Nystagmus is of two types, the jerking type and pendular type. In general, the jerking type is considered as a typical nystagmus. Nystagmus has two phases, namely the slow phase and the rapid phase and is caused by damage to one or more regions of the vestibular system, including the semicircular canals, otolith organs, and vestibular nerve as a transmission pathway.Benign paroxysmal positional vertigo (BPPV) is commonly observed in patients with vertigo and occurs in 30-40% of patients with vertigo. The frequency of BPPV is higher in middle-aged and older women than in younger women. Symptoms of BPPV are triggered by specific changes in the position of the head, such as tipping the head up or down, and by lying down, turning over, or sitting up, and torsional-vertical nystagmus is observed simultaneously. BPPV is benign i.e., it is not life threatening nor is it generally progressive.

View full abstract

Horizontal canal type of benign paroxysmal positioning vertigo (H-BPPV) is the most common cause of direction-changing positional nystagmus. H-BPPV is caused by either canalolithiasis or cupulolithiasis and affects the horizontal semicircular canal (HSCC). When a patient with HSCC canalolithiasis makes a lateral head turn toward the affected ear, the free-floating debris create an ampullopetal endolymph flow. As a result, a geotropic nystagmus (fast phase toward the ground) manifests. When the patient turns away from the affected side, the free-floating debris create an ampullofugal flow. On the other hand, when the patient with HSCC cupulolithiasis makes a lateral head turn toward the affected ear, the cupula undergoes an ampullofugal deflection causing an apogeotropic nystagmus (fast phase against the ground), and a head turn to the opposite side creates an ampullopetal deflection. There have been reports of a transition from an apogeotropic positional nystagmus to a geotropic positional nystagmus in same patient with H-BPPV, thereby suggesting the transformation from cupulolithiasis into canalolithiasis within the HSCC. Some cases show geotropic positional nystagmus, which is not transient but persistent. Because a heavy cupula is believed to form the pathophysiological basis of apogeotropic nystagmus, it is conversely suggested that persistent geotropic positional nystagmus is induced by a light cupula.

View full abstract

Ocular flutter is characterized by intermittent bursts of horizontal saccades lacking an intersaccadic interval. Similar saccadic bursts are called opsoclonus when they are directed not only horizontally, but also vertically and torsionally. Although the precise mechanisms are unknown, ocular flutter and opsoclonus are often observed in cerebellar and/or brainstem lesions. The causes of ocular flutter and opsoclonus are varied and include para-infectious brainstem encephalitis, metabolic toxic states, demyelinating diseases, and paraneoplastic syndrome (neuroblastoma in children, and small cell lung carcinoma in adults). Paraneoplastic, para-infectious, and idiopathic ocular flutter/opsoclonus are sometimes treated with steroids or intravenous immunoglobulin.

View full abstract

It is well known that the primary feature of nystagmus is a drift of the eyes from the desired position of the eyes; saccadic intrusions, however, are characterized by inappropriate saccadic movements that interfere with steady fixation. Several types of saccadic intrusions have their own salient features including the presence or absence or duration of their saccadic intervals. In this article, we aim to update readers on the latest advances in understanding square-wave jerks (SWJs) and macrosaccadic oscillations (MSOs), in which the abnormal eye movements have saccadic intervals, and present video clips and electrooculograms of the typical eye movements for a comparison. SWJs are small, conjugated saccades, ranging from 0.5 to 5 degrees (usually less than 2 degrees) in size, which take the eyes away from the fixation position, subsequently returning to the original position after a period of about 200 ms. SWJs are commonly found in healthy subjects, especially the elderly; they occur frequently in cerebral disease, spinocerebellar degeneration, and progressive supranuclear palsy. SWJs may likely result from abnormally enlarged microsaccades that play a pivotal role in optimizing the perception of an object by shifting the image on the retina in small portions of approximately 0.5 degrees. On the other hand, MSOs are a rare form of large-sized saccadic oscillations around the fixation point that wax and wane, reportedly with a“normal”saccadic interval of 200 ms, and were documented in cerebellar disorders and myasthenia gravis with edrophonium administration. MSOs, however, are considered to be an enhanced variation of saccadic hypermetria with the saccadic gain over 2.0, and therefore, the saccadic interval of MSOs should be the same as that of short-latency corrective saccades after saccadic hypermetria, which is around 125 ms in reported cases.

View full abstract

Ping-pong, or short-cycle periodic alternating, gaze, consists of horizontal conjugate ocular deviations alternating every few seconds. It is usually seen in unconscious patients with bilateral impairment of the cerebral hemispheres, and implies that brain stem function is relatively intact. This alternating gaze has been described as smooth in appearance. Saccadic ping-pong gaze, first described by us, is a clinical variant of ping-pong gaze occurring in patients in a higher state of consciousness, and is possibly related to less extensive or severe brain damage.

View full abstract

We report a case of Leber's hereditary optic neuropathy (LHON) wherein the temporal peripapillary retinal nerve fiber layer (RNFL) thickness in the right eye increased at the onset of the disease and decreased more quickly than that in the other quadrants. A 38-year-old male developed left followed by right optic neuropathy within a span of 6 months. Changes in the temporal peripapillary RNFL thickness were determined using optical coherence tomography (OCT). In the early stages of the disease, the temporal RNFL thickness increased in both eyes. In the right eye in particular, we observed that the temporal RNFL thickness increased just before the onset of the disease and rapidly decreased thereafter, whereas the RNFL thickness in the other quadrants persistently increased after disease onset. The papillomacular nerve fibers are preferentially damaged in LHON. The findings from this case suggest that the axonal flow of these fibers is the first to undergo serious damage, consistent with the clinical characteristics of LHON.

View full abstract

In the present report, we describe a patient with sarcoidosis and recurrent blepharoptosis that responded well to systemic corticosteroid therapy. A 36-year-old woman with pulmonary sarcoidosis who had been treated with oral prednisolone (5 mg/day) developed blepharoptosis at the left eye that exhibited irregular changes (worsening as well as inprovement) within 24 hours. The serum anti-acetylcholine receptor antibody levels were not elevated, and both the Tensilon test and ice-pack test yielded negative results. Three months later, the oral prednisolone dose increased to 30 mg/day due to deterioration of the pulmonary lesion. After systemic corticosteroid therapy, the blepharoptosis disappeared. Based on the findings of the present report, we believe that sarcoidosis should be considered as a cause of blepharoptosis.

View full abstract

Efficacy of monovision correction in the treatment of acquired binocular diplopia is reported in this study. Three adult patients who suffered diplopia due to ophthalmoplegia were prescribed glasses for monovision correction. Strabismus surgery or prismatic correction could not be applied in these patients. Each patient wore glasses with distance correction in the dominant eye and near correction in the nondominant eye. Each of them reported reduction of diplopia to a considerable extent. One patient always wore glasses when he left the home. However, the remaining two patients wore glasses occasionally. Based on these observations, I consider that monovision glasses may be useful for patients who are dissatisfied with other treatments for diplopia.

View full abstract

The ocular tilt reaction (OTR) is a triad consisting of a head tilt, conjugate ocular torsion in the direction of head tilt, and skew deviation. The OTR must be carefully distinguished from trochlear nerve palsy, as both conditions can mimic each other. Here, I present a case of OTR and discuss how to differentiate this condition from trochlear nerve palsy.

View full abstract

Purpose: To study the relationship of pupillary parameters in the hand-held digital pupillometer and the iriscorder pupillometer.
Methods: The study examined 15 eyes of 15 healthy subjects with a mean age of 29 years (range: 22 to 39 years). The pupillary light response were measured by using a white stimulus from a hand-held digital NPi-100 pupillometer and red (635 nm) and blue (470 nm) stimuli at two intensities (10 cd/m² and 100 cd/m²) from an iriscorder pupillometer after 3 minutes of dark adaptation. Pupillary parameters were analyzed using Intraclass Correlation Coefficient (ICC).
Results: There was a significant correlation in pupil diameters between the polychromatic white and chromatic red (r=0.51-0.54; P=0.02 to 0.01) and blue stimuli (r=0.53-0.69; P=0.01 to 0.002).The contraction rate and the maximum constriction velocity showed greater responses to the blue stimulus than to the white and red stimuli (r=0.14-0.55; P=0.30 to 0.01), as well as a significant correlation between the white and blue stimuli (r=0.25-0.77; P=0.17 to 0.0001). The latency time have a correlation between the white and red (r=0.28-0.44; P=0.04 to 0.14), and blue stimuli (r=0.25-0.27; P=0.15 to 0.17).
Conclusions: The polychromatic pupillometer demonstrates correlation with a chromatic pupillometer in pupil diameter and in the pattern of contraction in normal subjects. Our data can provide useful protocols for further clinical studies for screening and detecting diseases affecting pupil size and pupillary responses.

View full abstract