Nystagmus Amplitude Research Articles

Exploring Eye Movement Features of Motion Sickness Using Closed-Track Driving Experiments.

To explore and validate effective eye movement features related to motion sickness (MS) through closed-track experiments and to provide valuable insights for practical applications. With the development of autonomous vehicles (AVs), MS has attracted more and more attention. Eye movements have great potential to evaluate the severity of MS as an objective quantitative indicator of vestibular function. Eye movement signals can be easily and noninvasively collected using a camera, which will not cause discomfort or disturbance to passengers, thus making it highly applicable. Eye movement data were collected from 72 participants susceptible to MS in closed-track driving environments. We extracted features including blink rate (BR), total number of fixations (TNF), total duration of fixations (TDF), mean duration of fixations (MDF), saccade amplitude (SA), saccade duration (SD), and number of nystagmus (NN). The statistical method and multivariate long short-term memory fully convolutional network (MLSTM-FCN) were used to validate the effectiveness of eye movement features. Significant differences were shown in the extracted eye movement features across different levels of MS through statistical analysis. The MLSTM-FCN model achieved an accuracy of 91.37% for MS detection and 88.51% for prediction in binary classification. For ternary classification, it achieved an accuracy of 80.54% for MS detection and 80.11% for prediction. Evaluating MS through eye movements is effective. The MLSTM-FCN model based on eye movements can efficiently detect and predict MS. This work can be used to provide a possible indication and early warning for MS.

Audiometric and Vestibular Function after Classic and Reverse Stapedotomy.

Background and Objectives: Besides classical stapedotomy, reverse stapedotomy has been used for many years in the management of otosclerosis. Our study aims to investigate whether reversing the surgical steps in stapedotomy impacts vestibular function and hearing improvement. Materials and Methods: A cohort of 123 patients underwent either classic or reverse stapedotomy procedures utilizing a fiber-optic argon laser. Audiological assessments, following the guidelines of the Committee on Hearing and Equilibrium, were conducted, including pure tone average, air-bone (AB) gap, overclosure, and AB gap closure. Vestibular evaluation involved pre- and postoperative comparison of rotatory test parameters, including frequency, amplitude, and slow phase velocity of nystagmus. Results: The study demonstrated an overall median overclosure of 3.3 (3.3, 5.0) dB and a mean AB gap closure of 20.3 ± 8.8 dB. Postoperative median AB gap was 7.5 (7.5, 11.3) dB in the reverse stapedotomy group and 10.0 (10.0, 12.5) dB in the classic stapedotomy group. While overclosure and AB gap closure were marginally superior in the reverse stapedotomy group, these differences did not reach statistical significance. No significant disparities were observed in the frequency, slow phase velocity, or amplitude of nystagmus in the rotational test. Conclusions: Although not always possible, reverse stapedotomy proved to be a safe surgical technique regarding postoperative outcomes. Its adoption may mitigate risks associated with floating footplate, sensorineural hearing loss, and incus luxation/subluxation, while facilitating the learning curve for less experienced ear surgeons.

Clinical Assessment of the Nystagmus Fixation Suppression Test: An Experimental Study.

Assessment of nystagmus fixation suppression can be used as an additional diagnostic tool for patients with an acute vestibular syndrome to distinguish between a central or peripheral cause. We investigated the ability of physicians to detect fixation suppression using a nystagmus simulation model. We used a nystagmus simulator to measure the accuracy of the nystagmus fixation suppression test. Fixation suppression was assessed randomly in 6170 trials by 20 otorhinolaryngologists and neurologists, segregated into 2 groups based on their neurootological experience, a beginner and an experienced group. The simulator presented random nystagmus slow velocity (SPV) reductions and presented 3 conditions with either changed nystagmus frequency, amplitude, or both. The cutoff for the discernment of fixation suppression ranged from 1.2 to 14°/s nystagmus velocity difference. The more intense the baseline nystagmus was, the more difficult was the detection of fixation suppression. There was not significant difference (P >.05) in the cutoff values in the experts group compared to the novices for all 3 different conditions. Both, novices and experts, detected frequency changes easier than differences of the nystagmus amplitude. Test sensitivity was very low (19%-65%) for discernment of small nystagmus velocity differences of <2°/s by experts. In our study, there was no difference between experts and novices in detection of nystagmus suppression by visual fixation. The examiners could only detect large suppression effects at low-intensity baseline nystagmus. Overall, the sensitivity and accuracy of a clinical fixation suppression test is low and the assistance with a video-oculography device is highly recommended.

Nystagmus Characteristics in Albinism: Unveiling the Link to Foveal Hypoplasia and Visual Acuity.

The purpose of this study was to describe the association among nystagmus characteristics, foveal hypoplasia, and visual acuity in patients with albinism. We studied nystagmus recordings of 50 patients with albinism. The nystagmus waveform was decomposed into two types: dominantly pendular and dominantly jerk. We correlated the nystagmus type, amplitude, frequency, and percentage of low velocity (PLOV) to Snellen visual acuity and foveal hypoplasia grades. The grade of foveal hypoplasia and visual acuity showed a strong correlation (r = 0.87, P < 0.0001). Nystagmus type and PLOV had the strongest significant (P < 0.0001) correlation with visual acuity (r = 0.70 and r = -0.56, respectively) and with foveal hypoplasia (r = 0.76 and r = -0.60, respectively). Patients with pendular nystagmus type had the lowest PLOV, and the highest grade of foveal hypoplasia (P < 0.0001). Severe foveal hypoplasia (grade 4), was almost invariably associated with pendular nystagmus (86%). Foveal hypoplasia grade 4 is associated with pendular nystagmus, lower PLOV, and worse visual acuity. Based on these results, nystagmus recordings at a young age may contribute to predicting visual outcomes.

Analysis of Suspected Achromatopsia by Multimodal Diagnostic Testing.

Abstract Background Achromatopsia (ACHM) as a hereditary cone disease might manifest in a stationary and progressive manner. The proper clinical and genetic diagnosis may allow an individual prognosis, accurate genetic counselling, and the optimal choice of low vision aids. The primary aim of the study was to determine the spectrum of clinical and genetic diagnostics required to characterize the ACHM. Methods A retrospective analysis was performed in 8 patients from non-related families (5 ♀,3 ♂); age at diagnosis: 3 – 56 y, mean 18.13 (SD ± 18.22). Clinical phenotyping, supported by colour vision test, fundus photography-, autofluorescence- (FAF), infra-red- (IR), OCT imaging and electroretinography provided information on the current status and the course of the disease over the years. In addition, genetic examinations were performed with ACHM relevant testing (CNGA3, CNGB3, GNAT2, PDE6C, PDE6H and the transcription factor ATF6). Results All patients suffered photophobia and reduced visual acuity (mean: 0.16 [SD ± 0.08]). Nystagmus was identified in 7 from 8 subjects and in one patient a head-turn right helped to reduce the nystagmus amplitude. Colour vision testing confirmed complete achromatopsia in 7 out of 8 patients. Electrophysiology found severely reduced photopic- but also scotopic responses. Thinning and interruption of the inner segment ellipsoid (ISe) line within the macula but also FAF- and IR abnormalities in the fovea and/or parafovea were characteristic in all ACHM patients. Identification of pathogenic mutations in 7 patients helped to confirm the diagnosis of ACHM (3 adults, 4 children; 3 ♀ and 4 ♂). Achromatopsia was linked to CNGA3 (2 ♀, 1 ♂) and CNGB3 variants (2 ♀, 3 ♂). The youngest patient (♀, 10 y) had 3 different CNGB3 variants on different alleles. In a patient (♂, 29 y) carrying 2 pathogenic digenic-triallelic CNGA3- and CNGB3-mutations, a severe progression of ISe discontinuity to coloboma-like macular atrophy was observed during the 12-year follow-up. The oldest female (67 y) showed a compound homozygous CNGA3- and heterozygous CNGB3-, as well as a heterozygous GUCY2D variants. The destruction of her ISe line was significantly enlarged and represented a progressive cone-rod phenotype in comparison to other ACHM patients. In a patient (♂, 45 y) carrying a pathogenic CNGB3 and USH2 mutation, a severe macular oedema and a rod-cone phenotype was observed. In addition, two variants in C2ORF71 considered as VOS were found. One patient showed the rare ATF6 mutation, where a severe coloboma-like macular atrophy was observed on the left eye as early as at the age of three years. Conclusion Combining multimodal ophthalmological diagnostics and molecular genetics when evaluating patients with ACHM helps in characterizing the disease and associated modifiers, and is therefore strongly recommended for such patients.

Mathematical Justification of the Sports Selection of Jumpers in the Water at the Stage of Initial Training

The relevance of the problem is determined by the fact that an athlete who possesses genetic and physiological abilities that were discovered in time can master a complex jumping program and execute it without error at a high technical level. Therefore, it is important to mathematically substantiate the criteria for selecting children in sports schools. The Purpose of the Study: To determine indicators affecting sports readiness, to calculate their prognostic significance and to form criteria for the selection of jumpers in the water at the stage of initial training. Material and Methods: The research was organized in three stages in the period from January 2020 to December 2021, with the determination of the normative assessment of technical readiness, the conduct of an ascertaining pedagogical experiment and factor analysis, the calculation of multiple regression equations relative to the total coefficient of difficulty of arbitrary jumps and the average coefficient of the complexity of jumps. 139 boys (10,98±0,1 years; range: 9–13 years) and 96 girls (11,02±0,1 years; range: 9–13 years) beginners (schoolchildren) took part in the study. The number of athletes is divided by age groups: boys – 9 years old (n=25); 10 years (n = 30); 11 years (n = 30); 12 years (n = 31); 13 years old (n = 23); girls – 9 years old (n=16); 10 years (n=23); 11 years (n=18); 12 years (n=21); 13 years old (n=18). The study was organized and carried out with athletes of the Junior High School (Lviv) and «Yantar» Junior High School (Novoyavorivsk). During the educational and training meetings, testing and measuring of anthropometric indicators, determination of the speed of a simple sensorimotor reaction and conscious self-regulation of sensorimotor activity, research of vestibular stability were carried out. All measurements were taken before training in the morning and in the afternoon at 9:00 and 15:00. Results: According to the results of the study, the indicators that have prognostic significance for the success of the sport's improvement of young jumpers at the stage of improving their sports training have been determined. To these indicators, we included: the total indicator of physical fitness, the amplitude of nystagmus during and after turning to the right, the speed of a simple motor reaction. The comprehensive assessment obtained by calculating multiple regression equations has a high prognostic value and is an effective method of predicting the success of the sport's improvement of young jumpers at the stage of initial sports training. Conclusions. It is proved that the comprehensive assessment obtained by calculating multiple regression equations has a high prognostic value and is an effective method of predicting the success of the sport's improvement of young jumpers at the stage of initial sports training.

Mathematical Justification of the Sports Selection of Jumpers in the Water at the Stage of Initial Training

The relevance of the issue is determined by the fact that an athlete possessing genetic and physiological abilities that were discovered in time can master a complex jumping program and execute it excellently at a high technical level. Therefore, it is important to mathematically substantiate the criteria for children enrollment to the sports schools. The Purpose of the Study is to determine indicators affecting sports readiness, to calculate their prognostic significance and to form criteria for the selection of jumpers into the water at the stage of initial training. Stuff Material and Methods. The research was organized over three stages in the period from January 2020 to December 2021, with the determination of the normative assessment of technical readiness, the conduct of an ascertaining pedagogical experiment and factor analysis, the calculation of multiple regression equations relative to the total coefficient of difficulty of arbitrary jumps and the average coefficient of the complexity of jumps. 139 boys (10,98±0,1 years; range: 9–13 years) and 96 girls (11,02±0,1 years; range: 9–13 years) beginners (schoolchildren) took part in the study. The number of athletes is divided by age groups: boys – 9 years old (n=25); 10 years (n = 30); 11 years (n = 30); 12 years (n&#x0D; = 31); 13 years old (n = 23); girls – 9 years old (n=16); 10 years (n=23); 11 years (n=18); 12 years (n=21); 13 years old (n=18). The study was organized and carried out with athletes of the Junior High School (Lviv) and Yantar Junior High School (Novoyavorivsk). During the educational and training meetings, testing and measuring of anthropometric indicators, determination of the speed of a simple sensorimotor reaction and conscious self-regulation of sensorimotor activity, research of vestibular stability were carried out. All measurements were taken before training in the morning and in the afternoon at 9:00 and 15:00. According to the Results of the Research, the indicators that have prognostic significance for the success of the sport`s improvement of young jumpers at the stage of improving their sports training have been determined. The total indicators of physical fitness, the nystagmus amplitude during and after turning to the right, the speed of a simple motor reaction have been included. The comprehensive assessment obtained by calculating multiple regression equations has a high prognostic value and is an effective method of predicting the success of the sport`s improvement of young jumpers at the stage of initial sports training. Conclusions. It is proved that the comprehensive assessment obtained by calculating multiple regression equations has a high prognostic value and is an effective method of predicting the success of the sport`s improvement of young jumpers at the initial sports training stage.

A 6-month trial of memantine for nystagmus and associated phenomena in oculopalatal tremor.

IntroductionOculopalatal tremor (OPT) is a late manifestation of a Guillain-Mollaret triangle lesion. Memantine has been shown to improve nystagmus in OPT, but its long-term efficacy and putative distinct effects on each plane of nystagmus and on associated phenomena (e.g., gravity perception) are largely unknown.MethodsWe conducted a 6-month open-label study to evaluate the effect of memantine in OPT patients. Baseline (visit 1), 2 (visit 2), and 6 months (visit 3) assessments included video-oculography, best corrected visual acuity (BCVA), visual function questionnaire (VFQ25), palatal tremor frequency, and subjective visual vertical (SVV). Memantine was titrated to 20 mg per day and stopped after 6 months.ResultsWe included six patients (5 females; mean age 68.5+/-9.7). At visit 2, nystagmus improved >50% only along the horizontal plane in two patients, while worsening >50% along the vertical and horizontal planes in 4 and 1 patients, respectively. At visit 3, previous improvement of nystagmus along the horizontal plane in two patients was not sustained, and it further worsened >50% along the vertical plane in 4. The mean vertical velocity and amplitude of nystagmus in the left eye significantly worsened from visit 2 to visit 3 (p = 0.028). Throughout the study, nystagmus frequency remained unchanged (p = 0.074), BCVA improved in both eyes (p = 0.047, p = 0.017), SVV progression was unpredictable (p = 0.513), and the mean VFQ-25 score (p = 0.223) and mean palatal frequency remained unchanged.ConclusionThe long-term use of memantine 20 mg per day in OPT produced a modest and only transient improvement in nystagmus, predominantly along the horizontal plane. Visual acuity improved, albeit without relevant changes in vision-related quality of life.

Effect of Acupuncture on Waveform Characteristics and Visual Acuity in Idiopathic Infantile Nystagmus: A Prospective Interventional Study

Introduction: Idiopathic Infantile Nystagmus or Infantile Nystagmus Syndrome (INS) is one of the known causes for congenital nystagmus. Though the exact aetiology is unknown, there have been studies related to its treatment using prisms and contact lens. However, there have been not many clinical studies using the alternative therapy like acupuncture is done to analyse the effect on nystagmus. Therefore, the rationale of the study was to know the effect of acupuncture in INS and identify the same by Videonystagmography (VNG). Aim: To evaluate the effect of acupuncture on waveform characteristics and visual acuity in INS. Materials and Methods: This prospective interventional study was performed at Dr. Rajendra Prasad Centre for Ophthalmic Sciences, AIIMS, New Delhi, India, during the period of March 2004 to March 2006. Institutional review board/ethical clearance was obtained and patients with INS of more than 18 years, who were co-operative, underwent acupuncture needle stimulation of sternocleidomastoid. The needles in sternocleidomastoid were stimulated every 5 minutes for 15 minutes for 10 sittings (5 days). Nystagmus parameters like slow phase velocity, amplitude, frequency were recorded by videonystagmograpy for 20 minutes. Changes in waveform and visual acuity (Snellen visual acuity charts) were examined on every visit on all five days and patients were followed-up for three months. Visual acuity, nystagmus intensity, amplitude, frequency and slow phase velocity were the parameters analysed. A repeated measure- Analysis of Variance (ANOVA) test and Freidman test was performed using Statistical Package for the Social Sciences (SPSS) (version 16.1) to analyse the data. A p-value &lt;0.05 was considered significant. Results: Ten patients with INS underwent the procedure. Significant improvement in distant visual acuity was noted at three months (right eye p=0.039, left eye p=0.050). Significant decrease in frequency during treatment (p=0.046, p=0.014 at 10 minutes and 15 minutes respectively) was noted. Dampening of nystagmus amplitude was seen during acupuncture therapy, which got enhanced by twirling of the needles. No permanent changes in waveform characteristics were seen after therapy in the follow-up for over three months. Conclusion: The afferent stimulation from neck muscles by acupuncture in infantile nystagmus does affect waveforms during therapy and visual acuity after the therapy on short-term.

Refractive changes with post-rotatory nystagmus in healthy individuals.

Post-rotatory nystagmus has been used to detect autism spectrum disorders in clinical settings. Although previous studies have focused on eye movements, they did not evaluate the change in ocular refraction during post-rotatory nystagmus. This study aimed to evaluate the changes in ocular refraction during post-rotatory nystagmus in healthy individuals. A total of 34 healthy volunteers (mean age ± standard deviation, 20.9 ± 0.6years) participated in this study. The ocular refraction during post-rotatory nystagmus was measured using MR-6000 (Tomey Inc.) on quick mode with a sampling rate of 30Hz under noncycloplegic and cycloplegic conditions. The amplitude of post-rotatory nystagmus was calculated on the basis of the anterior eye images, while the ocular refraction measurements were simultaneously recorded. The accommodative convergence per accommodation ratio was calculated using the heterophoria method. Video oculography was performed to measure the angle of convergence during post-rotatory nystagmus. The changes in ocular refraction during post-rotatory nystagmus were significantly greater under the noncycloplegic condition than under the cycloplegic condition. The changes in ocular refraction during the post-rotatory nystagmus were significantly and positively correlated with the amplitude of post-rotatory nystagmus under the noncycloplegic condition. The angle of convergence during post-rotatory nystagmus was significantly higher under the noncycloplegic condition than under the cycloplegic condition. The changes in the angle of convergence were significantly and positively correlated with the predicted accommodative convergence. These findings suggest that the accommodation was functional during the post-rotatory nystagmus to compensate for the retinal image slip, and the accommodative convergence can help weaken the nystagmus.

Machine learning models for the prediction of acuity and variability of eye-positioning using features extracted from oculography

During the first months of life, babies can be affected by congenital nystagmus, an ocular-motor disease making visual acuity decrease. Electrooculography (EOG) and Infrared-oculography are utilized in order to perform eye-tracking of patients, giving the possibility to extract from the signals several useful features. In the past years, different algorithms were used to perform the detection of events on these features and many researchers studied the relationships between the features and physiological values such as visual acuity and variability of eye-positioning. In this paper, machine learning techniques were used to predict visual acuity and the variability of eye positioning using features extracted from EOG. The EOG of 20 patients was acquired, signals underwent a pre-processing, and some parameters were extracted through a custom-made software. Frequency, amplitude, intensity, nystagmus foveation periods and both amplitude and frequency of baseline oscillation were the features used as input for the algorithms. Knime analytics platform was employed to perform a predictive analysis using Random Forests, Logistic Regression Tree, Gradient boosted tree, K nearest neighbour, Multilayer Perceptron and Support Vector Machine. Finally, some evaluation metrics were computed employing a leave one out cross validation. Considering the coefficient of determination, visual acuity achieved values between 0.67 and 0.85 while variability of eye positioning ranged from 0.62 to 0.79. These results were compared with past analysis with the exact same aims and dataset, obtaining a greater value as regards the variability of eye positioning and comparable results exploiting all the features related to nystagmus as regards the visual acuity. This paper showed the feasibility of a regression analysis performed through machine learning algorithms in detecting relationships among variables related to congenital nystagmus.

The efficacy of low vision aids with contact lenses in pediatric population.

To compare the efficacy of contact lens use with low vision aids (LVA) with the efficacy of spectacle use with low vision aids. Thirty-six pediatric patients with low vision were enrolled in this study between January 2015 and March 2017. The patients were examined for best-corrected visual acuity (BCVA) with spectacles, spectacles with LVA, contact lenses and contact lenses with LVA. Toleration of the patients with contact lenses and LVA were recorded at the final follow-up exam. The mean BCVA with spectacles was detected as 1.11 ± 0.25 log MAR and the mean BCVA improved to 0.35 ± 0.13 log MAR with the use of spectacles and LVA, which was statistically significant. The mean BCVA with contact lens, which was 0.99 ± 0.22 log MAR, improved to 0.40 ± 0.21 log MAR with contact lens and LVA, which was also significant. There was a statistically significant improvement in BCVA of the patients with contact lenses only when compared to spectacles only. The mean BCVA significantly improved in patients using LVA with contact lenses when compared to LVA with spectacles. Tolerations of the patients with contact lenses and LVA were found to be well at 29 of 36 (80.55%) at final follow-up (26.11 ± 6.85 months). Contact lens use in pediatric patients with low vision especially with LVA offers better visual acuity, a decrease in nystagmus amplitude, wider field of view and comfort.

Gabapentin and Memantine for Treatment of Acquired Pendular Nystagmus: Effects on Visual Outcomes.

The most common causes of acquired pendular nystagmus (APN) are multiple sclerosis (MS) and oculopalatal tremor (OPT), both of which result in poor visual quality of life. The objective of our study was to evaluate the effects of memantine and gabapentin treatments on visual function. We also sought to correlate visual outcomes with ocular motor measures and to describe the side effects of our treatments. This study was single-center cross-over trial. A total of 16 patients with chronic pendular nystagmus, 10 with MS and 6 with OPT were enrolled. Visual acuity (in logarithm of the minimum angle of resolution [LogMAR]), oscillopsia amplitude and direction, eye movement recordings, and visual function questionnaires (25-Item National Eye Institute Visual Functioning Questionnaire [NEI-VFQ-25]) were performed before and during the treatments (gabapentin: 300 mg 4 times a day and memantine: 10 mg 4 times a day). A total of 29 eyes with nystagmus were evaluated. Median near monocular visual acuity improved in both treatment arms, by 0.18 LogMAR on memantine and 0.12 LogMAR on gabapentin. Distance oscillopsia improved on memantine and on gabapentin. Median near oscillopsia did not significantly change on memantine or gabapentin. Significant improvement in ocular motor parameters was observed on both treatments. Because of side effects, 18.8% of patients discontinued memantine treatment-one of them for a serious adverse event. Only 6.7% of patients discontinued gabapentin. Baseline near oscillopsia was greater among those with higher nystagmus amplitude and velocity. This study demonstrated that both memantine and gabapentin reduce APN, improving functional visual outcomes. Gabapentin showed a better tolerability, suggesting that this agent should be used as a first-line agent for APN. Data from our investigation emphasize the importance of visual functional outcome evaluations in clinical trials for APN.

Myectomy of the four horizontal rectus muscles with pulley fixation for the treatment of horizontal nystagmus in 10 adults: a pilot study

Myectomy and release of the four horizontal rectus muscles can ameliorate nystagmus, but may result in adduction limitation, convergence insufficiency, or exotropia. We developed a modified four-muscle myectomy with pulley fixation, in which the myectomized muscles are attached to the pulley rather than released. The purpose of this study was to present a prospective review of the clinical, nystagmographic, and quality-of-life data in a cohort of adults. Ten adults with horizontal infantile nystagmus syndrome were recruited between July 2018 and October 2018. Subjects were grouped according to presence or absence of foveal hypoplasia (FH). Following myectomy, all four horizontal rectus muscles were sutured within the pulley or encircling fascia. All participants completed a comprehensive sensorimotor examination, videonystagmography, and a nystagmus-specific quality-of-life questionnaire. Of the 10 subjects, 5 were in the FH group and 5 in the no-FH group. Postoperatively, all 10 subjects experienced an improved quality of life, with median increases of 73% (FH) and 104% (No-FH). Nystagmus amplitude and slow-phase velocity were reduced, and binocular best-corrected visual acuity improved in both groups. Foveation time increased, but inconsistently, within subjects and between groups. Horizontal ocular rotations were reduced by up to 58%. Five subjects required transposition surgery for symptomatic exotropia (4) or hypertropia (1). In this small study cohort, four-muscle myectomy with pulley fixation reduced the amplitude and velocity of nystagmus and improved quality of life and visual acuity, notwithstanding reduced ocular rotation and reoperation. Fixation of the muscle to the pulley did not reduce the risk of exotropia.

Clinical Characteristics of Acute Vestibular Neuritis According to Involvement Site.

To analyze the clinical characteristics of acute vestibular neuritis (AVN) according to involvement site. Retrospective chart analysis. Tertiary referral hospital. Over a period of 3 years, we reviewed 133 cases of AVN. Patients were classified into three groups: 1) total vestibular neuritis (superior and inferior vestibular nerve involvement [TVN]); 2) superior vestibular neuritis (superior vestibular nerve involvement [SVN]); and 3) inferior vestibular neuritis (inferior vestibular nerve involvement [IVN]). We analyzed the clinical course and results of vestibular function tests (video-nystagmography, video head impulse test [vHIT], caloric test, and cervical vestibular evoked myogenic potential). In the study, there were 39.9% TVN cases, 48.1% SVN cases, and 12% IVN cases. The number of days to spontaneous nystagmus remission, hospital duration, and follow-up period were shorter in the IVN group than in the SVN and TVN groups. The symptom onset period was longer in the IVN group than in the SVN and TVN groups. Spontaneous nystagmus and head shaking nystagmus amplitude were smaller in the IVN group than in the SVN and TVN groups. Concordance of results between the caloric test, cervical vestibular evoked myogenic potential, and vHIT was relatively low in the IVN group. The IVN group had a shorter clinical course and weaker nystagmus in comparison with the TVN and SVN groups. The use of additional vHIT in the diagnosis of AVN can help provide a more accurate diagnosis of the rare subtype of IVN, which can be confused with various central lesions.

Application of horizontal rectus muscle suture clamp for the treatment of congenital nystagmus without intermediate band

Objective To evaluate the efficacy of application of horizontal rectus muscle suture clamp for the treatment of congenital nystagmus (CN) without intermediate band. Methods The data of 11 patients with no intermediate band CN from Jan.2016 to Jun.2017 were retrospectively analyzed. All cases received the self designed surgery of horizontal rectus muscle suture clamp. The visual acuity(LogMAR), the amplitude and frequency of nystagmus before and after operation were summarized. Results The best corrected visual acuity of right eye before and 1, 3 months after operation were 0.65±0.25, 0.42±0.26 and 0.38±0.23, respectively. Those of left eye were 0.62±0.26, 0.38±0.17 and 0.35±0.14, respectively. The postoperative best corrected visual acuity at 1 and 3 months of binocular were improved (P<0.05). The amplitude and frequency of nystagmus at 3 months after operation were decreased. The difference was statistically significant between before and after operation (P<0.05). Conclusion Horizontal rectus muscle suture clamp for the treatment of CN without intermediate band can effectively decrease amplitude and frequency of nystagmus, and significantly improve visual function. Key words: Nystagmus, congenital, without intermediate band; Suture, clamp

Effect of Gabapentin/Memantine on the Infantile Nystagmus Syndrome in the Zebrafish Model: Implications for the Therapy of Ocular Motor Diseases.

Infantile nystagmus syndrome (INS) is a disorder characterized by typical horizontal eye oscillations. Due to the uncertain etiology of INS, developing specific treatments remains difficult. Single reports demonstrated, on limited measures, alleviating effects of gabapentin and memantine. In the current study, we employed the zebrafish INS model belladonna (bel) to conduct an in-depth study of how gabapentin and memantine interventions alleviate INS signs, which may further restore visual conditions in affected subjects. Moreover, we described the influence of both medications on ocular motor functions in healthy zebrafish, evaluating possible iatrogenic effects. Ocular motor function and INS characteristics were assessed by eliciting optokinetic response, spontaneous nystagmus, and spontaneous saccades in light and in dark, in 5- to 6-day postfertilization bel larvae and heterozygous siblings. Single larvae were recorded before and after a 1-hour drug treatment (200 mM gabapentin/0.2 mM memantine). Both interventions significantly reduced nystagmus intensity (gabapentin: 59.98%, memantine: 39.59%). However, while the application of gabapentin affected all tested ocular motor functions, memantine specifically reduced nystagmus amplitude and intensity, and thus left controls completely unaffected. Finally, both drug treatments resulted in specific changes in nystagmus waveform and velocity. Our study provides deeper insight into gabapentin and memantine treatment effect in the zebrafish INS model. Moreover, this study should establish zebrafish as a pharmacologic animal model for treating nystagmus and ocular motor disease, serving as a basis for future large-scale drug screenings.

Clinical feature and waveform in infantile nystagmus syndrome in children with FRMD7 gene mutations.

Infant nystagmus sydrome presents as involuntary eye movement disorder and can affect seriously ocular function. We performed a retrospective study of clinical data and FRMD7 genetic test results in 12 cases of infantile nystagmus syndrome to correlate waveform, stereopsis, and visual acuity. The patients (age 6.40±2.67 years) had FRMD7 mutations as follows: missense in eight cases, shear in two cases, frameshift in one case, and non-frameshift in one case. Horizontal jerk waveform was observed in six cases, versus horizontal pendulum in five cases and dual jerk in one case. The uncorrected visual acuity (24 eyes) was 0.21±0.12, compared with a corrected visual acuity (24 eyes) of 0.32±0.14. All patients had simultaneous perception, versus fusion function in 10 cases (83.33%) and stereoscopic vision in seven cases (58.33%) using the synoptophore. Eleven cases (91.67%) detected the stereo fly, compared with five cases (41.67%) for stereoscopic circles and seven cases (58.33%) for stereoscopic animals by Titmus test. Stereoscopic vision using the synoptophore did not correlate with the frequency, amplitude, or intensity of nystagmus or with corrected binocular visual acuity. The infantile nystagmus syndrome with FRMD7 mutations in our cases was caused primarily de novo and missense mutations. Visual acuity and binocular visual function were significant impaired, and the waveform was generally horizontal jerk. Also, an infrared videonystagmogram can record the frequency, amplitude, and intensity of nystagmus accurately.

The Effect of Gaze Angle on Visual Acuity in Infantile Nystagmus.

Most individuals with infantile nystagmus (IN) have an idiosyncratic gaze angle at which their nystagmus intensity is minimized. Some adopt an abnormal head posture to use this "null zone," and it has therefore long been assumed that this provides people with nystagmus with improved visual acuity (VA). However, recent studies suggest that improving the nystagmus waveform could have little, if any, influence on VA; that is, VA is fundamentally limited in IN. Here, we examined the impact of the null zone on VA. Visual acuity was measured in eight adults with IN using a psychophysical staircase procedure with reversals at three horizontal gaze angles, including the null zone. As expected, changes in gaze angle affected nystagmus amplitude, frequency, foveation duration, and variability of intercycle foveation position. Across participants, each parameter (except frequency) was significantly correlated with VA. Within any given individual, there was a small but significant improvement in VA (0.08 logMAR) at the null zone as compared with the other gaze angles tested. Despite this, no change in any of the nystagmus waveform parameters was significantly associated with changes in VA within individuals. A strong relationship between VA and nystagmus characteristics exists between individuals with IN. Although significant, the improvement in VA observed within individuals at the null zone is much smaller than might be expected from the occasionally large variations in intensity and foveation dynamics (and anecdotal patient reports of improved vision), suggesting that improvement of other aspects of visual performance may also encourage use of the null zone.

Effect of Rigid Gas Permeable Contact Lenses on Nystagmus and Visual Function in Hyperopic Patients with Infantile Nystagmus Syndrome

ABSTRACTPurpose: To determine the effect of rigid gas permeable contact lenses (RGPCL) on involuntary eye movements and visual function in hyperopic patients with infantile nystagmus syndrome. Methods: This prospective interventional case series was conducted on 16 patients with infantile nystagmus and hyperopia equal or more than +0.5 D and astigmatism more than -1 D over a 2-year period. A complete ophthalmological examination including determination of best corrected visual acuity (BCVA), contrast sensitivity, and videonystagmography was performed for all patients before and after at least 3 months of RGPCL use, and the outcomes were compared. Results: Thirty-two eyes of 16 patients with mean age of 18.6±4.9 years were enrolled. Mean spherical equivalent refractive error was +1.5±2.35 (range +1 to +6.25) diopters (D); corresponding values were +2.45±2.44 D (range +0.5 to +7.5) for spherical error and +1.90±0.83 D (range +1 to +4) for astigmatism. Monocular BCVA improved from 0.56±0.23 to 0.51±0.23 Log MAR (P=0.007), and binocular BCVA improved from 0.54±0.25 to 0.48±0.24 Log MAR (P=0.01) after fitting RGPCL. Following the use of RGPCL, contrast sensitivity was significantly improved at low (P=0.02) and intermediate (P< 0.001) frequencies but not at high frequencies (P=0.6). The frequency, amplitude, and intensity of nystagmus were decreased significantly after RGPCL use (P<0.001). Conclusion: RGPCL improved monocular and binocular BCVA and contrast sensitivity in hyperopic patients with infantile nystagmus syndrome. Motor indices of nystagmus (frequency, amplitude, and intensity) were also significantly improved after RGPCL use.