Effects of tenotomy on patients with infantile nystagmus syndrome: Foveation improvement over a broadened visual field

PURPOSE: To investigate the effects of four-muscle tenotomy on visual function and gaze angle in patients with infantile nystagmus syndrome (INS). METHODS: Eye movements of nine patients with infantile nystagmus were recorded using infrared reflection or high-speed digital video techniques. Experimental protocols were designed to record the patients' eye-movement waveforms, pre- and post-tenotomy, at different gaze angles. We used the eXpanded Nystagmus Acuity Function (NAFX) to measure tenotomy-induced changes in the nystagmus at primary position and various gaze angles. The longest foveation domains (LFD) were measured from fitted curves. Peak-to-peak nystagmus amplitudes and foveation-period durations were also measured. All measurements were made unmasked. RESULTS: All seven patients with narrow, high-NAFX, gaze-angle regions showed broadening of these regions of higher visual function. Three patients showed moderate NAFX improvement (13.9-32.6%) at primary position, five showed large improvement (39.9-162.4%), and one showed no NAFX change (due to his high pretenotomy NAFX). Primary position measured acuities improved in six patients. All patients had reductions in nystagmus amplitudes ranging from 14.6 to 37%. The duration of the foveation period increased in all nine patients (11.2-200%). The percentage improvements in both the NAFX and the LFD decreased with higher pretenotomy values. CONCLUSIONS: In addition to elevating primary position NAFX, tenotomy also broadens the high-NAFX regions. This broadening effect is more prominent in patients who had sharp pretenotomy NAFX peaks. Four-muscle tenotomy produces higher primary position NAFX increases in infantile nystagmus patients whose pretenotomy values are relatively low, with the improvement decreasing at higher pretenotomy values. The tenotomy procedure improves visual function beyond primary position acuity. This extends the utility of surgical therapy to several different classes of patients with INS for whom other procedures are contraindicated. The pretenotomy NAFX can now be used to predict both primary position acuity improvements and broadening of a patient's high-NAFX range of gaze angles.     

Horizontal rectus muscle tenotomy in children with infantile nystagmus syndrome: A pilot study

PURPOSE: We wished to determine the effectiveness of horizontal rectus tenotomy in changing the nystagmus of children with infantile nystagmus syndrome. DESIGN: This was a prospective, noncomparative, interventional case series in five children with varied sensory and oculographic subtypes of congenital nystagmus (including asymmetric (a)periodic alternating nystagmus) and no nystagmus treatment options. Simple tenotomy of all four horizontal recti with reattachment at the original insertion was accomplished. Search-coil and infrared eye movement recordings and clinical examinations were performed before and 1, 6, 26, and 52 weeks after surgery. Outcome measures included masked pre- and postoperative expanded nystagmus acuity function (NAFX), foveation time obtained directly from ocular motility recordings, and masked measures of visual acuity. RESULTS: At 1 year after tenotomy and under binocular conditions, two of the three patients for whom the NAFX could be measured had persistent, significant postoperative increases in the NAFX of their fixating eye. Average foveation times increased in these patients' fixating eyes. Measured binocular visual acuity increased in four patients; the remaining patient had retinal dystrophy. There were no adverse events due to surgery. CONCLUSIONS: In the two children who could fixate the targets for several seconds and for whom we could obtain accurate measurements of their infantile nystagmus, tenotomy resulted in significant improvements in nystagmus foveation measures. In those patients plus two others (four of five), measured visual function improved.     

先天性特发性眼球震颤手术治疗后视功能的恢复

背景先天性特发性眼球震颤的手术方式已日渐成熟,但其术后视功能的恢复仍然值得关注。目的探讨先天性特发性眼球震颤的手术治疗方法及其对视功能的影响。方法按照患者的头位扭转角大小和斜视度数的不同将60例先天性特发性眼球震颤患者分为4组,Ⅰ组：头位扭转角〈15°,水平斜视度≤15°,行本体感受器切除术;Ⅱ组：头位扭转角〈15°,水平斜视度〉15°,行本体感受器切除术联合斜视矫正术;Ⅲ组：头位扭转角≥15°,水平斜视度≤15°,行中间带移位术（部分同时施行本体感受器切除术）;Ⅳ组：患者头位扭转角≥15°,水平斜视度〉15°,行中间带移位联合斜视矫正术（部分同时施行本体感受器切除术）,采用自身对照法对患者手术前后单眼及双眼远近最佳矫正视力、头位扭转角、斜视度、眼球运动及立体视觉的变化进行比较。结果与术前相比,术后各组患者第一眼位单眼及双眼远视力均明显提高,差异均有统计学意义（单眼：t=6．00、8．94、11．76、16．41,P=0．00;双眼：t=4．81,P=0．0l;t=6．27、4．25、4．18,P：0．00）。术后Ⅰ组和Ⅱ组患者单眼及双眼近视力与术前比较差异无统计学意义（单眼：t=1．63,P=0．18;t=1．17,P=0．26;双眼：t=2．45,P=0．07;t=2．09,P=0．06）,而Ⅲ组和Ⅳ组患者术后单眼及双眼近视力均明显提高（单眼：t=2．91,P=0．01;t=5．32,P=0．00;双眼：t=3．36、4．30,P=0．00）。Ⅲ组和Ⅳ组中,术前有代偿头位的41例中,术后39例代偿头位消失,2例明显改善,头位扭转角手术前后比较差异有统计学意义（t=29．90、16．91,P=0．00）。术前26例合并斜视的患者中术后24例患者眼位正位,2例患者斜视欠矫,Ⅱ组、Ⅳ组斜视度明显降低,手术前后比较差异均有统计学意义（t=29．15、36．79,P=0．00）。所有患者术后眼球运动无受限。术前12岁以下的患儿共23例,立体视觉平均为256．52″±66．23″,术后1年其立体视觉平均为120．87″±45．31″,手术前后比较差异有统计学意义（t=12．06,P=0．00）。结论中间带移位术、本体感受器切除术及斜视矫正术可以改善先天性特发性眼球震颤患者的视功能、矫正头位及斜视。     

Distance and near visual acuity in infantile nystagmus.

PURPOSE: Infantile nystagmus (IN) has been reported to decrease with convergence. However, previous studies reported equivocal results regarding a corresponding improvement in acuity with near viewing. The aim of this study was to determine whether visual acuity improves with near viewing in patients with IN. METHODS: In the first experiment, visual acuities were measured using clinical test charts at standard test distances of 3 or 6 m and 40 cm and using S Charts at 3.75 m and 40 cm. In the second experiment, visual acuities were measured using a Bailey-Lovie chart at distance and a Lighthouse modified ETDRS near card held by each subject at his or her preferred working distance. S-chart acuities were obtained again at 3.75 m and 40 cm for comparison. Horizontal eye movements were recorded using infrared limbal reflection for 20 of the 34 subjects in the first experiment and for all 20 subjects in the second experiment. RESULTS: The S-chart acuities measured at distance and near were almost all within 0.1 logMAR (logarithm of the minimum angle of resolution) in experiments 1 and 2. Clinically measured acuity averaged nearly one line better at 40 cm than at distance in experiment 1, but the mean difference between near acuity using the ETDRS card and distance acuity using the Bailey-Lovie chart was less than one letter in experiment 2. No consistent relationship existed between the changes in visual acuity with viewing distance and the subject's eye movements. CONCLUSION: Despite a reduction of nystagmus at near distances in many patients with IN, the visual acuity at near does not improve significantly. These results imply that visual acuity in patients with IN is determined primarily by sensory limitations rather than by the moment-by-moment characteristics of these patients' eye movements.     

Effects of extraocular muscle surgery on 15 patients with oculo-cutaneous albinism (OCA) and infantile nystagmus syndrome (INS)

PURPOSE: The purpose of this report is to characterize the clinical and electrophysiological effects of extraocular muscle surgery in 15 patients with oculo-cutaneous albinism (OCA) and infantile nystagmus syndrome (INS). Our hypothesis is that surgery on the extraocular muscles of patients with OCA and INS changes their nystagmus and their visual function. DESIGN: Interventional, prospective, cohort, noncomparative case series. METHODS: All 15 patients had surgery on all four virgin horizontal recti; three for strabismus alone, three for nystagmus alone, five for an eccentric gaze null zone alone, and four for an eccentric gaze null zone plus strabismus. All patients have been followed for at least six months. All 15 patients had the subjective outcome measure of pre- and postoperative binocular best optically corrected acuity (BBOCA). Objective outcome measures included anomalous head posture (AHP) in nine patients, eye movement recording measures of expanded nystagmus acuity function (NAFX) in 10 patients, null zone position (NUZP) and null zone width (NUZW) in 10 patients, and foveation time (FOV) in nine patients. RESULTS: The results are summarized as follows; BBOCA increased 0.1 LogMar or greater in 14 of 15 patients. In those operated on for an AHP with or without associated strabismus the AHP improved significantly (P < .01 for all). The NAFX, NUZP, NUZW, and FOV measured from eye movement recordings showed persistent, significant increases in all patients (P < .01 for all). CONCLUSIONS: This report adds to the evidence that surgery on the extraocular muscles in patients with INS has independent neurologic and visual results.     

Eight eye muscle surgical treatment in a patient with acquired nystagmus and strabismus: a case report

The purpose of this paper is to outline the clinical benefits and electrophysiological changes after extraocular muscle surgery for acquired nystagmus and strabismus in an adult patient. a 41-year-old Caucasian female suffered from oscillopsia, bilateral cranial nerve IV palsies, and vertical nystagmus. Medical therapy was ineffective. She underwent bilateral, eight muscle surgical procedure which included: tenectomies of the superior oblique OU, myectomies of the inferior oblique OU, recessions of the medial rectus muscles OU (with OD on a post-operatively adjustable suture), and differential recessions of the superior rectus muscles OU. This provided marked improvement in her symptoms. These results suggest that surgery for acquired nystagmus can affect an improvement in the characteristics of the nystagmus that result in visual complaints. Combining "nystagmus surgery" plus strabismus surgery may be a viable option in some adult patients with acquired nystagmus who are unresponsive to medical therapy.     

Effect of infantile strabismus on visuomotor development in the squirrel monkey (Saimiri sciureus): Optokinetic nystagmus,motion VEP and spatial sweep VEP

PURPOSE. To determine whether squirrel monkeys made artificially strabismic in infancy had ocular fixation abnormalities, directional asymmetries of horizontal optokinetic nystagmus (OKN) and asymmetries of motion visually evoked potentials (MVEPs) similar to those of humans with infantile strabismus. METHODS. Esotropia was produced in a newborn squirrel monkey by surgical tenotomy of both lateral rectus muscles. The alignment and eye rotations of the monkey were examined longitudinally and VEP testing was performed at the age of one year. Visual acuity was measured using spatial frequency sweep VEPs (SSVEP) in response to grating stimulation. OKN was tested under conditions of monocular viewing using full-visual-field, vertically oriented, moving stripes. MVEPs in response to horizontal motion were recorded with the animal sedated to reduce the possibility of eye movement artifact. RESULTS. The artificially strabismic squirrel monkey displayed a constant, comitant esotropic strabismus accompanied by latent nystagmus. Monocular SSVEP acuity was subnormal in one eye, consistent with mild monocular strabismic amblyopia. The monkey demonstrated asymmetric OKN favoring nasally-directed stimulus motion when viewing with either eye. Monocular MVEPs were also characterized by a horizontal asymmetry with a directional bias inverted 180 degrees between the right and the left eyes. The eye movements and MVEP asymmetries were similar to those observed in strabismic macaque monkeys and humans with early-onset strabismus. Neither the OKN asymmetry nor the MVEP asymmetry was evident in a normal squirrel or normal macaque monkey. CONCLUSION. The artificially strabismic squirrel monkey is an appropriate eye movement and VEP model for the study of neural mechanisms in human infantile strabismus.     

Suppression of metabolic activity caused by infantile strabismus and strabismic amblyopia in striate visual cortex of macaque monkeys.

INTRODUCTION: Suppression is a major sensorial abnormality in humans and monkeys with infantile strabismus. We previously reported evidence of metabolic suppression in the visual cortex of strabismic macaques, using the mitochondrial enzyme cytochrome oxidase as an anatomic label. The purpose of this study was to further elucidate alterations in cortical metabolic activity, with or without amblyopia. MATERIALS AND METHODS: Six macaque monkeys were used in the experiments (four strabismic and two control). Three of the strabismic monkeys had naturally occurring, infantile strabismus (two esotropic, one exotropic). The fourth strabismic monkey had infantile microesotropia induced by alternating monocular occlusion in the first months of life. Ocular motor behaviors and visual acuity were tested after infancy in each animal, and development of stereopsis was recorded during infancy in one strabismic and one control monkey. Ocular dominance columns (ODCs) of the striate visual cortex (area V1) were labeled using cytochrome oxidase (CO) histochemistry alone, or CO in conjunction with an anterograde tracer ([H 3 ]proline or WGA-HRP) injected into one eye. RESULTS: Each of the strabismic monkeys showed inequalities of metabolic activity in ODCs of opposite ocularity, visible as rows of lighter CO staining, corresponding to ODCs of lower metabolic activity, alternating with rows of darker CO staining, corresponding to ODCs of higher metabolic activity. In monkeys who had infantile strabismus and unilateral amblyopia, lower metabolic activity was found in (suppressed) ODCs driven by the nondominant eye in each hemisphere. In monkeys who had infantile esotropia and alternating fixation (no amblyopia), metabolic activity was lower in ODCs driven by the ipsilateral eye in each hemisphere. The suppression included a monocular core zone at the center of ODCs and binocular border zones at the boundaries of ODCs. This suppression was not evident in the monocular lamina of the LGN, indicating an intracortical rather than subcortical mechanism. CONCLUSION: Suppression of metabolic activity in ODCs of V1 differs depending upon whether infantile strabismus is alternating or occurs in conjunction with unilateral amblyopia. Our findings reinforce the principle that unrepaired strabismus promotes abnormal competition in V1, observable as interocular suppression of ODCs.     

Rhino-orbital mucormycosis in a patient with acquired immunodeficiency syndrome (AIDS) and neutropenia.

PURPOSE: To present a case of rhino-orbital mucormycosis in a patient with AIDS and neutropenia managed without exenteration. METHODS: Case report. RESULTS: A 60-year-old African-American man with AIDS developed neutropenia that was probably secondary to antiretroviral therapy. He developed right rhino-orbital mucormycosis and was treated with right partial ethmoidectomy with debridement and liposomal amphotericin B. The infection was cured without need for orbital exenteration, although visual acuity in his right eye ultimately was no light perception. CONCLUSION: Rhino-orbital mucormycosis is uncommon in patients with AIDS. When rhino-orbital mucormycosis occurs, patients require a careful search for an underlying metabolic derangement such as neutropenia. Treatment should be aggressive, but these patients may not require orbital exenteration.     

Being "slow to see" is a dynamic visual function consequence of infantile nystagmus syndrome: model predictions and patient data identify stimulus timing as its cause

The objective of this study was to investigate the dynamic properties of infantile nystagmus syndrome (INS) that affect visual function; i.e., which factors influence latency of the initial reflexive saccade (Ls) and latency to target acquisition (Lt). We used our behavioral ocular motor system (OMS) model to simulate saccadic responses (in the presence of INS) to target jumps at different times within a single INS cycle and at random times during multiple cycles. We then studied the responses of 4 INS subjects with different waveforms to test the model's predictions. Infrared reflection was used for 1 INS subject, high-speed digital video for 3. We recorded and analyzed human responses to large and small target-step stimuli. We evaluated the following factors: stimulus time within the cycle (Tc), normalized Tc (Tc%), initial orbital position (Po), saccade amplitude, initial retinal error (e(i)), and final retinal error (e(f)). The ocular motor simulations were performed in MATLAB Simulink environment and the analysis was performed in MATLAB environment using OMLAB software. Both the OMS model and OMtools software are available from http://http:www.omlab.org. Our data analysis showed that for each subject, Ls was a fixed value that is typically higher than the normal saccadic latency. Although saccadic latency appears somewhat lengthened in INS, the amount is insufficient to cause the "slow-to-see" impression. For Lt, Tc% was the most influential factor for each waveform type. The main refixation strategies employed by INS subjects made use of slow and fast phases and catch-up saccades, or combinations of them. These strategies helped the subjects to foveate effectively after target movement, sometimes at the cost of increased target acquisition time. Foveating or braking saccades intrinsic to the nystagmus waveforms seemed to disrupt the OMS' ability to accurately calculate reflexive saccades' amplitude and refoveate. Our OMS model simulations demonstrated this emergent behavior and predicted the lengthy target acquisition times found in the patient data.     

获得性免疫缺陷综合征并发巨细胞病毒视网膜炎患者抗病毒治疗前后视功能的变化

目的　探讨获得性免疫缺陷综合征并发巨细胞病毒（ｃｙｔｏｍｅｇａｌｏｖｉｒｕｓ,ＣＭＶ）视网膜炎的患者在抗病毒治疗前后视功能的变化。方法　对１１例感染人类免疫缺陷病毒并且第１次发生ＣＭＶ视网膜病变的患者,给予膦甲酸钠和更昔洛韦治疗。治疗前、治疗后１个月、３个月,通过多焦视网膜电图对每例患者的视功能进行评估,以未感染人类免疫缺陷病毒的正常人眼作为正常对照组,观察患眼视功能的改善情况。结果　ＣＭＶ视网膜炎患者ｍｆＥＲＧ一阶反应中心区域Ｎ１-Ｐ１的振幅密度,治疗前为（３６．９８±１７．９３）ｎＶ?ｄｅｇ－２,治疗１个月后为（４１．３３±１６．７８）ｎＶ?ｄｅｇ－２,治疗３个月后为（３６．１２±１５．４６）ｎＶ?ｄｅｇ－２,正常对照组为（７６．９９±１１．２７）ｎＶ?ｄｅｇ－２。患眼发病时与正常对照组相比较,１～４环区域ｍｆＥＲＧ的一阶反应Ｎ１-Ｐ１的振幅密度均显著降低,差异有统计学意义（均为Ｐ＜０．０５）。患眼在治疗后１个月和３个月,１～６环区域ｍｆＥＲＧ的一阶反应Ｎ１波和Ｐ１波的潜时,以及Ｎ１-Ｐ１的振幅密度与治疗前相比均没有明显改变,差异均无统计学意义（均为Ｐ＞０．０５）。结论　ＣＭＶ视网膜炎的患者在经过积极地抗病毒治疗后,视力虽然能够得到不同程度上的恢复,但视网膜外层仍然受到不可逆的损伤,视网膜的功能显著降低。     

The effect of bilateral horizontal rectus recession on visual acuity, ocular deviation or head posture in patients with nystagmus.

PURPOSE: This work was undertaken to evaluate the effect of bilateral horizontal rectus recession on visual acuity, ocular deviation and head posture in patients with nystagmus. METHODS: Twenty patients underwent recession of 4 horizontal rectus muscles to dampen the nystagmus. At least 2 muscles were recessed posterior to the equator. RESULTS: Monocular and binocular visual acuity improved from 1 to 3 Snellen lines after the procedure in 13 patients (76.5%). Visual changes in log MAR notations were statistically significant with Wilcoxon analysis in each and both eyes. Preoperative binocular visual acuity was 0.73 +/- 0.26 log MAR that reached to 0.62 +/- 0.32 log MAR after surgery (P = 0.02). The greatest improvement was observed in patients with congenital motor nystagmus. Ten patients had horizontal strabismus in addition to nystagmus before the surgery. One-millimeter additional recession of both medial rectus muscles caused an average reduction of 6 PD in esotropia. Corresponding figures for similar additional recessions of the lateral rectus muscles was 11 PD for correction of exotropia. Abnormal head posture decreased in all the cases and improved completely in most of them. CONCLUSIONS: Large horizontal rectus recession can improve visual acuity and decrease nystagmus in sensory and motor types. By revision in surgical planning, strabismus and abnormal head posture can also be corrected.     

Relationships among visual acuity demands, convergence, and nystagmus in patients with manifest/latent nystagmus.

BACKGROUND: We investigated the role convergence plays in nystagmus dampening, in particular, relationships among visual acuity demands, convergence, and nystagmus. Previously we showed that subjects with idiopathic infantile nystagmus exhibit a range of responses to acuity targets, one of which is nystagmus blockage syndrome. We report herein eye movement responses to acuity targets of patients with manifest/latent nystagmus. METHODS: Fourteen patients, 11 with latent or manifest latent nystagmus and 3 with combined manifest latent with infantile nystagmus, were asked to indicate the direction of the gap in Landolt C optotypes while their eye movements were recorded. RESULTS: The tested patients exhibited various responses to acuity demands: (1) dampening of nystagmus with convergence (i.e., nystagmus blockage syndrome) (5/14 patients), (2) changes in vergence without nystagmus dampening (2 patients), (3) decrease of nystagmus without convergence (2 patients), and (4) little change in nystagmus or vergence (5 patients). In nystagmus blockage syndrome the amount of convergence increased with acuity demands in two of five patients and the convergence duration in four of five patients; nystagmus dampening increased with acuity demands in one of five patients and the blockage duration in four of five patients. CONCLUSIONS: Many, but not all, patients with manifest/latent nystagmus, similar to those with infantile nystagmus, used convergence to dampen their nystagmus. The convergence response tended to increase with acuity demands, but the amount of dampening was idiosyncratic and not predictably related to the measured convergence across patients.     

间歇性外斜视患儿术后视功能及多焦视觉诱发电位的变化

目的:探讨间歇性外斜视术对斜视患儿视功能及多焦视觉诱发电位的影响。方法:选取2014-01/2017-12期间就诊的91例间歇性外斜视患儿为研究对象,所有患儿均手术治疗。观察患儿手术前后视功能变化情况,检测其手术前后多焦视觉诱发电位水平。结果:术后1wk总有效率为88%,术后6mo总有效率为86%;术前患儿平均斜视度为-38.12△,术后为-5.8△。术后6mo同时视、融合、远立体视的患儿例数较术前显著增加(P<0.01);术后6mo患儿正位率为68%;术前三级视功能都存在或只存在其一二者术后绝大多数为正位,相比其丧失者术后正位率明显较高(P<0.05)。自术前至术后6mo患儿第四环、第六环的特征峰振幅反应密度与鼻侧、颞侧视网膜潜伏期水平均显著升高,下方视网膜潜伏期水平显著下降(P<0.05)。结论:间歇性外斜视术可有效提高患儿视功能,促进患儿眼位的恢复,且术后患儿多焦视觉诱发电位水平也得到一定改善,临床效果突出。     

Complex visual hallucinations in a patient with bilateral visual impairment (Charles Bonnet syndrome)

PURPOSE/METHODS: To report the occurrence of complex visual hallucinations in a 69-year-old female with bilateral age-related macular degeneration and unilateral cataract. Her orientation and cognition were normal and she showed no evidence of psychiatric symptoms. RESULTS/CONCLUSIONS: A case of a patient who presented with visual symptoms characteristic of the Charles Bonnet syndrome is reported. Various conditions associated with visual hallucinations must be kept in mind by the ophthalmologist (Arch Soc Esp Oftalmol 2003; 78: 327-330).