Upper and lower eyelid saccades describe a harmonic oscillator function

PURPOSE: To determine whether experimentally measured upper and lower eyelid saccades can be fitted to a mathematical function. METHODS: A charge-coupled device video camera connected to a personal computer was used to record upper and lower eyelid saccades accompanying 20 degrees and 40 degrees of vertical eye rotation in 19 normal adult subjects. Movement analysis was performed with software that calculated the center of a blue spot in each frame. The damped harmonic oscillator model was used to fit all saccadic functions obtained. RESULTS: All downward and upward saccades of both upper and lower eyelids were fitted with the underdamped solution of the model with correlation coefficients ranging from 0.980 to 0.999 (mean = 0.995). It was possible to measure maximum velocity at any time, amplitude, and duration of the saccade movements. For the upper eyelid, downward saccades were faster than upward saccades, a difference that was not observed for the lower eyelid. For both the upper and lower eyelids, the velocity of upward and downward movements reached a peak at approximately 0.05/0.06 second and then decreased. For both the upper and lower eyelid saccades, there was good linear correlation between amplitude and velocity. Overshoots were detected in the downward saccades of both lids. CONCLUSIONS: Normal upper and lower saccades are described by functions that are extremely well fitted by the underdamped solution of the harmonic oscillator model. Overshooting is a typical feature of normal downward saccades and can be explained by the elastic properties of the tissues.     

Effects of unilateral ocular motor nerve palsies on smooth pursuit eye movements in adult patients

AIM: The aim of this study was to investigate the influence of single ocular muscle weakness on smooth pursuit eye movements. METHODS: Infrared video recordings of horizontal and vertical eye movements were obtained from 14 adult patients with either unilateral abducens nerve palsy or trochlear nerve palsy. During the recordings, subsequent series of horizontal, vertical and oblique ramp stimuli of 10 degrees/s constant target velocity and +/-10 degrees amplitude were presented under monocular viewing conditions. RESULTS: In both forms of ocular nerve palsies, similar changes of pursuit eye movements were observed in the pulling plane of the paretic muscles. The movements of the covered paretic eye showed the lowest amplitude and gain values as well as the lowest numbers of catch-up saccades. The highest amplitude and gain values were calculated from the movements of the covered sound eye. The highest numbers of saccades, however, were produced by the fixating paretic eye. CONCLUSIONS: We conclude that the fixating paretic eye compensates for the paresis by raising the pursuit gain and the number of catch-up saccades. In the covered paretic eye, however, monocular adaptation is connected with a symmetric low pursuit gain and a reduced number of saccades in the pulling plane of the paretic muscle.     

Upper eyelid motility in blepharoptosis and in the aging eyelid

PURPOSE. To study the metrics of lid saccades in blepharoptosis and to distinguish any differences in the dynamics of eyelid movements that are related to the cause of blepharoptosis and to aging. METHODS. The lid and vertical eye saccades of 7 patients with congenital blepharoptosis and those of 18 patients with aponeurogenic blepharoptosis, either involutional or rigid-contact-lens-induced, were recorded with electromagnetic search coils. For each saccade, two parameters were assessed: amplitude and peak velocity. Two age-matched control groups were assessed in the same manner. Repeated measures analysis of variance was used to investigate any observed differences between the included groups. RESULTS. Congenital and rigid-contact-lens-induced blepharoptosis were readily distinguishable from one another, as well as from the age-matched control group, in both lid saccadic amplitude and peak velocity. For example, 40 degrees downward lid saccades in the congenital blepharoptosis group averaged 22.9 degrees +/- 4.0 degrees (SD), whereas 30.0 degrees +/- 4.7 degrees lid saccades were made by the age-matched control group. The subjects in the two groups with aponeurogenic blepharoptosis also made lid saccades that were distinctive for their group (P: < 0.02), in both amplitude and peak velocity. For 40 degrees downward saccades in involutional and rigid-contact-lens-induced blepharoptosis, lid saccadic amplitude averaged 32.7 degrees +/- 4.3 degrees and 40.3 degrees +/- 3.5 degrees, respectively. Lid saccadic peak velocity declined significantly with age. Lid saccadic peak velocity for 40 degrees upward saccades in the younger control group averaged 401.7 +/- 11.4 deg/sec, whereas the older control group achieved an average peak velocity of 360.7 +/- 60.4 deg/sec. The lid saccadic dynamics in the involutional blepharoptosis group proved to be similar (P: > 0.05) in saccadic amplitude and peak velocity to those of age-matched controls. CONCLUSIONS. In different forms of blepharoptosis, distinctive metrics of lid saccades occur. The current data suggest that involutional blepharoptosis is not a consequence of normal age-related changes in eyelid function.     

Eye tracking disturbances in schizophrenia

PURPOSE: To study the frequency of different types of eye tracking disturbances in schizophrenia. MATERIALS AND METHODS: Smooth pursuit eye movements were studied by electro-oculography (EOG) in 22 schizophrenic patients (ICD-10 criteria) and 15 age and sex-matched controls. The studied parameters included average pursuit gain, number of saccades, the frequency of different types of saccades (catch-up, back-up, anticipatory saccades), and disturbances during fixation. The results were analysed statistically. RESULTS: The average pursuit gain was significantly affected in patients for target velocity of 30 degrees/sec (p = 0.007). The catch-up and back-up saccades were more common in cases than controls but the difference was not significant (p = 0.39 and 0.36 respectively). The anticipatory saccades were significantly more frequent in cases than controls (p < 0.0001) for both 15 degrees/sec and 30 degrees/sec target velocities. This was also correlated with the duration of illness. CONCLUSION: Anticipatory saccades are significantly more frequent during eye tracking in schizophrenia and appear to be an objective marker for the disease.     

Effect of darkness on upper eyelid position

PURPOSE: To determine the magnitude of upper eyelid retraction induced by sudden darkness in normal subjects and in patients with Graves upper eyelid retraction before and after treatment with guanethidine drops. METHODS: The study comprised 211 control subjects (n=211 eyes) and 45 patients (n=78 eyes) with Graves upper eyelid retraction. The control subjects were divided in four age groups: 0 to 1 year, 2 to 9 years, 0 to 18 years, and 19 to 61 years. Twenty-one patients with Graves upper eyelid retraction (n=39 eyes) used guanethidine drops for 15 days. Palpebral fissure images of subjects were acquired in photopic conditions and in darkness. For both images, the distance between the mid-pupil and upper eyelid margin was measured. RESULTS: Darkness induced upper eyelid retraction in all subjects. The increment in the mid-pupil eyelid distance was greater in children. There was no significant difference between the magnitude of eyelid elevation of Graves patients and normal adults. Guanethidine drops did not abolish the eyelid reflex in Graves patients. CONCLUSIONS: Darkness provokes upper eyelid retraction in control subjects and in patients with Graves upper eyelid retraction. This effect decreases with age and does not result from sympathetic stimulation of the Muller muscle.     

提上睑肌MRI改变与Graves眶病上睑迟落的相关性研究

目的探讨提上睑肌MRI改变与Graves眶病上睑迟落的相关性。设计前瞻性病例系列。研究对象20例（20眼）正常志愿者,8例（10眼）Graves眶病无上睑迟落患者,7例（10眼）上睑迟落患者。方法受检者应用眼表面线圈,于前视眼位、上视眼位及下视眼位行斜冠状面、斜矢状面T1WI扫描。主要指标各眼位提上睑肌横截面积、厚度,腱膜上方脂肪厚度,提上睑肌收缩率、舒张率。结果正常者提上睑肌各眼位横截面积、厚度、腱膜上方脂肪厚度、收缩率、舒张率在侧别、性别及年龄间差异无统计学意义（P均〉0．05）。提上睑肌在上视眼位横截面积（17．93±4．48）mm2,厚度（2．21±0．22）mm较前视眼位增加,下视眼位横截面积（5．48±1．32）mm2、厚度（1．11±1．15）mm较前视眼位减小（p均〈0．05）。Graves眶病患者各眼位提上睑肌横截面积、厚度及腱膜上方脂肪厚度较正常者均增加,提上睑肌收缩率、舒张率均减小（P均〈0．05）。迟落征患者较无迟落征患者,下视眼位提上睑肌厚度（2．74±0．71）mm及腱膜上方脂肪厚度（1．94±0．54）mm明显增加,面积舒张率0．12±0．14和厚度舒张率0．11±0．08明显减小（P均〈0．05）。结论Graves眶病患者下视眼位提上睑肌厚度、舒张率及腱膜上方脂肪厚度的变化与上睑迟落关系密切。     

Effects of Unilateral Ocular Motor Nerve Palsies on Smooth Pursuit Eye Movements in Adult Patients

Aim: The aim of this study was to investigate the influence of single ocular muscle weakness on smooth pursuit eye movements. Methods: Infrared video recordings of horizontal and vertical eye movements were obtained from 14 adult patients with either unilateral abducens nerve palsy or trochlear nerve palsy. During the recordings, subsequent series of horizontal, vertical and oblique ramp stimuli of 10°/s constant target velocity and ±10° amplitude were presented under monocular viewing conditions. Results: In both forms of ocular nerve palsies, similar changes of pursuit eye movements were observed in the pulling plane of the paretic muscles. The movements of the covered paretic eye showed the lowest amplitude and gain values as well as the lowest numbers of catch-up saccades. The highest amplitude and gain values were calculated from the movements of the covered sound eye. The highest numbers of saccades, however, were produced by the fixating paretic eye. Conclusions: We conclude that the fixating paretic eye compensates for the paresis by raising the pursuit gain and the number of catch-up saccades. In the covered paretic eye, however, monocular adaptation is connected with a symmetric low pursuit gain and a reduced number of saccades in the pulling plane of the paretic muscle.     

Ultrasound biomicroscopy of the levator aponeurosis in congenital and aponeurotic blepharoptosis

PURPOSE: To evaluate and measure the thickness of the levator aponeurosis by ultrasound biomicroscopy in congenital dysmyogenic and aponeurotic blepharoptosis. METHODS: Forty-four upper eyelids of 22 patients who had unilateral blepharoptosis were evaluated by ultrasound biomicroscopy. The patients ranged in age from 13 to 69 years (mean, 35.4 +/- 20.2 years). Fourteen patients were male and 8 patients were female. Seven patients had congenital dysmyogenic blepharoptosis and 15 patients had aponeurotic blepharoptosis. Imaging was performed with a 50-MHz transducer. The thickness of the levator aponeurosis was measured centrally at the upper border of the tarsus. RESULTS: The levator aponeurosis was imaged in all eyelids except for one eyelid with aponeurotic blepharoptosis. The mean thickness of the levator aponeurosis was 0.39 +/- 0.10 mm in the ptotic eyelid and 0.42 +/- 0.09 mm in the control eyelid of the patients with congenital dysmyogenic blepharoptosis (p = 0.043). The mean thickness of the levator aponeurosis was 0.26 +/- 0.05 mm in the ptotic eyelid and 0.36 +/- 0.04 mm in the control eyelid of the patients with aponeurotic blepharoptosis (p = 0.001). The thickness of the levator aponeurosis was correlated with the palpebral fissure height (p = 0.013, r = 0.644) in aponeurotic blepharoptosis. The thickness of the levator aponeurosis was correlated with the levator function (p = 0.033, r = 0.795) in congenital dysmyogenic blepharoptosis. CONCLUSIONS: The thickness of the levator aponeurosis can be measured with ultrasound biomicroscopy. The most common pathology in aponeurotic blepharoptosis is thinned-out aponeurosis. The levator aponeurosis of the ptotic eyelid is thinner than the normal eyelid in congenital ptosis.     

Quantitative comparison between upper eyelid retraction induced voluntarily and by Graves orbitopathy

PURPOSE: To compare 2-dimensional palpebral fissure measurements of normal subjects with voluntary upper eyelid retraction and patients with Graves upper eyelid retraction. METHODS: Three groups of monocular palpebral fissure images were measured. Group 1 consisted of 32 images of healthy subjects with the upper eyelid in a normal position of rest. Group 2 included the same subjects with voluntary upper eyelid retraction. Group 3 included 45 images of patients with Graves upper eyelid retraction. Fissure images were acquired with a digital camera and transferred to a Macintosh computer. For all images, three variables were quantified with NIH Image software: the midpupil-to-upper eyelid margin distance and the nasal and temporal upper areas of the palpebral fissure. RESULTS: Voluntary upper eyelid retraction significantly increases the absolute difference between the temporal and nasal areas of normal subjects. The disproportion between the lateral and medial areas of the palpebral fissure was greater for the patients with Graves than for the control group with voluntary eyelid retraction, even though there was no difference between the midpupil-to-upper eyelid margin distance of these two groups. Overall, there was a positive correlation between the midpupil-to-upper eyelid margin distance and absolute difference between the temporal and nasal areas (r = 0.75, P < 0.0001). CONCLUSIONS: In normal subjects, voluntary upper eyelid retraction increases the disproportion between the lateral and medial aspects of the fissure. However, even for the same amount of eyelid elevation, the mean disproportion of the control group with voluntary eyelid retraction is smaller than the disproportion displayed by patients with Graves. These findings suggest that an enhanced lateral retraction is a normal finding associated with levator muscle contraction.     

Upper eyelid movements measured with a search coil during blinks and vertical saccades.

Upper eyelid movements were recorded in nine human subjects by mounting a miniature coil of wire directly on the eyelid and subjecting the search coil to a vertically directed alternating magnetic field. The metrics of blinks and lid movements accompanying saccades were described by "main sequence" relationships, linking maximum velocity to amplitude and duration to amplitude. In general, lid movements were faster than those reported previously in the literature, but there was considerable intersubject variability. On average, the main sequence relationships for blinks were independent of either starting lid position or whether the blinks were generated spontaneously, reflexively, or voluntarily. For the down phase of the average blink, both the maximum velocity and duration increased almost linearly with amplitude. The maximum velocity of the down phase was faster than that of the up phase. For lid movements accompanying vertical saccades, the maximum velocities in the up and down directions were similar and increased nonlinearly with amplitude, saturating at about 120 mm/sec (approximately 450 degrees/sec). Duration increased approximately linearly with amplitude. The down phases of blinks were much faster than those of saccade-related lid movements. By comparison, the maximum velocities of the up phase of blinks and of saccade-related lid movements were almost equal. The large intersubject variability suggests caution when using normative data to interpret abnormal lid motion for clinical purposes.     

Preaponeurotic Fat Advancement for Prevention of Unexpected Higher Eyelid Crease in Upper Eyelid-Lengthening Surgery

Purpose: To present a modified technique based on preaponeurotic fat advancement for preventing higher eyelid crease in upper eyelid-lengthening surgery.

Methods: Outcomes of Japanese patients with Graves’ orbitopathy-related upper eyelid retraction who underwent transcutaneous upper eyelid-lengthening surgery were reviewed. The minimum follow-up period was 6 months. A total of 17 upper eyelids in 11 patients (average age, 38.4 years) were included. After confirming appropriate upper eyelid lowering with good contour, preaponeurotic fat was fully exposed and fixed on the upper tarsal plate 1?mm superior to the planned eyelid crease with 5 sutures. Skin-tarsus-skin sutures were placed to create an eyelid crease and close the skin. Simple suture tarsorrhaphy was performed with 2 sutures.

Results: No upper eyelids demonstrated higher eyelid crease postsurgically. Upper eyelid fullness caused by the advanced preaponeurotic fat was not conspicuous.

Conclusions: Our technique is a countermeasure against higher eyelid crease in upper eyelid-lengthening surgery.     

Graded full-thickness anterior blepharotomy for correction of upper eyelid retraction not associated with thyroid eye disease

PURPOSE: To evaluate the efficacy of graded full-thickness anterior blepharotomy for upper eyelid retraction of various causes not associated with Graves eye disease. METHODS: Twenty-one eyelids of 18 patients with upper eyelid retraction not caused by Graves eye disease were treated with graded full-thickness anterior blepharotomy. Preoperative and postoperative symptoms, midpupil to upper eyelid distance, lagophthalmos, and superficial punctuate keratopathy were evaluated. RESULTS: Upper eyelid retraction was due to facial nerve palsy in 4 patients (22%), overcorrected ptosis in 5 patients (28%), and cicatrix after trauma in 6 patients (33%). One patient each (6% each) had retraction from graft-versus-host disease, after blepharoplasty, and after orbicularis oculi myectomy for blepharospasm. At a mean of 10 months follow-up, presenting symptoms resolved or improved in 17 patients (94%) and remained unchanged in 1 patient (6%). Midpupil to upper eyelid distance, lagophthalmos, and superficial punctuate keratopathy all improved significantly (all p < 0.001). No surgical complications occurred. CONCLUSIONS: Graded full-thickness anterior blepharotomy is a safe, effective, and rapid technique for patients with symptomatic upper eyelid retraction due to etiologies other than Graves eye disease. This technique improves symptoms and signs of ocular exposure while addressing relative upper eyelid height symmetry and contour.     

Videonystagmography to assess blinking

BACKGROUND: In order to measure blinking, we developed a dynamic device consisting of a CCD camera connected to a videonystagmography machine. We developed an artificial pupil that allowed the camera to track movements of the upper eyelid. METHODS: Blinking parameters were measured in eight healthy volunteers, studying spontaneous blinking (SB) and voluntary blinking (VB) responses. Closing time, opening time, closing speed, vertical amplitude, horizontal amplitude and frequency of spontaneous blinking were recorded. RESULTS: In SB, opening time (0.21 +/- 0.04 s) was significantly longer than closing time (0.10 +/- 0.02 s) (p < 0.0001). Mean closing speed was 87 +/- 26 m/s in SB and 168 +/- 59 m/s in VB. Mean vertical amplitude was 9.1 +/- 2.2 mm. Mean vertical amplitude was lower in SB (9.1 +/- 2.2 mm) than in VB (12.3 +/- 1.9 mm) (p < 0.001). Mean horizontal amplitude was also lower in SB (2.7 +/- 0.9 mm) than in VB (3.8 +/- 0.9 mm) (p < 0.05). Frequency of SB was 18.4 +/- 3.4 per minute. CONCLUSIONS: Computer-assisted video acquisition provides real-time measurement of eyeblink dynamics. On healthy volunteers, this method enables accurate measurement of opening and closing responses as well as associated horizontal movement, and enables differentiating spontaneous and voluntary blinking.     

Acquired ocular motor apraxia: A clinico-pathological study

Acquired ocular motor apraxia is characterized by the inability to initiate intentional saccades. Saccades evoked by vestibular stimulation are present. Bilateral lesions involving the frontal and parietal cortex are hypothesized. The number of clinico-pathological studies is small; lesions are usually extensive.

Case report: A 73-year-old woman was reanimated after a cardiac arrest. She rapidly recovered. Consciousness was normal. There was no limb paralysis. Facial and eyelid movements were normal, spontaneous and on command. Pupillary light reflex was present. The eyes were in the midline position and immobile. Intentional saccades, to command and visually guided, were absent in the horizontal and vertical planes. Sporadically, saccade on command elicited a head movement associated with a slow vestibular eye movement in the opposite direction. Smooth pursuit was absent in all directions. Optokinetic stimulation provoked no eye movements. Oculocephalic movements were present. Cold water irrigation of one ear provoked a tonic deviation of both eyes to the irrigated side with irregular small corrective saccades to the other side. The patient died 30 days after the appearance of the eye movement disorder.

Autopsy findings: The brainstem was normal, especially the collicular area. Circumscribed areas of pseudo-laminar necrosis were present in the superior bank of the left inferior frontal sulcus (middle frontal gyrus), immediately anterior to the precentral gyrus and in the upper and lower banks of the left intra-parietal sulcus, involving the angular gyrus. The left frontal lesion was 7 mm long in the coronal plane and was seen on only one section, with slices taken every 5 mm. The left parietal lesion had a length of 15 mm in the coronal plane and was seen on two consecutive sections. On the right side cortical micro-infarctions were seen in the same areas. The lesions are compatible with 30-day-old ischemia and are interpreted as border zone infarcts after systemic hypotension.

Our case is very similar to the case reported by Pierrot-Deseilligny et al.¹ in which the lesions were visualized by MRI. Small lesions as observed in our case are rare and are important for location of the human cortical areas involved in the control of saccades. Our findings confirm that small bilateral lesions in the posterior part of the middle frontal gyrus (frontal eye field) and in the posterior parietal lobule can completely abolish intentional saccades and smooth pursuit eye movements.     

Eye movements during visual search in patients with glaucoma

ABSTRACT: BACKGROUND: Glaucoma has been shown to lead to disability in many daily tasks including visual search. This study aims to determine whether the saccadic eye movements of people with glaucoma differ from those of people with normal vision, and to investigate the association between eye movements and impaired visual search. METHODS: Forty patients (mean age: 67 [SD: 9] years) with a range of glaucomatous visual field (VF) defects in both eyes (mean best eye mean deviation [MD]: --5.9 (SD: 5.4) dB) and 40 age-related people with normal vision (mean age: 66 [SD: 10] years) were timed as they searched for a series of target objects in computer displayed photographs of real world scenes. Eye movements were simultaneously recorded using an eye tracker. Average number of saccades per second, average saccade amplitude and average search duration across trials were recorded. These response variables were compared with measurements of VF and contrast sensitivity. RESULTS: The average rate of saccades made by the patient group was significantly smaller than the number made by controls during the visual search task (P = 0.02; mean reduction of 5.6 % (95 % CI: 0.1 to 10.4 %). There was no difference in average saccade amplitude between the patients and the controls (P = 0.09). Average number of saccades was weakly correlated with aspects of visual function, with patients with worse contrast sensitivity (PR logCS; Spearman's rho: 0.42; P = 0.006) and more severe VF defects (best eye MD; Spearman's rho: 0.34; P = 0.037) tending to make less eye movements during the task. Average detection time in the search task was associated with the average rate of saccades in the patient group (Spearman's rho = [MINUS SIGN]0.65; P < 0.001) but this was not apparent in the controls. CONCLUSIONS: The average rate of saccades made during visual search by this group of patients was fewer than those made by people with normal vision of a similar average age. There was wide variability in saccade rate in the patients but there was an association between an increase in this measure and better performance in the search task. Assessment of eye movements in individuals with glaucoma might provide insight into the functional deficits of the disease.     

Pre-Whitnall levator recession with hang-back sutures in Graves orbitopathy

PURPOSE: To describe a technique for lengthening the levator palpebrae muscle at the level of the transverse orbital ligament (Whitnall ligament) by using hang-back sutures in cases of upper eyelid retraction in Graves orbitopathy, and to report its results. METHODS: A cohort of consecutive patients undergoing this procedure by a single surgeon was analyzed. The surgical technique involved division of the levator muscle high up, at the level of the transverse orbital ligament, with lengthening of the muscle by a graded amount with the use of nonabsorbable hang-back sutures. The length of the sutures was twice the amount of desired lowering of the eyelid. RESULTS: Surgery was performed on 38 eyelids of 21 patients. The mean preoperative eyelid retraction was 4.7 mm (range, 3 mm to 8 mm). Thirty-two eyelids (84%) were within 1 mm of the desired postoperative position. One patient required reoperation for significant undercorrection (2 eyelids), another 4 had ptosis repairs for overcorrection (5 eyelids, one of which was only 1-mm overcorrected). One eyelid required medial contour repair, but none needed lateral contour correction. CONCLUSIONS: This procedure gives a relatively predictable result in patients with moderate to severe upper eyelid retraction and avoids the postoperative complication of contour deformities, especially lateral flare.     

Slow target-directed eye movements in ataxia-telangiectasia

PURPOSE: To analyze the slow eye movements that shift the direction of gaze in patients with ataxia-telangiectasia (A-T). METHODS: Eye and head movements were recorded with search coils in three patients with A-T during attempted gaze shifts, both with the head immobilized and free to move. RESULTS: Gaze shifts frequently included both saccadic and slow components. The slow movements were recorded after 42% of saccades and had an average peak velocity of 6.1 deg/sec and a mean amplitude of 2.0. They occurred with the head stationary and moving, could be directed centripetally or centrifugally, had velocity waveforms that were relatively linear or exponential, and always moved the eyes toward the visual target. CONCLUSIONS: The slow movements appear to differ from pursuit and vestibular eye movements and are not fully explained by the various types of abnormal eye movements that can follow saccades, such as gaze-evoked nystagmus or postsaccadic drift. Their origin is uncertain, but they could represent very slow saccades, due to aberrant inhibition of burst cell activity during the saccade.     

A directional impairment of eye movement control in strabismus amblyopia.

Saccadic and pursuit tracking movements were elicited to determine the ability of the amblyopic eye to sense and respond to position and motion of the retinal image. Amblyopic eyes were found to initiate saccades as rapidly as normal eyes (200 to 300 msec.), however, the amblyopic eye's saccades were reduced in amplitude, highly variable, and required refinement by subsequent saccades, particularly in response to nasalward displacements of the retinal image. Pursuit responses of amblyopic eyes to both constant and sinusoidal velocity targets contained brief periods of abnormally slow following movements interrupted by position-corrective saccades. As with the saccadic response, the amblyopic eye's pursuit movements were more accurate for temporal than for nasal retinal image motion. Abnormal saccadic and pursuit eye movements in amblyopia result from reduced monocular position and velocity sensitivity probably associated with binocular suppression scotomas normally found in amblyopia.     

Pursuit eye movements in chronic schizophrenics: relationship between increased saccades and negative symptoms

Smooth pursuit eye movements of chronic schizophrenics ( n = 16) and controls ( n = 10) were recorded while subjects tracked a sinusoidally-moving target. Negative symptoms in schizophrenics were rated using the Schedule for the Assessment of Negative Symptoms. An increased frequency of smooth pursuit eye movement abnormalities was found in the schizophrenic group, including greater variability of gain and more frequent and larger saccades. Frequency of saccades was positively correlated with the Negative Symptoms scales for attentional impairment and alogia. The results confirm findings of eye movement dysfunction in schizophrenics and provide new evidence that the motor and cognitive dysfunctions of schizophrenia may be related.     

Attempted eyelid closure affects intraocular pressure measurement in open-angle glaucoma patients

PURPOSE: To evaluate the effect of attempted eyelid closure on intraocular pressure (IOP) measurements in normal-tension (NTG) and high-tension (HTG) open-angle glaucoma patients. DESIGN: Prospective clinical trial. METHODS: Forty randomly selected eyes of 40 patients underwent corneal pachymetry and IOP measurements using both Goldmann applanation tonometry and Tono-pen XL (Mentor, Inc., Norwell, Massachusetts, USA). Intraocular pressure was measured by the same examiner holding the eyelids open, both with and without the subject simultaneously attempting forced eyelid closure. Subjects were seated during all measurements and waited 5 minutes between measurements with each instrument; the order of measurement was randomized. RESULTS: Twenty NTG and 20 HTG eyes were enrolled. The mean age was 63.0 +/- 13.0 years (range, 31-80 years). The average corneal thickness was 540 +/- 32 microm (range, 480-608 microm) in NTG patients and 552 +/- 40 microm (range, 449-610 microm) in HTG patients (P =.07, analysis of variance [ANOVA]). Using Goldmann applanation tonometry, IOP measurement in eyes with NTG increased by 3.9 +/- 2.0 mm Hg with attempted eyelid closure (P <.0001, paired t test; range, 2-11 mm Hg). With the Tono-pen XL, IOP measurements increased 4.2 +/- 2.7 mm Hg (P <.0001, paired t test; range, 1-14 mm Hg). With attempted forced eyelid closure, the Goldmann applanation measurement in eyes with HTG increased 4.1 +/- 2.1 mm Hg (P <.0001, paired t test; range, 1-9 mm Hg). Using the Tono-pen XL, measurements increased 4.5 +/- 2.0 mm Hg (P <.0001, paired t test; range, 2-11 mm Hg). CONCLUSION: Attempted eyelid closure during tonometry is a significant and common source of error in eyes with glaucoma and may influence the clinical management and decision-making in the treatment of NTG and HTG.