Factors associated with the use of botulinum toxin injections for adult strabismus in the IRIS Registry.

This cross-sectional study used data from a large nationwide registry to describe the factors associated with use of botulinum toxin injections for adults with strabismus in the United States. Botulinum toxin injections were performed on 3.1% of adults undergoing an intervention for strabismus between 2013 and 2020. Adults treated with botulinum toxin injections were more likely to be older and female. Compared to non-Hispanic White patients, non-Hispanic Black patients were three times less likely to receive treatment with botulinum toxin after adjusting for age, sex, geographic region, and type of insurance. Efforts to understand the factors contributing to disparities in the use of botulinum toxin for strabismus may lead to opportunities for more equitable access to this intervention.

Golden Indications and an Overview on the Use of Botulinum Toxin in Strabismus.

Botulinum toxin A (BTXA) is considered a pharmacological agent that may provide an alternative treatment to surgery in strabismus. It can be used as both a diagnostic and therapeutic agent in various concomitant, paralytic, and restrictive disorders. The major advantage of BTXA treatment is that it is non-invasive and does not impact the patient's chance for future surgery in case of an unfavorable response. In some selected disorders, BTXA has become the primary choice of treatment, whereas surgery is found to be more effective in others. Accumulated knowledge and experience have demonstrated that BTXA is more than merely an alternative treatment and has additional specific indications such as in unstable deviations and as an adjunct to surgery. Patients with recurrent deviations despite multiple surgeries are also good candidates for BTXA treatment. Although the major expectation is to obtain a permanent result, BTXA can also be used as a maintenance treatment. This paper mainly focuses on the current indications for the use of BTXA in strabismology, with special emphasis on ideal first-choice applications referred to as "golden indications," within the scope of the author's own experience with the use of BTXA over 30 years.

Treatment of strabismus and blepharospasm with Botox (onabotulinumtoxinA): Development, insights, and impact.

Strabismus, deviation of the ocular alignment, can adversely affect quality of life and activities of daily living. Surgery was the prior standard of care for strabismus, but up to 40% of patients required additional surgeries. This need for more effective and less invasive treatment, along with the convergence of other events such as the development of electromyography, purification of botulinum toxin A, and the finding that injection of botulinum toxin type A could paralyze the hind limbs of chicks, led Dr. Alan Scott to investigate injection of his formulation for strabismus. The positive results of initial trials in monkeys segued to human trials with observations of alignment improvements and few adverse events. The success of botulinum toxin type A in the treatment of strabismus led to interest in its use to treat other skeletal muscles, particularly in blepharospasm, a type of focal dystonia involving eyelid spasms and involuntary eye closure that lacked an effective pharmacological treatment. Patient groups helped to increase awareness of this novel treatment, and results from clinical trials confirmed its effectiveness. Dr. Scott's formulation, then known as Oculinum, received its first Food and Drug Administration approvals in 1989 for strabismus and blepharospasm. Allergan acquired Oculinum in 1991, renaming it Botox. These initial uses led to its application in a myriad of other indications as outlined in other articles of this supplement.

Botulinum toxin for the treatment of strabismus.

BACKGROUND: The use of botulinum toxin as an investigative and treatment modality for strabismus is well reported in the medical literature. However, it is unclear how effective it is in comparison with other treatment options for strabismus. OBJECTIVES: The primary objective was to examine the efficacy of botulinum toxin therapy in the treatment of strabismus compared with alternative conservative or surgical treatment options. This review sought to ascertain those types of strabismus that particularly benefit from the use of botulinum toxin as a treatment option (such as small angle strabismus or strabismus with binocular potential, i.e. the potential to use both eyes together as a pair). The secondary objectives were to investigate the dose effect and complication rates associated with botulinum toxin. SEARCH METHODS: We searched CENTRAL, MEDLINE, Embase, LILACS and three trials registers on 6 July 2022, together with reference checking to identify additional studies. We did not use any date or language restrictions in the electronic searches for trials. SELECTION CRITERIA: We planned to include randomized controlled trials (RCTs) comparing botulinum toxin with strabismus surgery, botulinum toxin alternatives (i.e. bupivacaine) and conservative therapy such as orthoptic exercises, prisms, or lens therapy for people of any age with strabismus. All relevant RCTs identified in this update compared botulinum toxin with strabismus surgery. DATA COLLECTION AND ANALYSIS: We used standard methods expected by Cochrane and assessed the certainty of the body of evidence using GRADE. MAIN RESULTS: We included four RCTs with 242 participants that enrolled adults with esotropia or exotropia, children with acquired esotropia, and children with infantile esotropia. The follow-up period ranged from six to 36 months. Two studies were conducted in Spain, and one each in Canada and South Africa. We judged the included studies to have a mixture of low, unclear and high risk of bias. We did not consider any of the included studies to be at low risk of bias for all domains. All four studies reported the proportion of participants who improved or corrected strabismus, defined as ≤ 10 prism diopters (PD) at six months (two studies) or ≤ 8 PD at one year (two studies). Low-certainty evidence suggested that participants treated with the surgery may be more likely to improve or correct strabismus compared with those who treated with botulinum toxin (risk ratio (RR) 0.72, 95% confidence interval (CI) 0.53 to 0.99; I² = 50%; 4 studies, 242 participants; low-certainty evidence). One study, which enrolled 110 children with infantile esotropia, suggested that surgery may reduce the incidence of additional surgical intervention required, but the evidence was very uncertain (RR 3.05, 95% CI 1.34 to 6.91; 1 study, 101 participants; very low-certainty evidence). Two studies conducted in Spain compared botulinum toxin with surgery in children who required retreatment for acquired or infantile esotropia. These two studies provided low-certainty evidence that botulinum toxin may have little to no effect on achieving sensory fusion (RR 0.88, 95% CI 0.63 to 1.23; I² = 0%; 2 studies, 102 participants) and stereopsis (RR 0.86, 95% CI 0.59 to 1.25; I² = 0%; 2 studies, 102 participants) compared with surgery. Three studies reported non-serious adverse events. Partial transient ptosis (range 16.7% to 37.0%) and transient vertical deviation (range 5.6% to 18.5%) were observed among participants treated with botulinum toxin in three studies. In one study, 44.7% participants in the surgery group experienced discomfort. No studies reported serious adverse events or postintervention quality of life. AUTHORS' CONCLUSIONS: It remains unclear whether botulinum toxin may be an alternative to strabismus surgery as an independent treatment modality among certain types of strabismus because we found only low and very low-certainty evidence in this review update. Low-certainty evidence suggests that strabismus surgery may be preferable to botulinum toxin injection to improve or correct strabismus when types of strabismus and different age groups are combined. We found low-certainty evidence suggesting botulinum toxin may have little to no effect on achievement of binocular single vision compared with surgery in children with acquired or infantile esotropia. We did not find sufficient evidence to draw any meaningful conclusions with respect to need for additional surgery, quality of life, and serious adverse events. We identified three ongoing trials comparing botulinum toxin with conventional surgeries in the varying types of strabismus, whose results will provide relevant evidence for our stated objectives. Future trials should be rigorously designed, and investigators should analyze outcome data appropriately and report adequate information to provide evidence of high certainty. Quality of life and cost-effectiveness should be examined in addition to clinical and safety outcomes.

Long-Term Effects of Botulinum Toxin A for Horizontal Concomitant Strabismus in Chinese Children.

INTRODUCTION: For childhood strabismus, early surgical intervention improves both motor and sensory outcomes. Botulinum toxin type A (BTX-A) injection is an alternative to incisional surgery that is fast, less invasive, and preserves a more normal biomechanical construct. This study was undertaken to assess the safety and effectiveness of BTX-A for horizontal concomitant strabismus in children in our institution. PATIENTS AND METHODS: Records of all children less than age 18 years with follow-up at least 12 months who were treated with BTX-A for horizontal concomitant strabismus at Beijing Children's Hospital between December 2014 and February 2021 were reviewed retrospectively. Bilateral injections of BTX-A (Henli, 1.25 IU to 5 IU/0.1 ml) were made into the medial or lateral rectus muscles according to the angle of deviation. Reinjection was permitted if the initial alignment was not satisfactory within 1 to 6 months post-injection. Motor success was defined as a final misalignment ≤10 PD. Sensory success was defined as the presence of any evidence of sensory fusion, distance stereopsis, or near stereopsis at the last visit. RESULTS: Seventy-one patients were included. Fifty-two had esotropia, and 19 had exotropia. There was a significant decrease in the angle of deviation in all treated patients. The overall motor success rate was 60.6%. The motor success rate was highest in children with esotropia <50 PD (81.5%). Motor success was better for children with partially accommodative esotropia and acquired non-accommodative esotropia (80%, 83.3%, respectively) than for children with infantile esotropia (47.4%). Compared with the esotropia group, the fusion was significantly higher in the exotropia group (p = .007), and the proportion of patients with stereoacuity of better than 100 sec arc was higher also in the exotropia group (71.4%, p = .007), evidence of sensory outcomes were significantly better in the exotropia group. Complications were few. Twenty patients (28.2%) developed transient ptosis after injections; transient vertical deviations were seen in 3 patients (4.2%); and subconjunctival hemorrhage was seen in 5 patients (7%). CONCLUSIONS: BTX-A appears to be an effective treatment for the management of horizontal strabismus with motor outcomes best in children with acquired smaller-angle esodeviations. Children with exodeviations had better sensory outcomes in this cohort. A randomized controlled study comparing incisional surgery to BTX-A will be important for guiding future treatment decisions.

Evaluation of the Perioperative Effects of Dexmedetomidine and Midazolam-Ketamine Premedication in Strabismus Surgery.

PURPOSE: To evaluate the effects of intranasal dexmedetomidine and midazolam-ketamine combination for premedication on sedation quality, oculocardiac reflex development, mask tolerance, and separation from parents in children who would undergo strabismus surgery. METHODS: A total of 74 patients aged 2 to 11 years, were divided into two groups. The dexmedetomidine group (n = 37) received 1 mcg/kg of dexmedetomidine and the midalozam-ketamine group (n = 37) received 0.1 mg/kg of midazolam and 7.5 mg/kg of ketamine combination intranasally. Mean arterial pressure, peripheral oxygen saturation, Ramsay Sedation Scale values, and heart rate were recorded before and after the premedication. The children's separation from the family scores were evaluated and recorded. The mask compliance was evaluated and recorded. Patients who developed oculocardiac reflex and were administered atropine were recorded. In the postoperative period, nausea and vomiting, recovery times, and postoperative agitation were evaluated. RESULTS: Ramsay Sedation Scale scores, mask acceptance, and family separation scores were similar in both groups (P > .05). Oculocardiac reflex was observed more in the dexmedetomidine group (P = .048). Atro-pine requirement and postoperative nausea and vomiting rates were similar in both groups (P > .05). Mean arterial pressures and heart rates were significantly lower in the dexmedetomidine group during the pre-medication period. The recovery time was longer in the midazolam-ketamine group (P < .001). The incidence of postoperative agitation was significantly lower in the midazolam-ketamine group (P = .001). CONCLUSIONS: The sedation efficacy of intranasal dexmedetomidine and midazolam-ketamine combination that were given in premedication was similar. Oculocardiac reflex was observed more with dexmedetomidine. The recovery time was prolonged in the midazolam-ketamine group, but postoperative agitation was observed less. [J Pediatr Ophthalmol Strabismus. 2023;60(6):427-434.].

Success rates of botulinum toxin in different types of strabismus and dose effect.

OBJECTIVE: To determine the effect of botulinum toxin in different types of strabismus and analyze its dose effect. DESIGN: This was an interventional clinical study performed in a tertiary care university hospital. METHODS: Eighty six patients treated with botulinum toxin for strabismus were included. Main outcome measures involved success of botulinum toxin, alignment change per unit of toxin, and dose effect on complications and outcomes. RESULTS: Success rates were 31% for infantile esotropia, 25% for partially accommodative esotropia, 61.5% for residual esotropia, 25% for third cranial nerve paralysis, 13.3% for sixth cranial nerve paralysis, 75% for Duane retraction syndrome, and 38.5% for nonaccomodative esotropia. Improvement in deviation size after botulinum toxin treatment was significant in patients with infantile esotropia (p = 0.001), residual esotropia (p = 0.001), and nonaccomodative esotropia (p = 0.03). Mean deviation change per 1 unit of toxin was 2.7 ± 2.4 prism diopters (PD) with a single injection and 2.1 ± 1.9 PD with multiple injections. A 3.32 PD of early deviation change with botulinum toxin corrected 1 PD of final deviation. Success rate was not correlated with age (r = 0.040, p = 0.8), sex (r = -0.083, p = 0.6), mean dose (r = -0.149, p = 0.35), or total dose (r = 0.165, p = 0.29) but was significantly correlated with deviation size (ß = -0.077, p = 0.0001). Complications were not associated with the dose of botulinum toxin (p > 0.05). CONCLUSIONS: Botulinum toxin has variable outcomes in different types of strabismus. Still, it reduces the deviation size in most patients, thus allowing for a smaller amount of subsequent muscle surgery. Early overcorrection is a more powerful indicator of better outcome than postinjection duction deficit.

Applications of bupivacaine in the non-surgical treatments of strabismus: a review.

Bupivacaine (BUP) is an anesthetic from the family of aminoacyl anesthetics and has the highest myotoxicity among other groups of anesthetics. Intramuscular injection of BUP first causes acute libriform lysis and subsequently with the regeneration process, stronger myofibrils are formed within 3-4 weeks. Satellite cells, which are actually myogenic stem cells, are preserved in the early stage and during the destruction of muscle fibers. In fact, these cells are responsible for the subsequent regeneration of fibers. BUP is one of the few medicines that is able to increase muscle strength. In animal studies on rabbits, a decrease has been observed in the diameter of the global layer in the first week and an increase in type-I myosin occurs after 60 days, especially in the global muscle layer. There are numerous studies according to BUP injection for the non-surgical management of horizontal strabismus. To intensify the effects of the injection, botulinum toxin injection can also be used simultaneously in the antagonist muscles. In general, although the rate of improvement in strabismus varied among different studies, BUP injection alone corrects about 5-8 prism diopters. Together with botulinum toxin, BUP corrects about 15 prism diopters. The stability of this improvement is up to 10 years after injection. No significant difference has been observed in response rate between patients with esotropia and exotropia. Unlike the large molecule of botulinum toxin, which spreads slowly to its site of action, the BUP molecule is small and must be in direct contact with myofibrils before absorption into the bloodstream to exert its effect. Therefore, the injection volume should be about 3 cc with a concentration of 0.75 g per deciliter. Although BUP is promising non-surgical strabismus management, especially in small angle and residual horizontal strabismus, however, it has its own limitations. The need for direct infusion of a relatively large volume of BUP may be one of its major drawbacks that limits its usage in an office method.

Strabismus Surgery: A Retrospective Comparison of Different Postoperative Treatment Regimes to Prevent Infections.

BACKGROUND: As studies have shown postsurgical polyvidone-iodine to be at least equal to postsurgical topical antibiotics, our postsurgical care regime was adjusted accordingly in 2017. Here, we retrospectively compared the postsurgical infection rate in patients who underwent strabismus surgery prior to and following this change in regimen in a routine clinical setting. PATIENTS AND METHODS: In this retrospective and explorative study, data from 162 adult patients who had undergone strabismus surgery was extracted from files: 98 patients who had received topical gentamycin in a combination ointment with steroid (postsurgery) followed by 1 week of topical gentamycin with nonsteroidal antiphlogistic eye drops for 1 week (group 1) and 64 who had received polyvidone-iodine once immediately postsurgically instead. We compared both groups' postsurgical healing period regarding occurrence of bacterial conjunctival infection and conjunctival swelling and redness as well as other complications. Data were extracted from the entries of the routine follow-up dates on postsurgical days 1, 7, and at 3 months. RESULTS: Mean age of group 1 was 49 years and 51 years in group 2. There was no significant difference between the kind of surgeries (recessions/resections) or the number of patients who had undergone a reoperation. There was no significant difference between the groups for any of the endpoints analyzed at any of the three regular follow-up dates. From group 1, 12.04% and from of group 2, 6.25% showed bacterial conjunctivitis 1 week postsurgery. There was no endophthalmitis. CONCLUSION: Topical polyvidone-iodine given once at the end of strabismus surgery is a good alternative to topical antibiotics with a comparable healing progress. It carries a comparable risk of infection as seen with a 1-week course of topical antibiotics. The advantages are less manipulation of the eye, no bacterial resistance caused, and cost efficiency. In addition, the lack of anti-inflammatories given in group 2 did not pose a disadvantage.

Tratamiento farmacológico del estrabismo / Pharmacological treatment of strabismus

La cirugía de la musculatura extraocular ha sido el estándar de atención para tratamiento quirúrgico del estrabismo por más de un siglo. A pesar del gran desarrollo técnico de la cirugía de estrabismo en la actualidad, la utilización de microscopio quirúrgico, el diseño novedoso del instrumental quirúrgico, la calidad de la sutura no reabsorbible; los avances en equipamiento y fármacos anestésicos, la misma no está exenta de complicaciones quirúrgicas, además del tiempo de recuperación que necesita el paciente para reincorporarse a sus actividades sociales, han propiciado una búsqueda permanente del tratamiento farmacológico para el estrabismo. El objetivo de esta revisión bibliográfica es analizar las distintas alternativas farmacológicas disponibles como tratamiento del estrabismo. Para su confección se consultó textos completos y artículos en idiomas español e inglés, disponible en algunas bases de datos. Concluimos que aunque se han estudiado numerosos fármacos, la toxina botulínica que es la más conocida y utilizada mundialmente, seguida de la bupivacaína. Encontramos otros como la IGF I y II (Insuline Growing Factor), capaces de generar un efecto de reforzamiento de la actividad muscular. Y otros que "debilitan" la musculatura extraocular, incluyen la mAb35-Rubicina, BMP4 (Proteína morfogénica ósea). Se continúa su investigación en la actualidad(AU)

Extraocular musculature surgery has been the standard of care for surgical treatment of strabismus for more than a century. Despite the great technical development of strabismus surgery today, the use of a surgical microscope, the novel design of surgical instruments, the quality of the non-absorbable suture; Advances in anesthetic equipment and drugs, it is not exempt from surgical complications, in addition to the recovery time that the patient needs to return to their social activities, have led to a permanent search for pharmacological treatment for strabismus. The objective of this bibliographic review is to analyze the different pharmacological alternatives available as a treatment for strabismus. For its preparation, full texts and articles in Spanish and English languages were consulted, available in some databases. We conclude that although numerous drugs have been studied, botulinum toxin, which is the best known and used worldwide, followed by bupivacaine. We find others such as IGF I and II (Insuline Growing Factor), capable of generating an effect of reinforcing muscle activity. And others that "weaken" MOE include mAb35-Rubicin, BMP4 (Bone Morphogenic Protein). His research is continuing today(AU)

The efficacy of bupivacaine for the treatment of strabismus.

INTRODUCTION: Bupivacaine (BPX) is a widely used local anesthetic. Ophthalmologists have found a unique use of BPX to alter the elasticity and contractile properties of extraocular muscles to straighten strabismus. The utilization of BPX to treat strabismus has been well documented. The purpose of this review is to examine the overall efficacy of BPX when used in isolation for the treatment of strabismus, based on the published literature. METHODOLOGY: A literature search was carried out to identify papers published between the years 1980 and 2021, which examined the impact of BPX as a stand-alone treatment for strabismus. RESULTS: Eight articles were identified as matching the inclusion criteria. The authors reported that volumes of ≤1.00 mL are unlikely to be significant enough to improve ocular alignment and increasing volume strength is associated with greater changes in ocular alignment. The overall change in ocular alignment varied from 0-16PD between the different studies included, with similar effects being noted for deviations between 10 and 20PD and deviations as large as 55PD. It has been documented that there is no significant difference in the outcomes of BPX treatment for esotropia and exotropias, but some clinical differences have been noted with esotropia (or the lateral rectus) responding better to BPX. Bupivacaine has been demonstrated to be less effective in patients with chronic nerve palsies. All but one author documented increases in the injected muscle's volume and maximum cross-sectional area from month one to three followed thereafter by a gradual decrease in both measurements. It was noted that despite the reduction in both measurements, the change in ocular alignment continued to show improvements. No sight-threatening or persistent complications were reported within any of the studies or case reports included within this review. In the interest of patient experience, the majority of patients reported that BPX improved their eye alignment, while a third reported feelings of discomfort during the procedure. CONCLUSION: Bupivacaine is a viable option for the treatment of small angle deviations and is not recommended for use in long-standing cranial nerve palsies or those associated with atrophy. Care is needed in determining the required dose to avoid the need for re-injection and impacting patient experience.

Binocular Visual Rehabilitation in Paralytic Strabismus by Botulinum A Toxin Chemodenervation.

PURPOSE: To investigate the effect of botulinum A toxin (BTXA) chemodenervation in paralytic strabismus patients without surgical correction. METHODS: A retrospective chart review of 51 patients who were diagnosed as paralytic strabismus and underwent BTXA chemodenervation was performed. The patients were divided into four groups according to the cause of paralytic strabismus of vasculopathy, neoplasm, trauma, and idiopathic. They were also divided into two groups of early and late treatment according to the initiation time of BTXA chemodenervation after the onset of strabismus (3 months), and of the initial strabismus type of exotropia and esotropia. We investigated the changes of angle of deviation and diplopia after BTXA chemodenervation. RESULTS: The average deviation of angles decreased by 25.2 prism diopter (PD) (35.1 to 9.9 PD) in total patients, and the overall success rate was 64.7% (33 by 51), and the there was no statistically significant difference in success rate between each group divided by the cause of paralytic strabismus. According to the treatment timing, the deviation of the angle decreased by 28.0 PD (36.8 to 8.8 PD) in the early treatment group, and 21.3 PD (33.5 to 12.2 PD) in late treatment group at the time of the last postinjective follow-up. According to the initial strabismus type, the average angle of deviation decreased by 20.3 PD (35.6 to 15.3 PD) in exotropia group by cranial nerve 3 palsy, and 24.4 PD (32.5 to 8.1 PD) in esotropia by cranial nerve 6 palsy. CONCLUSIONS: BTXA chemodenervation reduced the angle of deviation and the number of patients with diplopia regardless of the cause of paralytic strabismus. Early BTXA chemodenervation can be considered as the first treatment of choice in paralytic strabismus, especially in esotropia patients.

Botulinum Toxin Injection for the Treatment of Strabismus: A Report by the American Academy of Ophthalmology.

PURPOSE: To review the available evidence comparing the effectiveness of extraocular muscle botulinum toxin type A (BTXA) injection with eye muscle surgery for restoring ocular alignment in children and adults with nonparalytic, nonrestrictive horizontal strabismus. METHODS: Literature searches in the PubMed Cochrane Library, and clinical trial databases with no date restrictions, but limited to articles published in English, were conducted last on January 10, 2021. The searches yielded 515 citations, 40 of which were reviewed in full text by the first author. Fourteen articles met the criteria for inclusion (randomized or nonrandomized comparative studies, or case series with a minimum 50 patients; evaluating extraocular muscle BTXA injection for initial or repeat treatment of horizontal, nonparalytic, nonrestrictive strabismus; with at least 6 months of follow-up) and were graded by a methodologist. RESULTS: The 14 included studies consisted of 2 randomized clinical trials, 3 nonrandomized comparative studies, and 9 case series. All 5 comparative studies were graded level II evidence, and the 9 case series were graded level III evidence. Successful motor outcomes after BTXA injection were relatively consistent across 4 of the 5 comparative studies at 60%, when adjustment was made for differential selection bias in 1 of the studies. In the 4 studies, successful motor outcomes after surgery ranged from 66% to 77% with a mean follow-up of 23 to 75 months, and the outcomes were not significantly different from those after BTXA injection. In the fifth level II study, success was significantly higher with BTXA injection than with surgery (94% vs. 72%). The level III BTXA case series demonstrated higher motor success rates of 87% to 89% when children were treated in 2 muscles at a time; rates were lower in adults treated with single-muscle BTXA injection. CONCLUSIONS: Extraocular muscle injection of BTXA achieves a high rate of successful motor alignment, comparable with that achieved after eye muscle surgery for nonparalytic, nonrestrictive horizontal strabismus. Good alignment may require multiple BTXA injections, and it is not yet clear whether sensory outcomes are equivalent for BTXA injections versus eye muscle surgery in young children.

Herpes simplex keratoconjunctivitis in the immediate postoperative period after strabismus surgery.

The authors describe the case of bilateral herpes simplex keratoconjunctivitis (HSK) following uncomplicated 7 mm bilateral lateral rectus recessions in a 3-year-old child. The recovery was initially unremarkable, and the standard postoperative drops of dexamethasone and chloramphenicol (non-preservative free) were prescribed. The child presented 8 days postoperatively with fever, right upper lid swelling and ptosis. She was admitted for intravenous antibiotics for suspected pre-septal cellulitis. Over the next 2 days, she deteriorated with bilateral lid involvement. An examination under anesthesia (EUA) revealed bilateral corneal epithelial (dendritic and geographical) ulcers with conjunctival erosions and pseudo membranes prompting a diagnosis of HSK. This was confirmed by polymerase chain reaction (PCR) testing. The child recovered within 2 weeks after starting oral and topical antiviral medication. This case highlights the importance of EUA in infections not responding to standard treatment. Although HSK is known to occur after topical steroid use and ocular surgery, we were not able to find any other cases in the literature and believe this is the first reported case of bilateral HSK in the immediate postoperative period after strabismus surgery.

Use of Botulinum Toxin in Ophthalmology.

Botulinum toxin is an important treatment for many conditions in ophthalmology, including strabismus, nystagmus, blepharospasm, hemifacial spasm, spastic and congenital entropion, corneal exposure, and persistent epithelial defects. The mechanism of action of botulinum toxin for both strabismus and nystagmus is the neuromuscular blockade and transient paralysis of extraocular muscles, but when botulinum toxin is used for some forms of strabismus, a single injection can convey indefinite benefits. There are two unique mechanisms of action that account for the long-term effect on ocular alignment: (1) the disruption of a balanced system of agonist-antagonist extraocular muscles and (2) the reestablishment of central control of alignment by the binocular visual system. For other ocular conditions, botulinum toxin acts through transient paralysis of periocular muscles. Botulinum toxin is a powerful tool in ophthalmology, achieving its therapeutic effects by direct neuromuscular blockade of extraocular and periocular muscles and by unique mechanisms related to the underlying structure and function of the visual system.

Evolving trends in strabismus following retinal surgery: is there still a role for botulinum toxin?

Purpose Ocular motility disturbances following retinal detachment surgery are well documented, resulting in ocular misalignment and disabling diplopia. Interestingly, there has been a downward trend over the last decade across the United Kingdom with the evolution of refined vitrectomy techniques and instrumentation. We aim to report our updated experience on factors influencing botulinum toxin outcomes in view of the trend toward vitrectomy. Methods The Moorfields strabismus service carried out a follow-up retrospective study of all subjects that received botulinum toxin for retinal surgery-related strabismus at our center over an eleven-year period. All new onset constant or intermittent strabismus following retinal detachment surgery were included. Botulinum toxin response was stratified to good and poor. Results 32 patients fulfilled our criteria, with a mean follow-up of 20 months. The majority were vitrectomised eyes (62%), presented with diplopia (60%) and exotropia (66%). All isolated and combined vertical deviations (18%) were noted among cryobuckled eyes only. Baseline largest mean horizontal deviation was 49 and 51 prism diopters (PD) among the good and poor responders, respectively. A statistically and clinically significant reduction in the horizontal angle of deviation was noted among the good (p < .0001) responders, requiring a mean of six injections, in comparison to the poor responders (p = .03). Of the good responders, five patients (16%) with decompensated phorias regained fusion control. A small number of complications (15%) were noted, the most marked being intractable diplopia in a good responder (3%) with failure to fuse. Conclusions Botulinum toxin is a useful treatment modality, particularly when surgical options are limited. It can restore binocularity in patients with preexisting fusion potential. Ocular cosmesis can be achieved but requires ongoing injections. Barriers to fusion restoration include multiple retinal surgeries, persistent macula pathology and central-peripheral retinal rivalry. This highlights the need for rigorous baseline macula assessment to allow a tailored approach when considering botulinum toxin therapy for strabismus.

Instillation of 5% Povidone-Iodine Ophthalmic Drops Decreases the Respiratory Rate in Children Undergoing Strabismus Surgery: A Randomized Controlled Trial.

PURPOSE: To investigate the effects of topical application of ophthalmic 5% povidone-iodine eye drops, which has been reported to cause apnea in spontaneously breathing children during general anesthesia. METHODS: The authors conducted a randomized, controlled, single-blinded study comparing the effect of balanced salt solution eye drops and povidone-iodine eye drops on respiration in spontaneously breathing children during general anesthesia with sevoflurane via a laryngeal mask airway. Fifty patients received balanced salt solution eye drops and 50 patients received 5% povidone-iodine eye drops. RESULTS: None of the control patients had a significant change in respiration. Thirty of the 50 (60%) povidone-iodine patients had a slowing of respiration within the first 6 breaths after eye drop instillation (P < .001). The median time of respiratory pause in those 30 patients was 18.5 seconds (range: 4.36 to 96.2 seconds). Among the povidone-iodine patients, children with a history of a prior tonsillectomy and adenoidectomy and/or bilateral myringotomy had a 7.2 times greater chance of experiencing a change in respiration after instillation of the povidone-iodine eye drops. CONCLUSIONS: Topical application of 5% povidone-iodine eye drops causes a slowing and pause in spontaneous ventilation in a majority of children prior to strabismus surgery. This may represent activation of the diving reflex. [J Pediatr Ophthalmol Strabismus. 2019;56(6):378-382.].

The Role of Botulinum Toxin in the Treatment of Strabismus.

Purpose: To perform a systematic review of the application of botulinum toxin A (BTA) in the management of strabismus in the adult and pediatric populations. Materials and methods: A systematic literature search was performed using the Medline database. Results: In 1989, with the FDA approval of botulinum toxin (onabotulinum toxin A, or BTA) for the treatment of strabismus, patients were provided with an alternative to surgical recession. In this review, we discuss the uses of BTA in the treatment of acute onset comitant esotropia or smaller angle esotropia and as an adjunct to surgery for larger angle esotropia or sixth nerve palsy. Its uses are also explored in intermittent exotropia and vertical strabismus, including thyroid-associated orbitopathy, fourth nerve palsies, and other orbital pathology. Discussion: Despite its transient kinetics, BTA can have permanent effects on ocular alignment, promoting binocularity and reduction of diplopia, and can serve as a primary treatment or a muscle sparing option in patients at risk of anterior segment ischemia or need for future surgeries.

The Use of Botulinum Toxin in Strabismus Treatment.

There is a long and extensive experience with the use of Botulinum Toxin type A (BoNT-A) injection in the treatment of different types of strabismus and oculomotor palsies. The frequency of its use varies depending on the country and institution. It is a short procedure, may reduce general anesthesia exposure, causes minimal scarring compared to surgery, and can be proposed as an early treatment in unstable strabismus. Over many years, the experience of using BoNT-A indications has been refined and new applications have been reported. The use of BoNT-A in the postoperative period, after strabismus surgery or during surgery, can also be beneficial.

[Botulinumtoxin in Ophthalmology]. / Botulinumtoxin in der Augenheilkunde.

Botulinum toxin has been first applied in ophthalmology (as treatment for strabismus) and is nowadays widely used in many clinical areas. Currently the main application in ophthalmology is the treatment of essential blepharospasm and hemifacial spasm. Other important indications for botulinum toxin in ophthalmology are eyelid retraction in Graves' disease and the induction of protective ptosis in lagophthalmos or corneal diseases.