Strabismus

Strabismus Publications

Oke I, Hall N, Elze T, Miller JW, Lorch AC, Hunter DG, Hunter DG. Adjustable Suture Technique Is Associated with Fewer Strabismus Reoperations in the Intelligent Research in Sight Registry. Ophthalmology 2022;129(9):1028-1033.Abstract
PURPOSE: To compare the reoperation rates after strabismus surgery with and without the adjustable suture technique. DESIGN: Retrospective cohort study. PARTICIPANTS: Patients 18 years of age or older in the Intelligent Research in Sight (IRIS®) Registry who underwent strabismus surgery between January 1, 2013, and December 31, 2018. METHODS: Data were collected from the electronic health records of practices participating in the IRIS Registry. The primary exposure of interest was use of the adjustable suture technique, identified by Current Procedural Terminology coding. MAIN OUTCOME MEASURES: The primary outcome was repeat strabismus surgery within 1 year of initial strabismus surgery. Odds ratios (ORs) were derived from a multivariable logistic regression model evaluating the association between the use of adjustable sutures and reoperation rate, adjusting for patient demographics and surgical factors. RESULTS: A total of 34 872 patients who underwent strabismus surgery during the study interval were identified: 72% underwent horizontal muscle surgery, 17% underwent vertical muscle surgery, and 11% underwent combined horizontal and vertical muscle surgery. Adjustable sutures were used in 18% of patients. The overall reoperation rate within 1 year of strabismus surgery was 7.7%. The 1-year reoperation rate was 6.0% for patients treated with adjustable sutures and 8.1% for patients treated without adjustable sutures (P < 0.001). The multivariable regression model revealed a statistically significant 30% decrease in the odds of reoperation within 1 year of surgery when adjustable sutures were used (OR, 0.70; 95% confidence interval [CI], 0.62-0.78), a 40% increase in those with a history of prior strabismus surgery (OR, 1.40; 95% CI, 1.28-1.53), and a 9% increase per decade of age at surgery (OR, 1.09; 95% CI, 1.06-1.11). CONCLUSIONS: In adults cared for in practices participating in the IRIS Registry, the adjustable suture technique was associated with a significantly lower reoperation rate within 1 year of undergoing horizontal or combined horizontal and vertical strabismus surgery. Adjustable suture use in vertical strabismus surgery alone did not reduce the 1-year reoperation rate significantly. A history of prior strabismus surgery was associated with increased odds of reoperation.
Oke I, Heidary G, Mantagos IS, Shah AS, Hunter DG. A decline in the strabismus surgical experience of ophthalmology residents in the United States from 2010 to 2019. J AAPOS 2022;Abstract
Subspecialty exposure during residency can influence the future pursuit of fellowship training. In this study, we compared the trends in strabismus surgical experience reported by graduating ophthalmology residents in the United States with other categories of ophthalmic surgery. Over the 10-year period (2010-2019), there was a decline in the total number of strabismus procedures performed during residency by ophthalmology residents graduating in a given year (1.4 fewer cases per year; 95% CI, 1.1-1.6 [P < 0.001]). Although several surgical categories experienced a decrease in cases performed in the assistant role, strabismus surgery was the only category with a decrease in cases performed in the surgeon role (0.4 fewer cases per year; 95% CI, 0.3-0.5 [P < 0.001]).
Bothun ED, Shainberg MJ, Christiansen SP, VanderVeen DK, Neely DE, Kruger SJ, Cotsonis G, Lambert SR, Lambert SR. Long-term strabismus outcomes after unilateral infantile cataract surgery in the Infant Aphakia Treatment Study. J AAPOS 2022;Abstract
PURPOSE: To characterize long-term strabismus outcomes in children in the Infant Aphakia Treatment Study (IATS). METHODS: This study was a secondary data analysis of long-term ocular alignment characteristics of children aged 10.5 years who had previously been enrolled in a randomized clinical trial evaluating aphakic management after unilateral cataract surgery between 1 and 6 months of age. RESULTS: In the IATS study, 96 of 109 children (88%) developed strabismus through age 10.5 years. Half of the 20 children who were orthophoric at distance through age 5 years maintained orthophoria at distance fixation at 10.5 years. Esotropia was the most common type of strabismus prior to age 5 years (56/109 [51%]), whereas exotropia (49/109 [45%]) was the most common type of strabismus at 10.5 years (esotropia, 21%; isolated hypertropia, 17%). Strabismus surgery had been performed on 52 children (48%), with 18 of these (35%) achieving microtropia <10Δ. Strabismus was equally prevalent in children randomized to contact lens care compared with those randomized to primary intraocular lens implantation (45/54 [83%] vs 45/55 [82%]; P = 0.8). Median visual acuity in the study eye was 0.56 logMAR (20/72) for children with orthotropia or microtropia <10Δ versus 1.30 logMAR (20/400) for strabismus ≥10Δ (P = 0.0003). CONCLUSIONS: Strabismus-in particular, exotropia-is common irrespective of aphakia management 10 years following infant monocular cataract surgery. The delayed emergence of exotropia with longer follow-up indicates a need for caution in managing early esotropia in these children. Children with better visual acuity at 10 years of age are more likely to have better ocular alignment.
Oke I, Shah AS, Lorenz B, Basiakos S, Gokyigit B, Ugo Dodd M-M, Laurent E, Hunter DG, Goberville M, Elkamshoushy A, Tsai C-B, Orge F, Velez FG, Jeddawi L, Gravier N, Li N, Dagi LR, Dagi LR. Nasal Transposition of the Split Lateral Rectus Muscle for Strabismus Associated with Bilateral 3rd-Nerve Palsy. Am J Ophthalmol 2022;Abstract
PURPOSE: To determine success rate and complications associated with nasal transposition of the split lateral rectus muscle (NTSLR) for treating bilateral 3rd-nerve palsy. DESIGN: Retrospective, interventional case series METHODS: : Setting: International, multicenter registry Study population: All patients with bilateral 3rd-nerve palsy treated with NTSLR. OBSERVATION: Sensorimotor evaluations before and 6-months after unilateral or bilateral NTSLR. OUTCOME MEASURES: Post-operative horizontal alignment ≤ 15 prism diopters (PD), intraoperative technical difficulties, and vision-threatening complications. The association of patient demographics and surgical technique with each outcome was analyzed using multivariable logistic regression. RESULTS: Thirty-four patients were included with a median age of 46 years (Interquartile range [IQR], 25-54 years) at surgery. The most common etiologies were ischemic (29%), neoplastic (15%), and congenital (12%). NTSLR performed unilaterally with alternative surgery on the opposite eye (65%) resulted in a median post-operative exotropia of 18 PD (IQR, 7-35 PD), and when performed bilaterally (35%) resulted in post-operative exotropia of 14 PD (IQR, 5-35 PD). Success was achieved in 50% of cases, intra-operative technical difficulties reported in 18%, and vision-threatening complications occurred in 21%. Attachment of the lateral rectus muscle ≥ 10 mm posterior to the medial rectus insertion was associated with increased vision-threatening complications (OR, 9.0; 95% CI, 1.3-99). CONCLUSIONS: NTSLR can address the large-angle exotropia associated with bilateral 3rd-nerve palsy. Surgeons should be aware that posterior placement of the lateral rectus muscle can increase the risk of vision-threatening complications, particularly serous choroidal effusion.
White E, Walsh L. The impact of occlusion therapy and predictors on amblyopia dose-response relationship. Strabismus 2022;30(2):78-89.Abstract
This study aimed to calculate the dose-response relationship and predictors of visual acuity (VA) improvement following occlusion therapy at the IWK Health Center Eye Clinic and to add to amblyopia therapy dose-response relationship literature. A retrospective chart review was performed, considering patients who reached an occlusion therapy outcome at the IWK Eye Clinic between 2012 and 2019. The treatment outcome was defined as equal VA or stable VA for three consecutive clinical visits despite reported compliance. Subjective patching hours from parental reports, not prescribed hours, were used for statistical analyses. One hundred and thirty-four patients (66 females and 68 males) ages 2-11 years were included. Results showed a dose-response relationship of 224 hours/0.1logMAR increase in VA and total dose of 1344 hours for full-time occlusion and 504 hours for part-time occlusion was required to reach outcome VA. The fastest VA improvement occurred with younger age at treatment initiation, during the first 4 weeks of treatment, and in patients with strabismic and/or severe amblyopia. Classification of amblyopia, age, VA chart, initial distance VA (amblyopic eye), and treatment dose predicted the hour dose-response relationship. Dose-response relationship was faster in younger participants, in participants with strabismic and severe amblyopia, and during the first month of occlusion. Additionally, by creating a GLM model of dose-response relationship, relationship calculations can be performed. Therefore, an estimated timeline can be developed to allow allocation of clinical resources and to prepare patients for the treatment duration required and possibly increase treatment compliance.
Su T, Zhu P-W, Li B, Shi W-Q, Lin Q, Yuan Q, Jiang N, Pei C-G, Shao Y. Gray matter volume alterations in patients with strabismus and amblyopia: voxel-based morphometry study. Sci Rep 2022;12(1):458.Abstract
This study proposes the use of the voxel-based morphometry (VBM) technique to investigate structural alterations of the cerebral cortex in patients with strabismus and amblyopia (SA). Sixteen patients with SA and sixteen healthy controls (HCs) underwent magnetic resonance imaging. Original whole brain images were analyzed using the VBM method. Pearson correlation analysis was performed to evaluate the relationship between mean gray matter volume (GMV) and clinical manifestations. Receiver operating characteristic (ROC) curve analysis was applied to classify the mean GMV values of the SA group and HCs. Compared with the HCs, GMV values in the SA group showed a significant difference in the right superior temporal gyrus, posterior and anterior lobes of the cerebellum, bilateral parahippocampal gyrus, and left anterior cingulate cortex. The mean GMV value in the right superior temporal gyrus, posterior and anterior lobes of the cerebellum, and bilateral parahippocampal gyrus were negatively correlated with the angle of strabismus. The ROC curve analysis of each cerebral region confirmed the accuracy of the area under the curve. Patients with SA have reduced GMV values in some brain regions. These findings might help to reveal the potential pathogenesis of SA and its relationship with the atrophy of specific regions of the brain.
Heidary G, Aakalu VK, Binenbaum G, Chang MY, Morrison DG, VanderVeen DK, Lambert SR, Trivedi RH, Galvin JA, Pineles SL. Adjustable Sutures in the Treatment of Strabismus: A Report by the American Academy of Ophthalmology. Ophthalmology 2022;129(1):100-109.Abstract
PURPOSE: To review the scientific literature that evaluates the effectiveness of adjustable sutures in the management of strabismus for adult and pediatric patients. METHODS: Literature searches were performed in the PubMed database through April 2021 with no date limitations and were restricted to publications in English. The searches identified 551 relevant citations, of which 55 were reviewed in full text. Of these, 17 articles met the inclusion criteria and were assigned a level of evidence rating by the panel methodologist. The search included all randomized controlled studies regardless of study size and cohort studies of 100 or more patients comparing the adjustable versus nonadjustable suture technique, with a focus on motor alignment outcomes or reoperation rates. RESULTS: The literature search yielded no level I studies. Of the 17 articles that met the inclusion criteria, 11 were rated level II and 6 were rated level III. Among the 12 studies that focused on motor alignment outcomes, 4 small randomized clinical trials (RCTs) did not find a statistically significant difference between groups, although they were powered to detect only very large differences. Seven of 8 nonrandomized studies found a statistically significant difference in motor alignment success in favor of the adjustable suture technique, both overall and in certain subgroups of patients. Successful motor alignment was seen in both exotropia (in 3 studies that were not limited to children) and esotropia (in 1 study of adults and 2 of children). The majority of included studies that reported on reoperation rates found the rates to be lower in patients who underwent strabismus surgery with adjustable sutures, but this finding was not uniformly demonstrated. CONCLUSIONS: Although there are no level I studies evaluating the effectiveness of adjustable sutures for strabismus surgery, the majority of nonrandomized studies that met the inclusion criteria for this assessment reported an advantage of the adjustable suture technique over the nonadjustable technique with respect to motor alignment outcomes. This finding was not uniformly demonstrated among all studies reviewed and warrants further investigation in the development and analysis of adjustable suture techniques.
Oke I, Elhusseiny AM, Shah AS, Hunter DG. Botulinum Toxin Injection of the Inferior Oblique Muscles for V-Pattern Strabismus and Primary Position Hypertropia. Am J Ophthalmol 2022;235:32-37.Abstract
PURPOSE: To evaluate outcomes of botulinum toxin (BTX) injection of the inferior oblique (IO) muscle. DESIGN: Retrospective case series. METHODS: Setting: Single center, ophthalmology department at Boston Children's Hospital. STUDY POPULATION: All patients treated with IO muscle injection of BTX (onabotulinumtoxinA) between 2010 and 2020. OBSERVATION PROCEDURE: Sensorimotor evaluations at short-term (<2 months), medium-term (2-4 months), and long-term (≥4 months) intervals. OUTCOME MEASURE: Primary outcomes included median improvement in V-pattern strabismus and primary position hypertropia. Secondary outcomes included IO muscle overaction. Wilcoxon signed-rank tests were performed to identify differences before and after injection. RESULTS: Record review identified 20 patients with a median age of 4.5 (range, 1-69) years. Median BTX dose injected (31 IO muscles) was 5.0 (range, 3.0-7.0) units. Indications included V-pattern strabismus (N = 8), hypertropia (N = 7), or both (N = 5). Median long-term interval was 6.4 (range, 4.1-26.6) months. Injections were concurrent with treatment of horizontal strabismus in all but 3 cases. Median V-pattern magnitude changed from 10 prism diopters (PD) preoperatively to 0 PD short-term (P = .006) and 3.5 PD long-term (P = .34). Median hypertropia changed from 8.5 PD preoperatively to 1.5 PD short-term (P = .01) and 8 PD long-term (P = .87). Median IO muscle overaction grade improved significantly at short-term (P < .001) and long-term (P = .007) intervals. There were no complications associated with the IO muscle injections. CONCLUSIONS: BTX injection of the IO muscles can be a useful adjunct to the management of V-pattern strabismus. Intervention for primary position hypertropia may be helpful for short-term relief with no expectation of long-term benefit.
Scelfo C, Elhusseiny AM, Alkharashi M. Effect of inferior oblique myectomy on primary position when combined with lateral rectus recession for intermittent exotropia. Eur J Ophthalmol 2022;32(1):559-562.Abstract
PURPOSE: To evaluate the surgical success and need for adjustment due to overcorrection in patients who undergo inferior oblique myectomy (IOM) combined with lateral rectus recession (LRc) for intermittent exotropia in the setting of inferior oblique overaction. METHODS: A retrospective chart review was conducted of patients with intermittent exotropia who underwent LRc using adjustable sutures alone versus LRc combined with IOM between January 2010 and July 2018 at our institution. Binocular alignment was recorded before and within one week of surgery. Evaluation measures noted were surgical success (defined as distance alignment of ⩽10 prism diopters) and need for postoperative adjustment due to overcorrection. RESULTS: Of 48 patients, 24 underwent LRc alone and 24 underwent LRc combined with IOM; all 48 patients had adjustable sutures. Surgical success was significantly higher in the LRc alone group (91.6%) compared with the LRc with IOM group (62.5%) (p = 0.036). The need for postoperative adjustment due to overcorrection was also significantly higher in the LRc with IOM group (20.8%) compared with the LRc alone group (0%) (p = 0.049). CONCLUSIONS: In this study, more patients needed adjustment for overcorrection after undergoing LRc combined with IOM versus LRc alone. Since the tertiary action of the inferior oblique is abduction it is possible that, in patients with inferior oblique overaction, surgically weakening the inferior oblique causes more esodeviation and overcorrection. Thus, surgical correction of exotropia and inferior oblique overaction using LRc combined with IOM may lead to overcorrection and increased need for postoperative adjustment.
Hennein L, Robbins SL. Thyroid-Associated Orbitopathy: Management and Treatment. J Binocul Vis Ocul Motil 2021;:1-15.Abstract
Thyroid-associated orbitopathy (TAO) is a leading cause of orbital and strabismus symptoms in adults. Over the last decade, new treatments have greatly changed available options to alleviate symptoms and improve outcomes. This article discusses the pathophysiology and natural disease course of TAO, including when to pursue urgent treatment and when to consider other diagnoses. This article highlights the interventions that may alter the disease course and offers a comprehensive review on evidence-based interventions for both supportive therapy and systemic agents. The surgical strategies and principles for the treatment of TAO are discussed, including indications for combined surgical interventions and varying surgical techniques.
Shah AS, Ugo Dodd M-M, Gokyigit B, Lorenz B, Laurent E, Sadiq MAA, Tsai C-B, Gravier N, Goberville M, Basiakos S, Zurakowski D, Dagi LR, Dagi LR. Worldwide outcomes of nasal transposition of the split lateral rectus muscle for strabismus associated with 3rd-nerve palsy. Br J Ophthalmol 2021;Abstract
BACKGROUND/AIMS: To determine success rate and complications associated with nasal transposition of the split lateral rectus muscle (NTSLR) for treating strabismus from 3rd-nerve palsy. METHODS: An international, multicentre, registry of patients with unilateral 3rd-nerve palsy treated with NTSLR was created. Patients with concurrent surgery on the contralateral eye were excluded. Primary outcome was horizontal alignment within 15 prism dioptres (PD) of orthotropia. Incidence of technical difficulties and vision-threatening complications by 6 months post-procedure were reported. RESULTS: Ninety-eight patients met inclusion criteria. Median age was 33.5 years (IQR 10.75-46). Aetiologies included congenital (31%), neoplastic (16%) and traumatic (15%). Twenty-five per cent of patients had prior ipsilateral strabismus surgery. Median exotropia decreased from 70PD preoperatively (IQR 50-90) to 1PD postoperatively (IQR 0-15.5), with a success rate of 69%. Performing concurrent superior oblique muscle tenotomy (SOT) was independently associated with success (p=0.001). Technical challenges occurred in 30% of cases, independently associated with a history of ipsilateral strabismus surgery (p=0.01). Eleven per cent of patients had vision-threatening complications, independently associated with more posterior placement of the split lateral rectus (LR) muscle (p<0.001), and most commonly transient serous choroidal effusion. Surgical placement of the split LR muscle within 4.25 mm of the medial rectus (MR) muscle insertion reduced this risk. CONCLUSION: NTSLR significantly improved primary position alignment altered by 3rd-nerve palsy. Concurrent SOT and placement of the split LR muscle ≤4.25 mm posterior to the MR muscle insertion optimised outcomes. NTSLR proved technically challenging when prior ipsilateral strabismus surgery had been performed.
Bosque LE, Yamarino CR, Salcedo N, Schneier AJ, Gold RS, Blumenfeld LC, Hunter DG. Evaluation of the blinq vision scanner for detection of amblyopia and strabismus. J AAPOS 2021;Abstract
PURPOSE: To report the results of a clinical study designed to evaluate the accuracy of the blinq pediatric vision scanner, which detects amblyopia and strabismus directly by means of retinal polarization scanning, unlike other vision screening devices, which infer possible disease based on detection of refractive risk factors. METHODS: Subjects 1-20 years of age were prospectively enrolled in this cross-sectional diagnostic accuracy study with planned enrollment of 200. All enrolled subjects were tested by individuals masked to the diagnosis, followed by complete ophthalmologic examination by pediatric ophthalmologists masked to the screening result. Patients previously treated for amblyopia or strabismus were analyzed separately. RESULTS: The study cohort comprised 193 subjects, 53 of whom had been previously treated, leaving 140 treatment-naïve subjects, including 65 (46%) with amblyopia or strabismus, 11 (8%) with risk factors/suspected binocular vision deficit without amblyopia/strabismus, and 64 (46%) controls. Sensitivity was 100%, with all 66 patients with referral-warranted ocular disease referred. Five patients with intermittent strabismus receiving pass results were deemed "acceptable pass" when considering patient risk factors and amblyogenic potential. Specificity was 91%, with 7 incorrect referrals. Subanalysis of children aged 2-8 years (n = 92) provided similar results (sensitivity 100%; specificity 89%). CONCLUSIONS: In this study cohort, the blinq showed very high sensitivity and specificity for detecting referral-warranted amblyopia and strabismus. Implementation of the device in vision screening programs could lead to improved rates of disease detection and reduction in false referrals.
Whitman MC. Axonal Growth Abnormalities Underlying Ocular Cranial Nerve Disorders. Annu Rev Vis Sci 2021;7:827-850.Abstract
Abnormalities in cranial motor nerve development cause paralytic strabismus syndromes, collectively referred to as congenital cranial dysinnervation disorders, in which patients cannot fully move their eyes. These disorders can arise through one of two mechanisms: (a) defective motor neuron specification, usually by loss of a transcription factor necessary for brainstem patterning, or (b) axon growth and guidance abnormalities of the oculomotor, trochlear, and abducens nerves. This review focuses on our current understanding of axon guidance mechanisms in the cranial motor nerves and how disease-causing mutations disrupt axon targeting. Abnormalities of axon growth and guidance are often limited to a single nerve or subdivision, even when the causative gene is ubiquitously expressed. Additionally, when one nerve is absent, its normal target muscles attract other motor neurons. Study of these disorders highlights the complexities of axon guidance and how each population of neurons uses a unique but overlapping set of axon guidance pathways.
Binenbaum G, Chang MY, Heidary G, Morrison DG, Trivedi RH, Galvin JA, Pineles SL. Botulinum Toxin Injection for the Treatment of Strabismus: A Report by the American Academy of Ophthalmology. Ophthalmology 2021;128(12):1766-1776.Abstract
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.

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