Strabismus

Strabismus Publications

Yahalom C, Hunter DG, Dagi LR. Strategies for managing strabismus from oculomotor nerve palsy. J AAPOS 2023;Abstract
Addressing ocular misalignment secondary to partial and complete oculomotor nerve palsy presents a special challenge to the strabismus surgeon, particularly when treating patients with binocular diplopia. We review the reported surgical options and, through illustrative cases, provide our own perspective on managing this disorder.
Dohlman JC, Hunter DG, Heidary G. The Impact of Strabismus on Psychosocial Equity. Semin Ophthalmol 2023;38(1):52-56.Abstract
Strabismus, the condition of misaligned eyes, can result in severe, long-lasting functional and psychosocial sequelae. This review examines existing literature that has described and quantified the psychosocial consequences of strabismus. In particular, the role of strabismus in creating social, psychological, and vocational disparities, and how these intersect with race, ethnicity, and gender, is described. The reviewed data suggest that negative perceptions of strabismus are formed early in life. Overall, exotropia is more easily noticed than esotropia. Esotropia is perceived more negatively than exotropia, and there is significant variation with respect to gender, racial, and ethnic groups. The data demonstrate that the presence of strabismus affects self-esteem, interpersonal relationships, and access to vocational opportunities. Surgical correction of strabismus has been shown to provide significant and long-lasting improvements in psychosocial well-being.
Phanphruk W, Hennein L, Hunter DG. Strabismus surgery in orthophoric patients with symptomatic, asymmetric vertical or horizontal incomitance. Am J Ophthalmol 2022;Abstract
PURPOSE: To report the indications, operative strategies, and surgical outcomes of patients who undergo vertical and horizontal rectus muscle surgery for incomitant strabismus despite being orthophoric in primary gaze. DESIGN: Retrospective, interventional case series. METHODS: • Setting: Academic practice at Boston Children's Hospital. • Patient Population: Eight orthophoric patients who underwent strabismus surgery to treat vertical/horizontal incomitance. • Observation Procedures: Review of surgical strategies, strabismus measurements in diagnostic gaze positions, development of post-op diplopia. • Main Outcome Measures: Preserved single vision in primary gaze, comitance, reoperation rate, and patient/surgeon satisfaction. RESULTS: Surgical strategies included 1) simultaneous recession of ipsilateral antagonist rectus muscles; 2) recession or resection of one rectus muscle with balancing surgery on the fellow eye; 3) restricting range of one muscle (combined resection and recession or posterior fixation suture); 4) creating an acceptable deviation in primary gaze. Mean follow-up was 5.4 months (median, 2 months; range, 2-25). No patient had new-onset primary gaze diplopia. Median incomitance improved by 9.5 PD. No patient required additional surgery. Patient satisfaction and surgeon assessment of outcomes were high. CONCLUSIONS: Although the risk of operating on orthophoric patients with incomitant strabismus may discourage surgeons from offering treatment, the use of specific strategies to address incomitance can preserve alignment in primary gaze while improving patient satisfaction. These strategies may also benefit patients with incomitant strabismus that is symptomatic in primary gaze.
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, 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, Shah AS, Dagi LR, Dagi LR. Nasal Transposition of the Split Lateral Rectus Muscle for Strabismus Associated With Bilateral 3rd-Nerve Palsy. Am J Ophthalmol 2022;242:165-172.Abstract
PURPOSE: To determine the 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: An international, multicenter registry was used for the study. The study population was all patients with bilateral 3rd-nerve palsy treated with NTSLR. Sensorimotor evaluations were conducted before and 6 months after unilateral or bilateral NTSLR. Outcome measures were postoperative 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: A total of 34 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 postoperative exotropia of 18 PD (IQR = 7-35 PD), and when performed bilaterally (35%) resulted in postoperative exotropia of 14 PD (IQR = 5-35 PD). Success was achieved in 50% of cases, intraoperative technical difficulties were 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 (odds ratio = 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 may 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.

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