was designed to systematically quantify frequency and severity of eye movement deficits in TBI.

OBJECTIVE

To assess the intra- and interrater reliability of a new rating scale for detecting the presence and degree of 5 oculomotor abnormalities after TBI.

DESIGN

A reliability study.

SETTING

This was an institution-based study at Craig Rehabilitation Hospital.

PARTICIPANTS

English-speaking patients between ages 18 and 65 years with a primary diagnosis of moderate to severe mechanical TBI and who were not blind in either eye were eligible.

METHODS

Between October 2013 and March 2014, a total of 11 TBI patients and 9 non-TBI controls were enrolled in the study. The median age was 30 years (range, 18-74 years) for subjects and 52 years (range, 28-63 years) for controls. All patients were male, and 8 of 9 controls were female. Eye movements (fixation, smooth pursuit, saccade, convergence, and vestibular-ocular reflex) were recorded for each on digital video. They were rated on 2 separate occasions by each of the 2 raters.

MAIN OUTCOME MEASUREMENTS

Inter- and intrarater reliability tests.

RESULTS

Median elapsed time between the first and second ratings was 7 days (range, 5-44 days). Intrarater agreement was very strong (Spearman ρ ≥ 0.900) for pursuit, saccades, and VOR for both raters, and strong (Spearman ρ ≥ 0.710) for vergence and fixation. The interrater agreement for detecting presence of any oculomotor abnormality was substantial (unweighted κ = 0.63). The interrater concordance on the full range of scale scoring was strongest on the VOR test (weighted κ = 0.98), was substantial for vergence, pursuit, saccades, and total score (weighted κ > 0.60), and was moderate for fixation. For TBI patients, every eye movement rated was found to be more abnormal than compared to those in the controls.

CONCLUSIONS

CHEERS is a reliable scale for assessing and quantifying oculomotor deficits commonly observed in moderate to severe TBI. Further studies to validate the scale's utility in outcome prediction, and its applicability to broader brain injury populations, are warranted.

LEVEL OF EVIDENCE

IV.

Non-compressive disorders of the chiasm

Chiasmal dysfunction produces a characteristic clinical picture, regardless of the mechanism. In most cases a compressive lesion is the cause. In occasional cases, however, no such extrinsic mass is found and other possible etiologies must be explored. In some of these cases, the pathologic process is identifiable with appropriate neuroimaging. For example, inflammation, infiltrative tumors, and radiation necrosis produce intrinsic chiasmal enhancement. Chiasmal ischemia may require specialized magnetic resonance (MR) sequences for diagnosis. Chiasmal hemorrhage, trauma and chiasmal herniation typically produce distinctive changes on noncontrasted imaging. In cases of metabolic insult, either toxic or hereditary, radiographic changes are typically absent. In each of these, the correct diagnosis can usually be made with a combination of clinical and radiographic features.