Treatment Of Strabismus Research Articles

Effects of botulinum a toxin injection on the extraocular muscle fiber layers: Comparison between subtenon injection and intramuscular injection

To compare the morphological changes following injection of botulinum A toxin to the extraocular muscle fiber layers with those following injection to the subtenon intramuscular system. Twelve New Zealand white rabbits were divided into two groups. In the first group (six rabbits), four received injections of 10 units of botulinum A toxin into the subtenon space of the superior rectus muscle OD, and the same dose of botulinum A toxin was injected directly into the superior rectus muscle OS. The other two rabbits in the first group were labeled as control animals; 0.1 ml of normal saline was injected into the subtenon space OD, and direct intramuscular injection was performed on the opposite eye. The animals in the first group were killed after 4 weeks to measure the average diameter of the muscle fibers in both the orbital and global layer. In animals of the second group (six rabbits), the same procedures were performed and the animals were killed 12 weeks after treatment. The average diameter of muscle fibers in both the orbital layer and global layer was markedly reduced in all of the botulinum A toxin-injected groups at 4 weeks after treatment compared with the controls. There was no difference in the average diameter of the muscle fibers between the orbital layer of the subtenon-injected group and that of the intramuscular-injected group at 4 weeks after treatment, but the average diameter of the muscle fibers in the global layer was significantly reduced in the intramuscular-injected group compared with the subtenon-injected group at 4 weeks after treatment. At 12 weeks following treatment, there was no difference in the average diameter between the botulinum A toxin-injected group and the control group regardless of where the toxin was injected. Subtenon injection of botulinum A toxin induced similar morphological changes as direct intramuscular injection in the extraocular muscle fiber layers. These results suggest the possibility of clinical applications of subtenon botulinum A toxin injection for the treatment of strabismus.

Treatment on 84 cases of children comitant strabismus

目的 评价儿童共同性外斜视的手术治疗效果.方法 对84例年龄在4～12岁共同性外斜视进行手术治疗,并进行4～12个月随访观察.结果 术后74例眼位正位,占手术总数88.10%;25例恢复了双眼单视功能,占术前无双眼单视功能者的50.00%,30例恢复立体视功能,占术前无立体视功能者的53.57%.结论 手术在纠正儿童共同性外斜视眼的同时,能够有效地恢复部分患者的双眼单视功能和立体视功能。

129: Surgical secrets

The acquisition and enhancement of surgical skills in the treatment of strabismus is a lifelong journey. During the course of a career, each surgeon develops a range of surgical secrets to facilitate care. These secret personal techniques may make a difficult step easier, make surgery more efficient, make surgery safer, or may enhance outcomes. The purpose of this workshop is to reveal an assortment of these surgical secrets that both the novice and expert surgeon will find valuable. With a heavy emphasis on video presentations, 15 individual presenters, with varying levels of surgical experience, will be allowed a maximum of 5 minutes to present her or his favorite surgical tip(s). This workshop promises to be fast-paced, entertaining, and very informative. Unfinished presentations that are still in progress will be terminated at exactly 5 minutes to assure that this workshop remains both dynamic and on schedule.

Results of Surgical Treatment for Paralytic Strabismus

Purpose: To study the correction effects of standard recession and resection in paralytic strabismus excluding superior oblique palsy. Methods: Eighteen cases of paralytic strabismus treated by standard recession and resection from March 2005 to October 2007 were retrospectively analyzed. Results: The average angles of deviation before surgery and after surgery were 55 prism diopters (PD) and 12PD, respectively. Adjustable suturing was performed in 12 cases. The diplopia was improved in 14 out of 18 cases (77%) after surgery. Three cases of the -4 grade paralyzed group had a large residual deviation after surgery. The success rate was 78% (14/18) when success was defined as a residual deviation of less than 15PD. Severe ocular motility limitation (-4 grade) group was less affected than other groups. In the below -3 grade paralyzed groups, patients resolved diplopia in the primary eye position, and did not complain of diplopia by incomitance in the secondary eye position. Conclusions: Standard recession and resection may actively be attempted in below -3 grade paralytic strabismus patients to resolve diplopia in the primary eye position.

A critical evaluation of the evidence supporting the practice of behavioural vision therapy

In 2000, the UK's College of Optometrists commissioned a report to critically evaluate the theory and practice of behavioural optometry. The report which followed Jennings (2000; Behavioural optometry--a critical review. Optom. Pract. 1: 67) concluded that there was a lack of controlled clinical trials to support behavioural management strategies. The purpose of this report was to evaluate the evidence in support of behavioural approaches as it stands in 2008. The available evidence was reviewed under 10 headings, selected because they represent patient groups/conditions that behavioural optometrists are treating, or because they represent approaches to treatment that have been advocated in the behavioural literature. The headings selected were: (1) vision therapy for accommodation/vergence disorders; (2) the underachieving child; (3) prisms for near binocular disorders and for producing postural change; (4) near point stress and low-plus prescriptions; (5) use of low-plus lenses at near to slow the progression of myopia; (6) therapy to reduce myopia; (7) behavioural approaches to the treatment of strabismus and amblyopia; (8) training central and peripheral awareness and syntonics; (9) sports vision therapy; (10) neurological disorders and neuro-rehabilitation after trauma/stroke. There is a continued paucity of controlled trials in the literature to support behavioural optometry approaches. Although there are areas where the available evidence is consistent with claims made by behavioural optometrists (most notably in relation to the treatment of convergence insufficiency, the use of yoked prisms in neurological patients, and in vision rehabilitation after brain disease/injury), a large majority of behavioural management approaches are not evidence-based, and thus cannot be advocated.

Botulinum Neurotoxin as a Therapeutic Modality in Orthopaedic Surgery: More Than Twenty Years of Experience

Seyler, Thorsten M. MD1; Smith, Beth P. PhD1; Marker, David R. BS2; Ma, Jianjun MD, PhD1; Shen, Jian MD, PhD1; Smith, Tom L. PhD1; Mont, Michael A. MD2; Kolaski, Kat MD1; Koman, L. Andrew MD1 Author Information

Long-term management of strabismus with multiple repeated injections of botulinum toxin

In the healthcare system in the United Kingdom, a number of patients may be offered botulinum toxin as an alternative to surgery in the treatment of their strabismus. We report on our experience of treating those who have received 25 or more injections. A retrospective review of the botulinum toxin clinic database was used to identify patients who underwent 25 or more injections between November 1982 and January 2006. All patients with strabismus who met this criterion were included. A statistical analysis was performed in which we compared aspects of this group with those who had received 24 or fewer injections. Fifty-seven patients (0.90%) fulfilled our criteria. There were 37 women and 20 men, with a mean age at first injection of 39 years (range, 15 to 80 years). The number of injections per patient ranged from 25 to 68 (mean, 34). The duration of treatment was between 3 and 22 years. The time interval between injections tended to increase in most patients and the angle tended to reduce. There was no statistical difference between the age at first injection, sex, site injected, diagnosis, and complication rate between the long-term group and the group that received 24 or fewer injections. The long-term group, however, had undergone more previous operations (p < or = 0.001) and had a lower degree of binocularity (p </= 0.001). The treatment of strabismus with botulinum toxin on a long-term basis is practicable and valuable in patients with poor binocular potential, complicated strabismus, or multiple previous strabismus operations. A trend toward fewer injections with time was observed, and no significant adverse effects were observed with long-term treatment.

Surgical treatment of myopic strabismus fixus: a graded approach

Surgical treatment of myopic strabismus fixus is challenging. Options for its correction range from conventional combined recession-resection surgery to innovative surgical procedures aiming to correct the deviated muscle paths. In this report we review our experience and compare the results of various surgical options for treatment of strabismus fixus. We report the surgical outcomes of nine adults with acquired strabismus fixus due to myopia with a follow-up of 1 year. Patients were enrolled between May 2003 and April 2007 in this retrospective study. The surgical procedure was determined depending on the angle of deviation and extent of motility impairment. A new transposition technique was performed in one patient who had an extreme variant of strabismus fixus. Combined recession-resection surgery was performed in four patients with resulting small-angle esotropia. In patients with both esotropia and hypotropia due to muscle alignment, we performed an additional upward displacement of both horizontal recti muscles combined with a myopexy of the lateral rectus muscle. The results were satisfying; in particular in one patient who had a transposition procedure a significant improvement was achieved. For treatment of myopic strabismus fixus, a graded approach seems advisable. Combined recession-resection surgery yields good results for smaller deviations with mildly impaired motility, additional fixation techniques need to be applied once the horizontal muscle paths are deviated, and in extreme cases, a transposition procedure is required.

Rectus Muscle Posterior Tenon Fixation as an Inactivation Procedure

To report a surgical technique and the results of rectus muscle posterior Tenon fixation as an inactivation procedure for treatment of Duane syndrome, restrictive strabismus, and long-standing paralytic strabismus, which conventionally require large rectus muscle recession. Prospective, interventional case series. Three eyes in three Duane syndrome patients, one eye in one myopic strabismus fixus patient, one eye in one complete third nerve palsy patient, and one eye in complete sixth nerve palsy patient underwent rectus muscle inactivation by disinsertion and posterior Tenon fixation of its insertion. The main outcome measures were the postoperative eye position in all patients, the presence of upshoot or downshoot on adduction, and, in Duane syndrome patients only, the height of the palpebral fissure. In Duane syndrome patients, the upshoot and the downshoot were improved markedly, and the height of the palpebral fissure was increased on adduction after the operation as compared with before the operation; the other patients had improved ocular alignment after surgery. We believe that rectus muscle inactivation by fixation of its insertion to posterior Tenon is an effective and less invasive technique for achieving profound weakening of a rectus muscle compared with periosteal fixation of the rectus muscle.

Nationwide study of hospitalization and surgical treatment for childhood strabismus in Italy between 1999 and 2004

Surgery for strabismus is in decline in countries like the United Kingdom. The aim of the present study was to determine whether this trend is also present in Italy and, also, to ascertain the number of squint operations performed in a six-year period. A retrospective review of all discharge summaries and procedures performed (diagnostic and therapeutic) for strabismus in Italian children aged 0-14 years old in the period 1999-2004 was undertaken. The total number of surgical procedures was 21,204. The number (per 10,000) was 4.24 in 1999, 4.33 in 2000, 4.31 in 2001, 4.25 in 2002, 4.23 in 2003, and 4.05 in 2004. The figure for 2004 was reduced by 4.48% with respect to 1999 and by 6.46% with respect to 2000. Temporal analysis revealed that the total number of single-muscle procedures remained stable for the first two years and then decreased in 2001 and 2002, and, above all, in 2003 and 2004. No significant change was noted in the number of procedures involving two or more muscles. It is also noteworthy that very few operations for strabismus were performed on children less than one year of age. The trend revealed by our data cannot be compared to the overall reduction in strabismus surgery that has been observed in England and Ontario, but there was a moderate decrease in the frequency of single-muscle surgical procedures among Italian children aged 0-14 years old in 2003 and 2004. Further investigation is needed to determine how this trend has evolved since 2004.

General Principles in the Surgical Treatment of Paralytic Strabismus

The surgical approach necessary to achieve the largest field of usable single binocular vision in patients with paralytic strabismus is one that has a greater effect in some directions of gaze than in others. Developing the appropriate “incomitant” strabismus surgery can be achieved by improving the ocular rotation of the involved eye(s), creating a matching rotation defect in the “normal” eye, and anticipating that surgery may create a new/different deviation (not present before the surgery) that can be used to surgeons' advantage. The severity of the limitation in ocular rotation will determine the amount and type of strengthening or weakening that will be necessary to the paralytic muscle and its yoke muscle.

Myogenic Growth Factors Can Decrease Extraocular Muscle Force Generation: A Potential Biological Approach to the Treatment of Strabismus

Future pharmacologic treatment of strabismus may be optimized if drugs that are less potentially toxic to patients can be developed. Prior studies have shown that direct injection of extraocular muscles (EOMs) with insulin growth factor or fibroblast growth factor results in significant increases in the generation of EOM force. The purpose of this study was to examine the morphometric and physiological effects of direct EOM injection with the growth factors BMP4, TGFbeta1, Shh, and Wnt3A. One superior rectus muscle of normal adult rabbits was injected with BMP4, TGFbeta1, Shh, or Wnt3A. The contralateral muscle was injected with an equal volume of saline to serve as a control. After 1 week, the animals were euthanatized, and both superior rectus muscles were removed and assayed physiologically. The muscles were stimulated at increasing frequencies to determine force generation. A separate group of treated and control superior rectus muscles were examined histologically for alterations in total muscle cross-sectional area and myosin heavy chain isoform (MyHC) composition. One week after a single injection of BMP4, TGFbeta1, Shh, or Wnt3A, all treated muscles showed significant decreases in generation of force compared with control muscles. BMP4, TGFbeta1, Shh, and Wnt3A significantly decreased the mean myofiber cross-sectional area of fast MyHC-positive myofibers. BMP4 resulted in a conversion of fast-to-slow myofibers and a significant decrease in the percentage of developmental and neonatal MyHC-positive myofibers. Alterations in mean cross-sectional area and proportion of MyHCs were seen after injection with TGFbeta1, Shh, and Wnt3A. TGFbeta1 and BMP4 injections resulted in increased Pax7-positive satellite cells, whereas BMP4, TGFbeta1, and Wnt3A resulted in a decrease in MyoD-positive satellite cells. These results suggest that, rather than using toxins or immunotoxins, a more biological approach to decrease muscle strength is possible and demonstrate the potential utility of myogenic signaling factors for decreasing EOM strength. Ongoing drug-delivery studies will elucidate means of extending treatment effect to make such agents clinically useful.

The Functional Benefits of Adult Strabismus Treatment

Treatment for adult strabismus patients (those above the age of visual maturity, or age 8–9 years) yields many functional benefits. Nonsurgical therapy can address symptoms of diplopia, pain, and asthenopia, as well as torticollis. These modalities include “tincture of time,” eye exercises, lenses, prisms, occlusion, and pharmacologic agents.Strabismus surgery in adults yields many measurable gains, and these can be categorized under: 1) relief of symptoms; 2) regaining of sensory and motor fusion; 3) normalizing the static field of binocular vision; 4) normalizing the field of binocular single vision; 5) improving psychosocial parameters; 6) generating positive cost-benefit analyses. These improvements are possible even when one eye is amblyopic. The cumulative evidence from all of these aspects confirms that adult strabismus surgery is “restorative” or “reconstructive” therapy, and should not be labeled as “cosmetic.”

Botulinum toxin A for the treatment of chronic anal fissure

Since its introduction for the treatment of strabismus, botulinum toxin (BoNT) has been increasingly used in the treatment of several disorders with excessive or inappropriate muscle contractions. The therapeutic effects of BoNT occur through the temporary chemodenervation caused by the injection into the local target muscle or skin. Modulation of muscle relaxation may be achieved by varying the dose of BoNT solution injected; most adverse effects are transient. Indeed, botulinum neurotoxin has been used to selectively weaken the internal anal sphincter as a treatment for chronic anal fissure in several randomized, controlled trials and open-label studies. The use of botulinum neurotoxin seems to be an effective and safe approach for the treatment of chronic anal fissure, particularly in patients at high risk for incontinence.

This issue of Acta

This issue of Acta focuses on paediatric ophthalmology and the retina. The cover figure shows a child with unilateral cataract and strabismus and comes from the review article by Charlotta Zetterström and Maria Kugelberg, of Oslo and Stockholm, respectively. The editorial is written by Michael O’Keefe in Dublin and discusses intraocular lenses in children. This relates directly to the review on paediatric cataract surgery by Zetterström and Kugelberg. The other review paper published in this issue, by Gunnar Lennerstrand, of Stockholm, discusses strabismus and eye muscle function. Together, the two articles present a comprehensive review of these two important subjects in paediatric ophthalmology. Continuing with the subject of paediatric ophthalmology, Fahnehjelm et al., based in Stockholm, examined the ocular effects of stem cell transplantation in the context of paediatric cancer treatment. The visual function of the children in their sample was generally good, but the majority developed cataracts to some degree. Hoerantner et al., writing from Austria, compared two surgical techniques for treatment of strabismus that requires ocular motor torque reduction. An investigation carried out in Brazil by Medina et al. found that dry eye in children is frequently associated with systemic disease. Longterm treatment is necessary to preserve ocular health and vision. Based in Stockholm and China, Zhang et al. found that cataract development following ultraviolet irradiation may depend on the type of anaesthetic used in the experimental rats. Coma et al., writing from the USA and Spain, found an association between tumour necrosis factor α and ocular cicatricial pemphigoid and suggest that a causal relationship may be present. Lundström et al., in Umeå and Shanghai, investigated the oscillatory potentials in the human electroretinogram. They observed that the oscillatory response may be activated by a single flash after dark adaptation, that adaptation to mesoptic background light does not change the response and that the response reflects a neuronal adaptation to a change in light level. German authors Meyer et al. present a thorough investigation of the visual and haemodynamic effects of racemose haemangioma. UK-based Higgings and associates, of Liverpool, revisited the importance of controlling risk factors for diabetic retinopathy and found that, despite well established scientific knowledge, many diabetes patients have poorly controlled blood pressure and glucose levels. Wimpissinger and Binder, reporting from Vienna, found sclerotomy-related retinal detachments in 11 of 244 pars plana vitrectomies and suggest that this complication may be prevented with meticulous cleaning of the vitreous base and postoperative examination of the entry sites. Kotliar and associates, based in Germany and Russia, examine the physics of intravitreal injections and the intraocular pressure peak that immediately follows such an injection. Korean researchers Oh et al. found that triamcinolone inhibits the proliferation of fibroblasts and retinal pigment epithelial cells in vitro. Akkoyun et al., writing from Ankara, report their findings that triamcinolone suppresses the proliferation endothelial cells in vivo in a mouse model of retinopathy of prematurity. Paris-based Lecleire-Collet and associates present a case where diabetic cystoid macular oedema treated with triamcinolone injection ended with a full-thickness macular hole. Brazilian authors Cella and Ávila evaluated branch retinal artery occlusion with the help of optical coherence tomography. I hope that all readers find material that is useful, interesting and stimulating in this issue of Acta and that we may use this issue of the journal to refresh our knowledge of paediatric ophthalmology.

Estrabismo y cataratas congénitas

To study the prevalence, characteristics, indications for and results of strabismus treatment secondary to congenital cataracts. This was a retrospective study of 21 cases from 29 with congenital cataracts with strabismus (unilateral in 11 and bilateral in 10 cases). In 20 patients surgery on the cataracts was performed, with an intraocular lens inserted in 15 patients. Botulinum toxin and/or strabismus surgery were deemed to be indicated when the deviation was stable after rehabilitation therapy. A good motor end result was considered when the final deviation was < or =5 degrees, and a good sensorial result was when there was no suppression in the Worth test even without stereopsis in the TNO test. The strabismus prevalence was 72.4%. Strabismus was present before cataract surgery was performed in 12 cases, 8 with esotropia (ET) and 4 with exotropia (XT). Strabismus which appeared after cataract surgery was classified as 13 ET, 5 XT, 1 ET with vertical anisotropia in <<V>>, and 2 XT with dissociated vertical deviation (DVD). The strabismus angle was variable in 6 patients and was not treated. The other 6 cases required strabismus treatment. Botulinum toxin was injected as the only treatment in 1 patient, strabismus surgery was performed in 4, and strabismus surgery and botulinum toxin were used in another case. The average age at the time of treatment was 5.2 years. The motor result was good in 5 cases (83.3%) and the sensorial result good in two (33.3%). Strabismus secondary to congenital cataracts occurred in a significant number of patients and increased after cataract extraction. Esotropia occurred twice as often as exotropia. Strabismus surgery was not required in most of the cases. The motor results were better than sensorial results.

Strabismus associated with thyroid eye disease

We discuss the evaluation and treatment of strabismus related to thyroid eye disease with special attention to the literature published in 2006. The etiology of thyroid eye disease is complex, although a recent review article evaluated the causative relationship between smoking and thyroid eye disease. The treatment of thyroid eye disease is also complex and involves a multidisciplinary approach including endocrinology and ophthalmology. Several recent articles have evaluated the role of medications in the treatment of thyroid eye disease. We discuss the current surgical strategies for the treatment of strabismus related to thyroid eye disease, including the use of adjustable suture techniques. New techniques in nonadjustable surgery are also examined. Strabismus related to thyroid eye disease presents many challenges to the ophthalmologist. Successful treatment of strabismus is rewarding however, and has a significant impact on improving a patient's quality of life.

Neuromuscular junctions of human extraocular muscles: looking for new tools for medical treatment of strabismus

Neuromuscular junctions of human extraocular muscles: looking for new tools for medical treatment of strabismus

Myofiber Length and Three-Dimensional Localization of NMJs in Normal and Botulinum Toxin–Treated Adult Extraocular Muscles

The density and three-dimensional localization of neuromuscular junctions (NMJs) of normal and botulinum toxin-treated normal adult rabbit and monkey extraocular muscles (EOMs) were analyzed. To demonstrate average myofiber length, randomly selected individual myofibers were reconstructed and compared with total muscle length. Normal adult rabbit and monkey EOM and normal adult rabbit tibialis anterior were dissected in their entirety, frozen, sectioned longitudinally, and immunostained for NMJ localization. In addition, adult rabbit EOMs were injected with 5 U botulinum toxin, and NMJ density was determined after 2 weeks. NMJ locations for the three groups of EOM were reconstructed, and density of NMJ was determined. Individual myofibers were reconstructed from the orbital and global layers to determine mean fiber length. NMJs were dispersed throughout the entire length of all EOMs examined from adult rabbits and monkeys and were visualized by alpha-bungarotoxin staining and three-dimensional reconstruction of serial sections. In leg muscle, two relatively tight bands of NMJs were seen. Botulinum toxin significantly increased total NMJ density. Mean fiber lengths were 1.9 and 4.83 mm in the orbital and global layers, respectively, approximately 10% and 24% of the total origin-to-insertion muscle lengths. In addition, individual myofibers continuously changed their intrafascicular relationships over their lengths. The density and distribution of NMJs in normal EOMs are more extensive than previously described. Individual myofibers are significantly shorter than the tendon-to-tendon muscle length in both muscle layers. Botulinum toxin results in a doubling of NMJ density. NMJ localization in normal EOMs has ramifications for understanding eye movement control, but it is also important when surgical or pharmacologic intervention is used for the treatment of strabismus, nystagmus, or other eye muscle disorders.

Strabismus in adults with uveal melanoma following episcleral plaque brachytherapy

To ascertain the incidence of persistent strabismus in patients treated with plaque brachytherapy and its subsequent treatment. A single center retrospective case note review of adult patients with persistent diplopia or strabismus following plaque brachytherapy for all types of intraocular tumors between 1996 and 2004. A total of 929 consecutive adults underwent plaque brachytherapy during the study period at a single center. Sixteen patients (1.7%) with treated uveal melanoma developed persistent diplopia or strabismus. In 11 patients (69%) the timing of onset was in the first year, in 2 (13%) in the second year, and one each (6% each) in years 5, 7, and 8. Two patients (13%) did not require any intervention. Fourteen patients (88%) required treatment: 7 (50%) were treated with prisms only, 3 (21%) underwent botulinum toxin (BTXA) injections, and 4 (29%) were treated with extraocular muscle surgery (3 required one operation and one required 2 procedures). The incidence of ocular motility disorders following plaque brachytherapy in our cohort was 1.7% over 8 years and we include this in the consent process for conservative treatment of intraocular tumors. Options for treatment for persistent diplopia or strabismus include prisms, botulinum toxin injection, or surgery.