ArticleLiterature Review

Surgical interventions for infantile nystagmus syndrome

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Abstract

Background: Infantile nystagmus syndrome (INS) is a type of eye movement disorder that can negatively impact vision. Currently, INS cannot be cured, but its effects can potentially be treated pharmacologically, optically, or surgically. This review focuses on the surgical interventions for INS. Despite the range of surgical interventions available, and currently applied in practice for the management of INS, there is no clear consensus, and no accepted clinical guidelines regarding the relative efficacy and safety of the various treatment options. A better understanding of these surgical options, along with their associated side effects, will assist clinicians in evidence-based decision-making in relation to the management of INS. Objectives: To assess the efficacy and safety of surgical interventions for INS. Search methods: We searched CENTRAL, MEDLINE Ovid, Embase Ovid, ISRCTN registry, ClinicalTrials.gov, and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) to 3 July 2020, with no language restrictions. Selection criteria: We included randomised controlled trials (RCTs) studying the efficacy and safety of surgical options for treating INS. Data collection and analysis: Our prespecified outcome measures were the change from baseline in: binocular best-corrected distance visual acuity; head posture; amplitude, frequency, intensity, and foveation period durations of the nystagmus waveform; visual recognition times; quality of life and self-reported outcome measures; incidence of adverse effects with a probable causal link to treatment; and permanent adverse effects after surgery. Two review authors independently screened titles and abstracts and full-text articles, extracted data from eligible RCTs, and judged the risk of bias using the Cochrane tool. We reached consensus on any disagreements by discussion. We summarised the overall certainty of the evidence using the GRADE approach. Main results: We only identified one eligible RCT (N = 10 participants), undertaken in India. This trial randomised participants to receive either a large retro-equatorial recession of the horizontal rectus muscle of 9 mm on the medial rectus and 12 mm on the lateral rectus, or a simple tenotomy and resuturing of the four horizontal rectus muscles. We did not identify any RCTs comparing a surgical intervention for INS relative to no treatment. In the single eligible RCT, both eyes of each participant received the same intervention. The participants' age and gender were not reported, nor was information on whether participants were idiopathic or had sensory disorders. The study only included participants with null in primary position and did not explicitly exclude those with congenital periodic alternating nystagmus. The study did not report funding source(s) or author declaration of interests. The evaluation period was six months. We judged this study at low risk for sequence generation and other sources of bias, but at high risk of bias for performance and detection bias. The risk of bias was unclear for selection bias, attrition bias, and reporting bias. There is very uncertain evidence about the effect of the interventions on visual acuity and change in amplitude, frequency, and intensity of the nystagmus waveform. We were unable to calculate relative effects due to lack of data. None of the participants in either intervention group reported adverse effects at six-month follow-up (very low-certainty evidence). There was no quantitative data reported for quality of life, although the study reported an improvement in quality of life after surgery in both intervention groups (very low-certainty evidence). Change in head posture, foveation period durations of the nystagmus waveform, visual recognition times, and permanent adverse effects after surgery were not reported in the included study. We judged the certainty of the evidence, for both the primary and secondary efficacy outcomes, to be very low. Due to a lack of comprehensive reporting of adverse events, there was also very low-certainty of the safety profile of the evaluated surgical interventions in this population. As such, we are very uncertain about the relative efficacy and safety of these interventions for the surgical management of INS. Authors' conclusions: This systematic review identified minimal high-quality evidence relating to the efficacy and safety of surgical interventions for INS. The limited availability of evidence must be considered by clinicians when treating INS, particularly given these procedures are irreversible and often performed on children. More high-quality RCTs are needed to better understand the efficacy and safety profile of surgical interventions for INS. This will assist clinicians, people with INS, and their parents or caregivers to make evidence-based treatment decisions.

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Purpose To evaluate the effectiveness of a high-dose Anderson procedure (AP) to correct infantile nystagmus–related anomalous head turn (HT). Methods Twenty-nine consecutive orthotropes with infantile nystagmus with and without associated sensory defect received high-dose AP. HT was measured while the patient tried to read letters at best-corrected visual acuity (BCVA) level at 5 m and 0.3 m. BCVA, binocular vision (BV), and alignment (prism and cover test) were measured. High-dose AP with recessions of 9–16 mm was performed. All measures were taken before and 3–6 and ≥ 8 months post surgery. Success was defined by postoperative HT ≤ 10°/HT ≤ 15°. Results Medians and ranges (minimum-maximum) were:. Age at surgery was 7 years (4–44). HT at 5 m and HT at 0.3 m were 35° (20–40) and 20° (0–35), respectively. After 4 months (3–6), HT was 10° (− 3–20) and 5° (− 5–20); success rates were 74%/96% and 83%/96%. After 15 months (8–45), HT was 12° (0–20) and 6° (0–15); success rates were 46%/75% and 92%/100%; residual HT > 15° occurred in 5/9 cases with recessions < 13 mm and 1/15 cases with recessions ≥ 13 mm. With recessions ≥ 13 mm, 60% (95% confidence intervals (C.I.), 33–83%) achieved HT ≤ 10° and 93% (95% C.I. 66–99%) achieved HT ≤ 15°. Overcorrection did not occur. Anomalous head posture components in vertical and frontal planes did not improve. Residual motility was 30° (10–45). The mean BCVA improved by only 0.037 logMAR (p = 0.06). BV and ocular alignment were constant, except in 2 patients whose exophoria decompensated. Conclusions Kestenbaum surgery is a common procedure to correct infantile nystagmus–related HT. Anderson surgery is confined to bilateral yoke muscle recession; hence, less invasive but nevertheless comparably effective, high dosage is provided.
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Significance: This study compares saccades and visual task performance in patients with infantile nystagmus syndrome (INS) with that in normally sighted individuals under mental load. The results highlighted that to more completely evaluate INS therapies recognition time should also be measured with mental load, resembling real-world conditions. Purpose: Patients with INS may complain of "being slow to see." Stress is reported to worsen nystagmus and to prolong visual recognition time. We hypothesized that the effects of mental load on timing indices of visual recognition, for example, saccade latency, target acquisition time, target viewing time, and subjects' reaction time, differ between the INS and control groups. Methods: Eye movements were recorded when participants (INS group, n = 15; controls, n = 25) reported the direction of tumbling-E targets presented randomly across ±25°. The task was repeated with both mental arithmetic and time restriction to impose high mental load, confirmed through subjective ratings and heart rate measurement. Results: Mental load increased saccade latency (mean, 32.69 milliseconds; 95% confidence interval [CI], 21.17 to 44.20 milliseconds; P < .001) and target acquisition time (57.00 milliseconds; 95% CI, 34 to 81 milliseconds; P < .001). Patients with INS showed longer saccade latency (39.79 milliseconds; 95% CI, 23.98 to 55.62 milliseconds; P < .001) and target acquisition time (134.00 milliseconds; 95% CI, 96 to 172 milliseconds; P < .001) compared with controls. The interaction between task and group was significant for saccade gain (0.11; 95% CI, 0.02 to 0.19; P = .015), target acquisition time (37.93 milliseconds; 95% CI, 36.91 to 38.96 milliseconds; P = .011), and subjects' reaction time (95.37 milliseconds; 95% CI, 65.91 to 124.84 milliseconds; P = .043). There was an inverse correlation between the changes in subjects' response errors and target viewing time with mental load only for controls (r = -0.484, P = .014). Total foveation exposure time and target viewing time remained unchanged. Conclusions: Mental load worsens "being slow to see" in INS because of delayed target acquisition and possibly because efficiency of visual processing decreases more in patients with INS compared with controls. To investigate outcomes of INS therapies, visual recognition time should be also measured with mental load.
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Purpose: To report outcomes of extraocular muscle surgery to improve visual acuity or correct abnormal head posture(AHP) in patients with infantile nystagmus syndrome(INS). Subject and Methods: Twenty-two patients who underwent extraocular muscle surgery when less than 15 years old(average age at time of surgery, 7.5 years) and were followed up for at least 6 months at Hyogo College of Medicine Hospital from 2006 to 2015 were recruited. The mean followup period was 3.7 years. Large recession of all four horizontal rectus muscles was performed to reduce nystagmus. The Anderson or modified Kestenbaum methods were used to correct AHP. We retrospectively analyzed the surgical methods used to treat INS and the effects on visual acuity, AHP, and binocularity. Results: Twelve patients with a null zone, six without a null zone and jerky nystagmus, three with periodic alternating nystagmus, and one with pendular nystagmus were included. No significant improvement in postoperative binocular visual acuity was observed; however, visual acuity in the more affected eye improved significantly after surgery(p = 0.0001). Of the 11 patients with AHP, five(45%) were free from AHP and three(27%) showed improvement after surgery. Two patients exhibited recurrence of AHP. One patient with albinism and macular hypoplasia was unaffected by treatment. Binocularity did not demonstrate improvement for any type of nystagmus(near, p = 0.0845; distance, p = 0.8516). Conclusion: Extraocular muscle surgery for INS was effective in improving visual acuity in the more affected eye and AHP. However, there is a possibility that AHP could persist in patients with poor vision accompanied by macular hypoplasia.
Article
The major goal of extraocular muscle surgery for nystagmus is to reduce the abnormal head turn (AHT) which is caused by an eccentric null zone of the nystagmus. Shifting the null zone to the primary gaze position will eliminate the AHT. The Kestenbaum procedure consists of bilateral recession of the yoke muscles opposite to the AHT, combined with bilateral resection or plication of their antagonists. The Anderson procedure is confined to bilateral recession of the yoke muscles and is therefore less invasive. We report on our experience with the Anderson procedure. Patients and Methods: From September 2013 to June 2015, we performed the Anderson procedure in 11 consecutive orthotropic patients with infantile idiopathic or sensory defect nystagmus. Patients responsive to convergence inducing prisms who could benefit from artificial divergence surgery were excluded. Results: Medians and ranges (minimum-maximum) were: Age 7 years (4-30); binocular BCVA 0.5 (0.05-1.0); AHT 30° (20-40); equal recessions on the horizontal yoke muscles opposite to the AHT of 12 mm (10-17), in one case using bovine pericardium grafts. Three (3-6) months post surgery, the AHT was reduced to 7° (0-20). First step success rates, defined by residual AHT ≤ 10° and ≤ 15°, were 73 % (95 % CI 39-93 %) and 82 % (95 % CI 48-97 %). No over-correction or other adverse effects were observed. Two patients later received augmenting surgery. One patient with pre-existing exophoria later required strabismus surgery for exotropia. Conclusion: The AHT can be significantly reduced or completely corrected by the Anderson procedure. Recessions of at least 10 mm on both yoke muscles were performed. The success rates equaled success rates of augmented Kestenbaum surgery. Compared to the latter, the Anderson procedure is less invasive. It is followed by a shorter healing process. It is a vessel sparing method - an advantage for potential future surgery. Georg Thieme Verlag KG Stuttgart · New York.
Article
Purpose: To report the comparative clinical findings for two nystagmus procedures in two consecutive case series: the Sinskey anterior extirpation procedure (SAEP) and a modification, myectomy without reattachment (MWR). Methods: Twenty consecutive patients underwent the SAEP and 19 underwent MWR. The SAEP is a snare-assisted unmeasured deep myectomy, whereas MWR is a measured myectomy at posterior Tenon's fascia. All patients underwent comprehensive ophthalmologic and orthoptic examination with infrared videonystagmography. Binocular best corrected visual acuity, nystagmus amplitude, alignment, and versions outcomes were measured. Results: The highest percentage of patients experiencing two or more lines of improvement in distance and near acuity was in the SAEP group, who were younger than 10 years and had no ocular comorbidity (100%). Distance and near acuity improved at least one line in 71% and 86% of patients in the SAEP group and 72% and 61% in the MWR group, respectively. In both groups, patients younger than 10 years had the best acuity gains. Average nystagmus amplitude was reduced 76.3% (SAEP) and 68% (MWR). Horizontal versions were more compromised in the SAEP group and one patient experienced intraoperative orbital bleeding. Patients requiring reoperation for strabismus numbered 5 of 20 (20%) in the SAEP and 3 of 19 (16%) in the MWR groups. Conclusions: Similar to SAEP, the MWR procedure reduces nystagmus amplitudes and improves visual acuity but with less limitation of versions, risk of intraoperative bleeding, and risk of postoperative strabismus. Data suggest that early surgery (for patients younger than 10 years) can have a greater beneficial effect on postoperative visual acuity. [J Pediatr Ophthalmol Strabismus. 2016;53(3):156-166.].
Chapter
Genaue Messungen der Augenbewegungen an 100 Personen mit kongenitalem Nystagmus brachten eine sichere Grundlage für die Klassifizierung der zahlreichen Bewegungsformen. Es ergaben sich objektive Definitionen, die auf meßbaren Größen beruhen und nicht auf dem „klinischen Eindruck“. Die Genauigkeit der Ableitungen gewährte, zusammen mit Filmaufnahmen des Fundus, die während der Fixation eines Laser-Zielpunktes ausgeführt wurden, Einblicke in den Mechanismus des kongenitalen Nystagmus. Viele der Kurvenformen erklären sich aus dem Versuch, das Zielobjekt möglichst lange auf der Fovea zu belassen. Diese Strategie erfolgt im Interesse einer Verbesserung der Sehschärfe.
Article
Purpose: To compare results of retroequatorial recession of horizontal rectus muscles and Hertle-Dell'Osso tenotomy procedure in patients with infantile nystagmus with null in primary position. Methods: In this prospective study, 10 subjects ≥5 years of age with infantile nystagmus with null in primary position were randomly assigned to two groups: group 1 underwent a large retroequatorial recession of the four horizontal rectus muscles; group 2, simple tenotomy and resuturing (Hertle-Dell'Osso procedure) of the four muscles. Patients were evaluated using Snellen and logMAR visual acuity charts, contrast sensitivity testing, color vision testing, stereopsis testing (TNO), and electronystagmography (ENG) for nystagmus waveforms, frequency, amplitude, and intensity. Results: Group 1 patients showed a trend toward 1-line improvement in their visual acuity for distance on the logMAR and ETDRS charts (P = 0.32); there was no improvement in group 2 patients. Contrast sensitivity improved significantly in both groups (P = 0.03), as did stereopsis (P = 0.02 [group 1], P = 0.04 [group 2]). The amplitude and intensity of nystagmus showed a tendancy to decrease in both the groups in all gazes, although the frequency showed no change in either group. Intergroup variability on all the parameters was not statistically significant. Conclusions: Both retroequatorial recession of horizontal recti and the Hertle-Dell'Osso procedure showed a trend toward reducing ENG amplitude and improved contrast sensitivity and stereopsis in infantile nystagmus with null in primary position.
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• Aim: To observe the stereoacuity before and after operation of Parks shift of neutral zone in children with congenital idiopathic nystagmus. • Methods: Using synoptophore stereograms and near stereoacuity chart, the distance and near stereoacuity in primary gaze position and neutral zone of 12 children with congenital idiopathic nystagmus at pre-operation and 6 months after operation were examined. • Results: Nystagmus was disappeared or obviously relieved in the primary gaze position. Compensatory head position was eliminated in 7 cases after operation, and improved in 5 cases. Three cases established single binocular vision but no stereoscopic vision after operation. • Conclusion: Not only the compensatory head position, nystagmus and visual acuity are improved after operation of Parks shift of neutral zone, but the distance and near stereoscopic vision are established, visual quality is improved in cured compensatory head position cases.
Article
Objective: To investigate the effectiveness of rectus marginal myotomy for congenital nystagmus. Methods: Twenty-one cases with congenital nystagmus received modified parks operation. On the basis of Parks, rectus marginal myotomy is adopted instead of recession in Parks. Results: The zero zone of 15 cases(71.34%) was moved forward to the normal place, and the nystagmus in the normal place almost disappeared. 6 cases(28.57%) had a reduction of nystagmus, and their vision was remarkable improved. The compensatory head position was disappeared in 18 cases (85.71%) and attenuated in 3 cases and maintained stable in 15 cases during the 2-year follow-up. A satisfactory effectiveness was gotten in 18 cases after 2 years. Conclusion: Modified Parks surgery is a favorable alternation for congenital nystagmus.
Article
Purpose: To document prospectively the effect of four-muscle tenotomy surgery on visual acuity (VA) and nystagmus intensity and assess, by the use of a questionnaire, the experience of adult patients and the parents of children who have had the four-muscle tenotomy procedure for nystagmus in the absence of strabismus or an anomalous head position. The qualitative perceived benefits or lack thereof from the procedure were compared to the subjective effects on nystagmus intensity and VA. Methods: Fifteen patients diagnosed as having congenital/infantile or acquired nystagmus, including albinism or other visual sensory disorders without anomalous head positions or coexisting strabismus, were included in this study. The changes in preoperative and postoperative VA and nystagmus were evaluated based on clinical and perceptual measurements and video recordings. Results: All 15 patients had preoperative and postoperative ophthalmological examinations. One patient had a postoperative conjunctival cyst, which was successfully removed. Fourteen patients (93%) showed clinical VA improvement in at least one eye. Fourteen patients were video recorded preoperatively and postoperatively to analyze their nystagmus intensity; case 9 was not included. Postoperatively, 10 patients (71%) showed a decrease in nystagmus intensity. Thirteen patients (87%) perceived vision improvement and 11 patients (73%) perceived a decrease in nystagmus intensity. All patients experienced either clinically improved VA or a decrease in nystagmus intensity. Fourteen patients (93%) perceived either improved VA or a decrease in nystagmus intensity. The preoperative and postoperative changes in VA (P = .002) and nystagmus intensity (P = .043) were both statistically significant. Conclusions: The authors have shown that four-muscle tenotomy surgery for nystagmus can improve VA and decrease nystagmus intensity. The study yielded subjective patient satisfaction, modest objective improvement in VA, and no significant complications. [J Pediatr Ophthalmol Strabismus. 2016;53(1):16-21.].
Article
Large recession of the four horizontal rectus muscles has been shown at best to minimally improve visual acuity as measured with Snellen letters. However, many patients have reported a dramatic improvement in ability to recognize objects more quickly after large recession of the horizontal recti. We used a shutter device to measure the time it took six patients with nystagmus to recognize a projected Snellen “E” at the threshold of their vision before and after the four muscle recession surgery. Three control patients with nystagmus but not having had surgery were measured twice, two months apart. The mean preoperative time needed to correctly recognize the orientation of the tumbling “E” (recognition time) was .50 secs. (range 0.40 to 0.80) and the two month postoperative recognition time was 0.20 secs. (range 0.10 to 0.40). The mean initial recognition time for the control patients was 0.30 secs. and the mean repeat recognition time was 0.50 sees. These results indicate that the four muscle recession for nystagmus decreases the time necessary to recognize projected figures and therefore improves visual function measured in a non-traditional manner, and supports patient reports of improved vision which cannot be confirmed by improved snellen acuity.
Article
It has been suggested that contact lens wear improves the visual function of patients with visual loss from congenital nystagmus. In this study, four patients with congenital nystagmus had two evaluations separated by at least one week (one with spectacles, one with contact lenses) including visual acuity, contrast sensitivity, oscillopsia scale, quality of life questionnaire (NEI VFQ-25), and eye movement recording with an infrared tracking system. All patients subjectively preferred contact lenses to spectacles. Their contrast sensitivity and VFQ-25 scores were improved with contact lenses compared with spectacles alone. Several parameters of nystagmus showed no change in two patients, worsening in one patient and improvement in one patient. This suggests that much of the clinical improvement observed in our patients may result from a better optical correction of their refractive error with contact lenses than with spectacles, rather than from a true damping effect of the nystagmus by contact lenses.
Article
To evaluate and compare the effect of four horizontal rectus muscle Tenotomy And Replacement (TAR) alone and in combination with recessions for strabismus, on visual function and eye movement records in patients with INS without AHP, and to compare these results. This was a prospective interventional case series of 14 patients with INS with no AHP or eccentric null point. Patients underwent 4 horizontal eye muscle tenotomy and replacement (TAR) alone or 2 muscle TAR in combination with conventional bilateral horizontal muscle recession according to the presence and type of strabismus. Outcome measures included best corrected visual acuity and nystagmus intensity from eye movement recordings pre and post operatively. Data were compared between patients with strabismus and those without. Overall nystagmus amplitude and velocity was decreased 28.7% and 21.9% respectively for 4 muscle TAR and 2 muscle TAR with paired strabismus recessions. Visual outcome of combined procedure in patients with INS and strabismus was less comparing with 4 muscle tenotomy. All binocular deviations were surgically corrected and there was no undercorrection or complication. Visual acuity showed improvement in patients who had more impaired pre-operation vision. Most patients were satisfied with cosmetic outcomes. Tenotomy alone and combined with recession improves both visual function and eye movement records in INS. The procedures show better results in more visually impaired patients. We should consider patients preop VA and their visual potential as prognostic factors for their visual gain. Although visual outcomes are not advanced in all patients, nystagmus dampening effect and cosmetic outcome of these procedures can make them reconstructive options for patients with INS who will not achieve better vision.
Forty-three patients with congenital nystagmus who underwent surgery in the Ocular Motility Clinic at The Royal Victorian Eye and Ear Hospitar Melbourne, are analysed to assess the effect of different surgical approaches on the abnormal head posture and binocular visual performance. There were 38 patients with a horizontal head turn, and five with a vertical abnormal head posture. In those undergoing horizontal nystagmus surgery the different surgical procedures have been classified as (4 Anderson procedure, which involves large bilateral augmented recessions only; (ii) Kestenbaum and augmented Kestenbaum bilateral recess/resect surgery in which the recess:resect ratio is less than 1; and (iii) a modified Anderson-Kestenbaum procedure with the emphasis on large recessions. so that the bilateral recess/resect ratio is greater than 1. In this series the augmented recessions of the Anderson and Anderson-Kestenbaum procedures appeared to produce a more favourable result of improved binocular vision. The five patients with vertical abnormal head posture with nystagmus had various surgical procedures with very encouraging results, both in terms of reduction of the abnormal head posture and an even greater improvement of binocular vision than with the horizontal cases. The surgical techniques in these cases are presented and discussed.
Article
The design and efficacy of surgery for horizontal idiopathic nystagmus (HIN) with abnormal head posture and strabismus were investigated. Different surgical procedures were selected according to the angle of head turn in 44 cases of HIN with abnormal head posture and strabismus. For patients with a head turn of 15° or less, the Anderson procedure was used; the yoke muscles were recessed upon slow-phase. For patients with a head turn between 15° and 25°, the surgery was designed as a Kestenbaum 5-4-4-5 procedure. For patients with a head turn of 25° or more, the surgery was designed as a Parks 5-8-6-7 procedure. The surgery to correct the abnormal head posture was performed on the fixating eye while that to correct the deviation was then performed on the non-fixating eye at the same time. The amount of surgery of the horizontal rectus muscles on the non-fixating eye was sum of the angle of head turn and the degree of deviation, which was calculated as follows: recession/resection amount of medial and lateral rectis / 2×5 =angle of head turn ± degree of deviation. The results showed as follows: (1) Visual acuity: the visual acuity in the primary ocular position increased two lines or more in 35 patients, accounting for 79.55%. Nine patients had no or only one-line improvement, accounting for 20.45% of the entire study population; (2) The degree of deviation in the primary ocular position: 37 cases had a normal primary ocular position or the degree of deviation ≤ 8(δ) after surgery, accounting for 84.09%. Six patients had a residual degree of deviation of 8(δ)-15(δ), accounting for 13.64%. One patient had a residual degree of deviation >20(δ), accounting for 2.27% of the patients examined; (3) Abnormal head posture: 34 patients had a normal head posture or a head turn of less than 5°, accounting for 72.27%. Eight patients had a residual head turn of 5°-15°, accounting for 18.18%. Two patients had a head turn of 15°-25°, accounting for 4.55%. It was concluded that different surgical procedures based on the angle of head turn and the relationship between deviation and null zone can eliminate anomalous head posture, correct deviation, and improve vision acuity in the primary ocular position.
Article
BACKGROUND:: Recent advances in infantile nystagmus syndrome (INS) surgery have uncovered the therapeutic importance of proprioception. In this report, we test the hypothesis that the topical carbonic anhydrase inhibitor (CAI) brinzolamide (Azopt) has beneficial effects on measures of nystagmus foveation quality in a subject with INS. METHODS:: Eye movement data were taken, using a high-speed digital video recording system, before and after 3 days of the application of topical brinzolamide 3 times daily in each eye. Nystagmus waveforms were analyzed by applying the eXpanded Nystagmus Acuity Function (NAFX) at different gaze angles and determining the longest foveation domain (LFD) and compared to previously published data from the same subject after the use of a systemic CAI, contact lenses, and convergence and to other subjects before and after eye muscle surgery for INS. RESULTS:: Topical brinzolamide improved foveation by both a 51.9% increase in the peak value of the NAFX function (from 0.395 to 0.600) and a 50% broadening of the NAFX vs Gaze Angle curve (the LFD increased from 20° to 30°). The improvements in NAFX after topical brinzolamide were equivalent to systemic acetazolamide or eye muscle surgery and were intermediate between those of soft contact lenses or convergence. Topical brinzolamide and contact lenses had equivalent LFD improvements and were less effective than convergence. CONCLUSIONS:: In this subject with INS, topical brinzolamide resulted in improved-foveation INS waveforms over a broadened range of gaze angles. Its therapeutic effects were equivalent to systemic CAI. Although a prospective clinical trial is needed to prove efficacy or effectiveness in other subjects, an eyedrops-based therapy for INS may emerge as a viable addition to optical, surgical, behavioral, and systemic drug therapies.
Article
Recent advances in infantile nystagmus syndrome (INS) surgery have uncovered the therapeutic importance of proprioception. In this report, we test the hypothesis that the topical carbonic anhydrase inhibitor (CAI) brinzolamide (Azopt) has beneficial effects on measures of nystagmus foveation quality in a subject with INS. Eye movement data were taken, using a high-speed digital video recording system, before and after 3 days of the application of topical brinzolamide 3 times daily in each eye. Nystagmus waveforms were analyzed by applying the eXpanded Nystagmus Acuity Function (NAFX) at different gaze angles and determining the longest foveation domain (LFD) and compared to previously published data from the same subject after the use of a systemic CAI, contact lenses, and convergence and to other subjects before and after eye muscle surgery for INS. Topical brinzolamide improved foveation by both a 51.9% increase in the peak value of the NAFX function (from 0.395 to 0.600) and a 50% broadening of the NAFX vs Gaze Angle curve (the LFD increased from 20° to 30°). The improvements in NAFX after topical brinzolamide were equivalent to systemic acetazolamide or eye muscle surgery and were intermediate between those of soft contact lenses or convergence. Topical brinzolamide and contact lenses had equivalent LFD improvements and were less effective than convergence. In this subject with INS, topical brinzolamide resulted in improved-foveation INS waveforms over a broadened range of gaze angles. Its therapeutic effects were equivalent to systemic CAI. Although a prospective clinical trial is needed to prove efficacy or effectiveness in other subjects, an eyedrops-based therapy for INS may emerge as a viable addition to optical, surgical, behavioral, and systemic drug therapies.
Article
To report the effect of the abnormal head posture (AHP) correcting procedures on the visual acuity improvement in patients with infantile nystagmus syndrome (INS) and the visual acuity improvement outcomes in different AHP correcting surgeries in INS. This was a prospective, non-randomized, interventional study. Twenty-eight patients underwent the Anderson-Kestenbaum procedure or the modified Anderson procedure with or without tenotomy of at least one horizontal recti for correction of AHP. Best-corrected binocular null zone acuity and degree of AHP was recorded preoperatively and compared with those done 1 month postoperatively. The average null zone logarithm of the minimum angle of resolution acuity was 0.42 preoperatively, which improved significantly to 0.33 postoperatively (P = .002). The AHP ranged from 10° to 40° (mean: 20.89°), which improved significantly to a mean of 3.21° (P = .000). No significant difference (P = .65) was found in the visual acuity improvement among patients who underwent the Anderson-Kestenbaum procedure or the modified Anderson procedure with or without tenotomy. No significant difference in the visual acuity improvement was seen in patients who underwent tenotomy of at least one horizontal rectus muscle along with the modified Anderson procedure compared to those who underwent the modified Anderson procedure alone (P = .28). The procedures used mainly for correction of AHP in INS do yield significant improvement in the visual acuity. This improvement is seen in patients undergoing surgery for both horizontal and vertical AHP.
Article
The study of the clinical and electrophysiological effects of eye muscle surgery on patients with infantile nystagmus has broadened our knowledge of the disease and its interventions. Prospective, comparative, interventional case series. Twenty-four patients with a vertical head posture because of electrophysiologically diagnosed infantile nystagmus syndrome. The ages ranged from 2.5 to 38 years and follow up averaged 14.0 months. Thirteen patients with a chin-down posture had a bilateral superior rectus recession, inferior oblique myectomy and a horizontal rectus recession or tenotomy. Those 11 with a chin-up posture had a bilateral superior oblique tenectomy, inferior rectus recession and a horizontal rectus recession or tenotomy. Outcome measures included: demography, eye/systemic conditions and preoperative and postoperative; binocular, best optically corrected, null zone acuity, head posture, null zone foveation time and nystagmus waveform changes. Associated conditions were strabismus in 66%, ametropia in 96%, amblyopia in 46% and optic nerve, foveal dysplasia or albinism in 54%. Null zone acuity increased at least 0.1 logMAR in 20 patients (P < 0.05 group mean change). Patients had significant (P < 0.05) improvements in degrees of head posture, average foveation time in milliseconds and infantile nystagmus syndrome waveform improvements. This study illustrates a successful surgical approach to treatment and provides expectations of ocular motor and visual results after vertical head posture surgery because of an eccentric gaze null in patients with infantile nystagmus syndrome.
Article
To report a systematic approach to, and the visual and electrophysiological effect of, eye muscle surgery in 100 patients with infantile nyustagmus syndrome (INS). Prospective, interventional case cohort analysis of clinical and eye movement data in 100 patients with INS who had virgin extraocular eye muscles operated on for nystagmus with or without combinations of strabismus and an anomalous head posture. All patients were followed at least 9 months after surgery. Outcome measures, part of an IRB approved study, included binocular visual acuity, head position, strabismic deviation, and eye movement recordings, from which waveform types and an Automated Nystagmus Acuityn Function (ANAF) was calculated. Computerized parametric and non-parametric statistical analysis of data were performed using standard software on both individual and group data. There were 9 consistent surgical procedures used with the most common being that for a horizontal head posture alone (22%). Age at surgery averaged 14 years with 11 months followup. Sixty-eight percent had associated eye disease (optic nerve, retinal, amblyopia, cataracts). Group means in binocular acuity, strabismic deviation, head posture, abd ANAF measures from eye improved for all procedures. There were 12 (12%) reoperations without any serious surgical complications. Individual analysis revealed only age and head posture differences in outcome measures between the 9 procedures. Using this approach, surgery on the extraocular muscles in patients with INS results in improvements in multiple aspects of ocular motor and visual function.
Article
Anderson-Kestenbaum operations for congenital nystagmus with severe head turn have been employed for the past 25 years. They have been documented as being effective in correcting head turns associated with congenital nystagmus. We have studied a group of patients with congenital nystagmus and head turn, both preoperatively and postoperatively, by means of recordings of eye movements. We have documented the effect of surgery in shifting the null position, in broadening the null position, and in lowering the nystagmus intensity. In some cases, an improvement of the visual acuity has also occurred.
Article
The author reports the long-term (average 11 years) results of surgery to correct the face turn or tilt adopted to use the null zone associated with nystagmus. Of the 18 patients 16 had a face turn (7 with fusion and no strabismus, and 9 without fusion and strabismus) and 2 had a head tilt. Surgery was done after the age of 7 years (average 11 years), the same amount of surgery being done on all four horizontal rectus muscles in patients without strabismus to turn the eyes in the same direction as the face turn. Ten-millimetre recession/resection surgery produced the best correction of the face turn and the most gaze restriction. In patients with straight eyes before surgery strabismus was not produced or fusion or stereopsis lost. In patients with strabismus, surgery was modified on the nonfixing eye to correct the strabismus in addition to the face turn.
Article
Ten patients had large recession of four horizontal recti at one procedure for treatment of nystagmus. Six patients had congenital motor nystagmus, two had oculocutaneous albinism, and two had optic nerve hypoplasia. Anomalous head posture with null point was also present in five patients. The rectus muscles were placed at or behind the equator in all but one case. Three patients with both esotropia and nystagmus had the medial recti placed 1 mm behind the equator and the lateral recti or at 1 mm anterior to the equator. Visual acuity improved an average of 1 line at distance and/or near in 8 patients who cooperated for testing. Although nystagmus was not eliminated in any patient, its its amplitude decreased in eight of ten patients, and anomalous head posture improved in three of five patients. In all patients, near vision was better than distance vision both preoperatively and postoperatively. Ductions were diminished minimally after the large recession and there were no other complications from surgery.
Article
Retroequatorial recessions of the horizontal rectus muscles 10 to 12 mm behind their insertions reduced the amplitude of manifest congenital nystagmus in three patients. Modest improvement of visual acuity occurred in two patients. In a third patient with periodic alternating nystagmus, a compensatory head turn was eliminated by shifting the neutral zone of the nystagmus to the primary position of gaze. In spite of large recessions of the muscle insertions, none of the patients had a functionally significant postoperative limitation of ocular motility.
Article
We investigated the factors that determine the nature and extent of abnormal head postures in patients with congenital nystagmus. The head positions and eye movements of 16 patients were monitored while they adopted a variety of gaze positions. Five patients displayed a single head posture and four displayed multiple head postures. Six of the nine head postures matched the minimum intensity zone. The extent of the head posture was also found to be dictated by the velocity distribution of the slow phase, the nystagmus beat direction, and the neutral zone. Our results suggest that the surgical management of a head posture should not always be based only on the relocation of the minimum intensity zone to the primary gaze position.
Article
We describe six patients who, as teenagers or adults, developed florid nystagmus with consequent visual symptoms without any other manifestation of disease. In three patients, previous ophthalmologic examination had excluded nystagmus, and there was medically informed witness to its onset. The remainder may or may not have had a milder, unsuspected nystagmus before the development of symptoms. Ophthalmologic and neurologic investigations were negative, and follow-up of 2 to 15 years has been uneventful. Eye movement recordings showed the characteristics of the nystagmus to be indistinguishable from congenital nystagmus, which normally becomes manifest in early infancy. We conclude that a congenital-type nystagmus can emerge or enhance in later life without apparent provocation and is probably associated with a benign pathophysiology.
Article
The treatment possibilities for nystagmus have been expanded by the addition of the artificial divergence procedure. This paper presents a study on 26 nystagmus patients with and without anomalous head posture and good binocular function and with detailed pre- and postoperative electronystagmographic records. All patients had been treated by artificial divergence by means of a prism base out before the operation. Seventeen patients showed significant improvement after the artificial divergence procedure. In 3 patients this procedure had to be combined with the classic Kestenbaum procedure. In 6 patients, the effect of artificial divergence with prisms was not satisfactory; thus, the Kestenbaum procedure was necessary. This study proves the effectiveness of the artificial divergence procedure alone or in combination with other procedures for treatment of anomalous head posture and the improvement of visual acuity and binocular vision.
Article
Congenital nystagmus (CN) is a common disorder indicative of a primary disturbance of the ocular motor or visual sensory systems. The authors prospectively evaluated 81 patients with CN, structurally normal eyes, and minimal or no abnormalities of the optic nerve, macula, and retinal pigment epithelium (RPE). Seventy-four (91%) patients were found to have a disorder of the visual sensory system. Thirty-four patients had albinism, 37 had a congenital or early onset disorder of the retinal photoreceptors, and 3 had abnormalities of the optic nerve. The remaining seven (9%) patients had motor CN. Most patients presenting with CN have visual loss and should be evaluated for an underlying disorder of the visual sensory system.
Article
By analyzing the clinical data on the amount of surgery on the extraocular muscles and resulting angular shift of the null zone in 24 patients with congenital nystagmus, a linear dependence was found to exist between these two variables. Hence, the amount of surgery can be confidently established in advance of treatment in order to obtain the shift of the null zone. Many cases of partial surgical successes are discussed and explained a posteriori by a lack of a proper amount of surgical rotation.
Article
The paper describes results after surgical treatment of congenital nystagmus in 47 patients, aged 6--16 years; of them 34 patients had a jerk nystagmus with a neutral zone in the dextro- or levoversion and a forced position of the head, and 13 had a pendular nystagmus. In case of jerk nystagmus, bilateral recession--resection of horizontal muscles after Helveston was made, and in case of pendular nystagmus--a "faden-operation" after Cüppers. In most of patients (80%) the effect was positive: improvement of head position, decrease of nystagmus amplitude, increase of visual acuity. The best results were achieved in patients with jerk nystagmus. The authors recommend to use surgical treatment of congenital nystagmus in a more wider scale.
Article
Clinical peculiarities of nystagmus have been studied in 73 patients, aged from 5 to 15 years, possibilities of conservative and surgical treatment shown and results of the combined treatment analysed. A great attention was paid to a comprehensive study of this contingent of patients, and the method of registration and analysis of jerking movements of the eye in nystagmus is described. On deciding the question of surgical treatment for nystagmus it is necessary to consider the data of electrophysiologic investigations characterizing the functional state of the retina. As indications to surgical treatment were considered the presence of a selective position of the head, i.e. jerk nystagmus or its mixed form with predominance of a jerk component, when the amplitude of jerking movements of the eye becomes smaller and visual acuity increases. As a result of the operation, the forced position of the head could be corrected in 77% of cases, intensity of nystagmus reduced in 73.2%, and visual acuity elevated in 69.4%.