Strabismus Surgery In Patients Research Articles

Strabismus surgery for patients with acquired nonaccommodative esotropia based on monocular occlusion test

PurposeTo evaluate the outcome of surgery based on a monocular occlusion test in patients with acquired nonaccommodative esotropia (ANAET). MethodsPatients with ANAET in which the angle of esodeviation increased by at least 10Δ after 1 hour of monocular patching were enrolled prospectively. ResultsA monocular occlusion test was performed for 32 patients, of whom 14 patients showed significant change in the angle of esotropia. The mean age was 21.4 (range, 5-50) years, and 8 (57%) were females. The mean spherical equivalent was 0.24 D for right eyes and 0.35 D for left eyes. The mean angle of esotropia before occlusion was 9.9Δ ± 6.4Δ (range, 2Δ-20Δ) for distance and 13.8Δ ± 6.6Δ (range, 4.5Δ-25Δ) for near. The mean angle of esotropia after monocular occlusion was 22.3Δ ± 5.1Δ (range, 12Δ-30Δ) for distance and 24.6Δ ± 6.2Δ (range, 12Δ-32.5Δ) for near. Bimedial rectus muscle recession was performed for all the patients according to near esotropia after 1 hour of monocular occlusion. Patients were followed for 12 months. Final mean angle of esodeviation was 1.0Δ ± 2.2Δ (range, 0Δ-6Δ) for distance and 3.6Δ ± 3.2Δ (range, 0Δ-10Δ) for near. But for a single case, patients achieved alignment <8Δ of esodeviation after surgery. There was no report of diplopia or other complications postoperatively. ConclusionsThe findings advocate incorporating monocular occlusion into the preoperative assessment to determine the surgical target in ANAET patients.

The effects of refractive status on the outcomes of strabismus surgery in patients with esotropia

BackgroundThe success of the strabismus surgery can hinge on several factors. One of these factors is refractive condition like hyperopia or myopia. Our study seeks to evaluate the surgical outcomes in patients with esotropia and myopia.MethodsThis case-control study encompassed all surgical cases of esotropia at Torfe and Negah Hospital between 2016 and 2021, which satisfied our specified inclusion criteria. The initial variables from electronic medical records were collected, including demographic, clinical, and surgery-related factors. At the final follow-up appointment, the level of eye deviation, both at distance and near, was recorded. We considered the operation a “success” for patients with a post-surgery distance eye deviation of 10(Pd) or less. Patients with greater deviation were classified as surgery failure. Statistical analyses were executed using SPSS software (version 16.0), and a P-value less than 0.05 was considered significant.ResultsOf the 194 patients evaluated, 112 were incorporated into the study. Surgical failure was observed in 14.29% of myopic patients, 29.79% of hyperopic patients, and 31.82% of emmetropic patients. The myopia group displayed a 0.19 odd ratio for surgical failure compared to the combined hyperopia and emmetropia groups, not statistically significant (OR: 0.19, CI 95%: 0.03–1.02). Additionally, patients diagnosed with Lateral Rectus Under-action were found to be 6.85 times more likely to experience surgery failure(OR: 6.85, CI 95%: 1.52–30.94). An elevated risk of surgical failure was also identified in patients who underwent Inferior Oblique Weakening procedure, indicated by a 3.77-fold increase in the odds ratio for failure(OR: 3.77, CI 95%: 1.08–13.17).ConclusionIn our study, despite numerical disparities, there was no statistical difference among the success rates of all esotropia patients with different refractive errors. The patients with LRUA or IOOA showed lower success rates. Myopic patients had higher post-op overcorrection with lower reoperation rates compared to hyperopic or emmetropic patients.

The distribution characteristics of strabismus surgery types in a tertiary hospital in the Central Plains region during the COVID-19 epidemic

ObjectiveThis study aimed to analyze the distribution of different types of strabismus surgery in a tertiary hospital in Central China during the three-year period of the COVID-19 pandemic.MethodsA retrospective analysis was conducted on the clinical data of strabismus patients who underwent surgery and were admitted to the Department of Strabismus and Pediatric Ophthalmology at the First Affiliated Hospital of Zhengzhou University between January 2020 and December 2022.ResultsA total of 3939 strabismus surgery patients were collected, including 1357 in 2020, 1451 in 2021, and 1131 in 2022. The number of surgeries decreased significantly in February 2020, August 2021, and November and December 2022. Patients aged 0–6 years accounted for 37% of the total number of strabismus surgery patientsr. The majority (60%) of all strabismus surgery patients were diagnosed with exotropia, with intermittent exotropia accounting for the highest proportion (53%). There was no statistically significant difference in the proportion of intermittent exotropia and constant exotropia during the three-year period (χ2 = 2.642, P = 0.267 and χ2 = 3.012, P = 0.221, respectively). Among patients with intermittent exotropia, insufficient convergence type was the most common form of strabismus (accounting for over 70%). Non-accommodative esotropia accounted for more than 50% of all internal strabismus cases.ConclusionDuring the period from 2020 to 2022, the total number of strabismus surgeries in our hospital did not show significant fluctuations, but there was a noticeable decrease in the number of surgeries during months affected by the pandemic. Exotropia accounted for the highest proportion among strabismus surgery patients. Intermittent exotropia was the most common type among patients undergoing surgery for exotropia, and the most prevalent subtype was the insufficient convergence type. The age distribution of patients varied in different months, with a concentration of surgeries for strabismus patients in the 7–12 years old age group during the months of July and August each year.

Ocular Movement Disorder after Scleral Buckling Surgery in Patients with Retinal Detachment

Purpose: Binocular diplopia is a primary complication that may arise after scleral buckling surgery in patients with rhegmatogenous retinal detachment. This study examined the incidence of and risk factors for binocular diplopia after scleral buckling surgery; it also evaluated the rate of strabismus surgery success in patients with diplopia.Methods: Medical records of 417 patients who underwent scleral buckling surgery for rhegmatogenous retinal detachment at a single institution from January 2017 to June 2022 were retrospectively reviewed. Patients who experienced binocular diplopia for &gt; 6 months were included in the diplopia group.Results: After surgery, 22 patients (5.3%) developed binocular diplopia. There were no significant correlations of diplopia onset with buckle position (i.e., the affected muscle), cryophotocoagulation, subretinal fluid drainage, and the use of gas or oil injections. Prism therapy restored binocular single vision in three patients. Ten patients chose to undergo strabismus surgery, and one patient underwent encircling band removal. All strabismus surgery patients displayed adhesion between the buckle and extraocular muscle. After surgery, 60% of these patients regained binocular single vision.Conclusions: Clear risk factors leading to ocular movement disorders and diplopia after scleral buckling remain undefined. If diplopia persists despite prism-based conservative treatment, strabismus surgery may offer relief.

Long-term outcomes of single monocular resection-recession in adult sensory strabismus and factors affecting the postoperative drift.

The purpose of our study was to analyze the clinical characteristics and outcome of horizontal strabismus surgery in patients having sensory strabismus and to analyze the factors that affect the postoperative drift in these patients over a follow-up of three years. This was a retrospective case series. Patients aged ≥18 years, having low vision (visual acuity ≤20/60) in one eye, and undergoing horizontal strabismus surgery (standard recess-resect procedures) in the same eye were recruited. All patients were advised patching of the good eye six weeks prior and continued for six weeks post strabismus surgery. We excluded patients who had paralytic disorders, motility defects, or those with chronic systemic conditions. Patients with a minimum follow-up of three years were recruited. The study included 56 patients whose mean age was 22.9 ± 4.93 years. Exotropia (n = 38; 67.8%) was more common than esotropia (n = 18; 32.1%). Preoperative visual acuity was 1.1 ± 0.85 (range perception of light to 6/18p). The cause of low vision was amblyopia (n = 30; 53.5%) followed by trauma (n = 22; 39.2%). The mean preoperative distance deviation was 57.7 ± 15.5 PD in the primary position (range: 20-65 PD). The success rate of exotropia (78.9%) was more than esotropia (52.9%) at three years. Two patients with esotropia were overcorrected. All patients with exotropia showed an exotropic drift with time. The motor alignment after a single recession-resection procedure was satisfactory at the long-term in our cohort of sensory strabismus. The duration or extent of visual impairment had no relation to the postoperative outcome.

Refractive changes after strabismus surgery in patients with intermittent exotropia.

To evaluate the long-term refractive changes after horizontal muscle surgery in patients with intermittent exotropia and investigate the correlation between changes in the postoperative refractive error and clinical factors. We retrospectively reviewed the clinical data of patients aged < 15 years who underwent unilateral strabismus surgery (lateral rectus recession and medial rectus resection [RR, n = 47], lateral rectus recession and medial rectus plication [RP, n = 81], or lateral rectus recession [LRc, n = 68]). Preoperative and postoperative refractive errors up to four years after surgery were recorded. A mixed model was applied to compare the refractive error between the operated and fellow eyes and identify the factors associated with postoperative refractive changes. The mean age at surgery was 7.5±2.4years, and girls accounted for 56.1% of the study population. There was no significant difference in the change in the spherical equivalent of refractive error between both eyes throughout the postoperative period. In contrast, the operated eyes consistently and significantly showed higher cylindrical power in with-the-rule astigmatism by 0.25D than in fellow eyes. Age, sex, and preoperative refractive error were not correlated with changes in postoperative astigmatism. Meanwhile, the type of surgery showed a significant interaction with the astigmatism changes. RP had less effect on the changes in astigmatism than RR and LRc (p = 0.001 and p = 0.022, respectively). Horizontal muscle surgery has no long-term effect on the change in the spherical equivalent. However, mild with-the-rule astigmatism is induced and sustained after surgery, and the type of surgery affects the postoperative change of astigmatism.

Long-term surgical outcomes of unilateral horizontal muscle strabismus surgery in patients with sensory esotropia versus sensory exotropia

Long-term surgical outcomes of unilateral horizontal muscle strabismus surgery in patients with sensory esotropia versus sensory exotropia

Evaluation of aberrometry changes following strabismus surgery in patients with horizontal strabismus.

The aim is to investigate the change in aberrations following strabismus surgery in patients with horizontal strabismus. This prospective study included patients who underwent surgery for horizontal strabismus. The patients were assessed preoperatively and 1 month and 3 months after the surgery, in terms of logMAR best-corrected visual acuity, eye deviation, spherical equivalent refractive error, tomographic and aberrometric corneal changes. Corneal tomography was performed using Orbscan II device. Wavefront analyses were performed using Bausch and Lomb Zywave II. A total of 25 patients (48 eyes) with exotropia or esotropia were entered in this study. Mean values of exotropia in the distance and near deviations were reported as 31.42 ± 7.13 and 28.82 ± 6.96 prism diopters (PD), respectively. Mean scores of esotropia in the distance and near deviations were 25.22 ± 5.41 and 30.45 ± 9.4 PD, respectively. Evaluation of irregularity in 5 mm zone, horizontal coma, spherical aberration changes, and root mean square of higher-order aberrations (HOAs) in 6 mm, and HOA w/o Z 400 changes showed that there was a significant difference before the intervention and 1 month after the surgery (P < 0.05). However, no difference was observed in the aforementioned variables before and 3 months after the intervention (P > 0.05). Results of the present study indicated a transient increase in HOAs and corneal irregularity following strabismus surgery on horizontal eye muscles that returned to the baseline after 3 months.

Larger Than Larger: Huge Amounts of Recession-Resection Surgery for Third Nerve Palsy.

To describe the characteristics and management outcomes of strabismus surgery in patients with third cranial nerve palsy and identify factors associated with long-term outcomes. A 10-year retrospective study of patients with third cranial nerve palsy who underwent strabismus surgery was performed at Zhongshan Ophthalmic Center, Sun Yat-sen University, China, between August 2010 and January 2021. Clinical characteristics and factors associated with long-term outcomes were evaluated. Success of surgery was defined as esotropia of 15 prism diopters (PD) or less at postoperative day 1 (POD1) or any deviation of 10 PD or less at postoperative month 2 (POM2) or later. A total of 91 patients were included, with a mean age of 24.02 ± 15.38 years (range: 2 to 64 years). Forty-one patients (45.1%) were diagnosed as having complete palsy. Congenital palsy accounted for 40.7% (n = 37). Mean follow-up time was 2.50 ± 1.78 years (range: 8 months to 8 years). One-step surgery was performed in 78.0% of cases (n = 71), a staging procedure in 7.7% (n = 7), and reoperations in 14.3% (n = 13). Most patients had supra-maximal recession and resection of the horizontal rectus muscle with additional techniques, including horizontal rectus transposition, superior oblique transposition, traction sutures, and fixation of the globe. The mean surgical dosage performed on the horizontal rectus muscle was 18.52 ± 5.69 mm (range: 8 to 35 mm). Success rates at postoperative month 8 (POM8) were 69.0% (49 of 71) in the one-step surgery group, 57.1% (4 of 7) in the staging surgery group, and 46.2% (6 of 13) in the reoperation group. Preoperative horizontal deviation (odds ratio [OR]: 1.07, 95% CI: 1.02 to 1.13, P = .011), horizontal deviation at POD1 (OR: 0.86, 95% CI: 0.76 to 0.97, P = .016), and horizontal deviation at POM2 (OR: 1.53, 95% CI: 1.18 to 1.98, P = .001) were associated with the outcomes at POM8. Patients with partial palsy had a higher success rate than those with complete palsy (76.0% vs 51.2%, P = .014). Supra-maximal recession and resection with additional techniques yields satisfying surgical results in patients with third nerve palsy when a larger surgical dose is performed for an initial overcorrection for 15 to 25 PD at POD1. The cases with complete palsy showing a larger deviation were prone to failure. [J Pediatr Ophthalmol Strabismus. 2023;60(3):184-194.].

Sequential changes in intraocular pressure during strabismus surgery in patients with thyroid eye disease

Background/AimsTo investigate the sequential change in intraocular pressure (IOP) during strabismus surgery in patients with thyroid eye disease (TED).MethodsThis prospective study included patients with TED who underwent strabismus surgery (medial rectus [MR], inferior rectus [IR], and superior rectus [SR] recession) between March 2018 and December 2020. The IOP was measured six times during surgery (5 min after intubation, after isolation of the muscle using a hook and dissection of the surrounding tissue, immediately before muscle detachment, immediately after muscle detachment, after reattachment of the muscle, and after closure of the conjunctiva).ResultsThirty-five eyes of 18 patients were included. The mean IOP at first was 21.1 mmHg, which significantly increased to 28.6 mmHg after muscle isolation. The IOP significantly decreased to 15.5 mmHg after muscle detachment. This increased to 19.1 mmHg after muscle reattachment. The last IOP was 18.9 mmHg. There were similar patterns of sequential change in the IOP among the three muscles. The MR showed the highest increase in IOP. The IR showed the lowest mean IOP compared with the other two muscles.ConclusionsThe IOP was elevated during the isolation and dissection of the surrounding muscle tissue, especially in the MR. The IOP significantly decreased after muscle detachment and was maintained until the last measurement, even after muscle reattachment. IR showed the lowest IOP among the three muscles during surgery.

Outcomes and risk factors of surgical management of thyroid eye disease-related diplopia.

To evaluate the outcomes of strabismus surgery in patients with thyroid eye disease (TED) and to assess the influence of preceding treatments such as steroid administration, orbital decompression and radiotherapy. Retrospective study on a cohort of patients with TED undergoing strabismus surgery. Data collection included clinical features, smoking status, preceding steroid therapy, orbital radiation therapy and orbital decompression. Qualitative evaluation, assessing diplopia and quality of life and quantitative evaluation, assessing the eye misalignment were analysed 1 year after the last squint surgical procedure. Seventy-nine patients were identified. Ninety-five surgical procedures were performed on 92 eyes. A significant overall improvement of ocular motility was registered (p < 0.001, paired t-test). Forty-five (57%) patients had excellent outcomes, twenty-three (29%) had good outcomes and eleven (14%) had poor outcomes. The average number of muscles operated was significantly greater in patients who underwent orbital bone decompression (1.58 ± 0.63; p = 0.0082; 95% CI 1.413-10.214). Quantitative and qualitative outcomes were not associated with the preceding therapy: steroid (p = 0.75), radiotherapy (p = 0.95) or orbital bone decompression (p = 0.25). The success rate was no different between adjustable and fixed sutures (p = 0.8). Strabismus surgery in TED patients resulted in a high success rate in reducing diplopia and improving ocular motility. The success rate was not negatively associated with previous therapies. Indeed, resolution of diplopia required more squint procedures in patients who have previously undergone to orbital decompression.

Prism adaptation test before strabismus surgery in patients with decompensated esophoria and decompensated microesotropia

PurposeTo evaluate the effect of Prism adaptation test (PAT) on the angle of squint in decompensated esophoria (decEPH) and decompensated microesotropia (decMET).MethodsIn this single-center retrospective study we reviewed the medical records of patients with the diagnosis of decEPH or decMET, aged at least 12 years, who were treated by strabismus surgery for the first time. The maximum Angle of squint (AOS) for far (F) and near (N) fixation and PAT results before surgery, as well as AOS (F) and AOS (N) after surgery and results of binocular function tests were considered. PAT included wearing a prism based on the largest angle for over 60 min.Results100 patients (mean age 37 ± 17 years) were included in the decEPH group, 82 patients (mean age 30 ± 13 years) in the decMET group. For decEPH, before surgery AOS was 25.5 ± 8.8 pdpt (F) and 23.5 ± 9.8 pdpt (N). During PAT the AOS increased significantly by 2.7 ± 4.3 to 28.2 ± 8.6 pdpt (F) and by 4.9 ± 4.5 to 28.3 ± 9.5 pdpt (N). Altogether, in 82% of decEPH patients AOS (F) and/ or AOS (N) in- or decreased by at least 3 pdpt. For decMET, before surgery AOS was 28.6 ± 10.8 pdpt for far (F) and 30.9 ± 11.8 pdpt for near fixation (N). During PAT the AOS increased significantly by 4.2 ± 5.8 to 32.5 ± 9.5 pdpt (F) and by 3.7 ± 6.1 to 34.4 ± 9.5 pdpt (N). Altogether, in 51% of decMET patients, AOS (F) and/ or AOS (N) increased by at least 10 pdpt, therefore more than 5° which would have been maximally expected from mictrotropia, or decreased by at least 3 pdpt.ConclusionsThe Prism adaptation test (PAT) showed remarkable changes in AOS in both decEPH and decMET. In patients with decEPH, the preoperative assessment of the “true AOS” under PAT reflects a pivotal requirement for successful strabismus surgery, as 82% had dose relevant angle changes ≥ 3 pdpt. For patients with decMET the preoperative prism adaptation test is especially of diagnostic value, but also 51% of decMET patients had changes in AOS beyond the expected microtropic angle (≥ 10 pdpt) or even a dose relevant angle decrease (≥ 3pdpt).

Strabismus Repair in Children with Varying Severity of Cerebral Palsy

ABSTRACT Objective To study the success rate of strabismus surgery in patients with varying levels of severity of cerebral palsy (CP). Design A retrospective study was conducted. Participants Sixty-four patients with varying severity of CP were included. Methods All patients with different CP severity levels underwent strabismus surgery. Success was defined as any postoperative heterotropia outcome of less than 10 prism diopters in primary position. Statistical analysis was conducted using chi-square. Results The mean age at the time of strabismus surgery was 3.1 years, and the mean follow-up was 6.0 years. The most common types of strabismus were infantile-onset exotropia in 36 patients (56%) and infantile-onset esotropia in 28 patients (44%). Surgical success was found to be better in patients with mild GMFCS (GMFCS levels 1–2) with 68% having less than 10 PD of eso or exotropia in primary gaze, as compared to patients with severe GMFCS (GMFCS levels 3–5) (38% with 10 PD of heterotropia) (P < .05; χ2). Refractive errors included myopia (27.5% in mild cases and 41.6% in severe), emmetropia (10% in mild and 8.3% in severe) and hyperopia (62.5% in mild and 50% in severe). Around 50% of the mild cases had absent binocular fusion compared to 66.6% of those with severe CP. Amblyopia was found in 62.5% of the mild cases and 54.1% of the severe cases. Nystagmus was present in 25% with mild disease and 29.1% of those with severe disease. Conclusion Restoration of good ocular alignment in patients with CP is achievable in more than half of the cases. Patients with more severe CP have poorer outcomes than those with milder palsies. There appears to be no difference in outcomes between the different types of strabismus.

ADVANCES IN AUTISM GENETICS: FROM GENE DISCOVERY TO ASPECTS OF HETEROGENEITY

We describe a surgical technique to perform strabismus surgery in patients with a scleral buckle that allows for the use of adjustable sutures without removing or modifying the exoplant.

PSYCHEMERGE: A DEEP DIVE INTO THE WORLD OF EHR-BASED PSYCHIATRIC GENOMICS

We describe a surgical technique to perform strabismus surgery in patients with a scleral buckle that allows for the use of adjustable sutures without removing or modifying the exoplant.

POLYGENIC RISK OF COMORBID ANXIETY AND DEPRESSION ACROSS HEALTH SYSTEMS

We describe a surgical technique to perform strabismus surgery in patients with a scleral buckle that allows for the use of adjustable sutures without removing or modifying the exoplant.

BRINGING VALUE FROM CONSUMER GENETICS TO THE CLINIC

We describe a surgical technique to perform strabismus surgery in patients with a scleral buckle that allows for the use of adjustable sutures without removing or modifying the exoplant.

Strabismus surgery in poor binocular potential: Change in quality of life

Background: Previous studies prove improvement in quality of life (QOL) after strabismus surgery. Aims: The aim is to study the change in QOL and binocular functions after strabismus surgery in patients with poor binocular potential. Setting and Design: A tertiary care center-based prospective study was done over a period of 1 year to evaluate the change in scores of adult strabismus-20 (AS-20) questionnaire after successful strabismus surgery. Materials and Methods: All patients above 10 years attending the orthoptic clinic with horizontal squint were evaluated for their probability of gaining binocularity on binocular potential score and were graded into four categories. Those with poor grade of binocular potential, having a poor chance of regaining binocularity after surgery, were included in the study. They underwent surgical ocular alignment and answered the AS-20 questionnaire for QOL preoperatively and 3 months postoperatively. Statistical Analysis Used: Comparison of preoperative scores was done using unpaired t-test. The mean pre- and post-operative scores were compared using paired t-test. Two-sided significance level with P

Oculocardiac Reflex During ROP Exams.

PurposeReducing physiologic stress including bradycardia during staging eye exams for retinopathy of prematurity (ROP) is desirable. We observed heart rate change during routine retinopathy of prematurity eye examinations and compared the response with our ongoing study of oculocardiac reflex (OCR) elicited by uniform EOM tension during strabismus surgery.Patients and MethodsElectrocardiograph was prospectively monitored during ROP exams featuring indirect ophthalmoscopy with Alfonso lid speculum and see-through scleral depressor without topical anesthesia. Clinical data were retrieved from ROP-Check software. OCR was defined as maximally changed heart rate (HR) as a percent of baseline. Strabismus surgery patients under general anesthesia served as controls.ResultsFrom 10/2017 to 9/2020, 281 infants had ROP exams, and the median OCR was 55.9% of baseline HR (IQR 41.4% to 72.6%), the kurtosis 0.93 and skewness 1.01 representing a drop from HR 169 ± 16 bpm to 102 ± 39 bpm. In comparison, 1493 adult and pediatric strabismus surgery patients had less OCR median bradycardia 87.8% (IQR 72–98%), kurtosis 1.60 and skewness −1.18. ROP %OCR correlated with birth gestational age (%OCR = 2.5 (GA) – 11, r(279)=0.33, p<0.01) and with birthweight (%OCR = 0.02 (BW) + 38, r(279) =0.35, p<0.01). The duration of bradycardia induced by ROP exam averaged 92 ± 34 seconds (range 34–240 seconds).ConclusionBradycardia is common during eye exams in the smallest premature infants with greater degree, more rapid onset and longer duration than OCR during strabismus surgery.

Surgical treatment of strabismus in thyroid eye disease: characteristics, dose–response, and outcomes

To describe the surgical management, dose-response, and postoperative outcomes of strabismus surgery in patients with thyroid eye disease. The medical records of patients operated on between 2014 and 2018 were reviewed retrospectively. Patient characteristics and surgical data were collected. Motor success was defined as vertical deviation of ≤5Δ and horizontal deviation of ≤10Δ; sensory success, as no diplopia in primary gaze. A total of 76 patients (mean age, 62.2±12.9years; 50 females) underwent 87 surgeries, most commonly unilateral inferior rectus recession (unilateral IR, 48%) and bilateral medial rectus recession (bilateral MR, 23%). Motor success was achieved in 69% and sensory success in 58%. For unilateral IR surgery, the dose-responses were 3.25Δ/mm (SE=0.616; β=0.650; P<0.001) at distance and 2.48Δ/mm (SE=0.752; β=0.472; P=0.002) at near; for bilateral MR surgery, 3.93Δ/mm (SE=0.997; β=0.680; P=0.001) at distance and 5.05Δ/mm (SE=1.374; β=0.655; P=0.002) at near. Median (Q1, Q3) postoperative drift was toward overcorrection for both procedures (unilateral IR, -2Δ [-8, 0] at distance and -2Δ [-7, 0] at near; bilateral MR, -2Δ [-8, 2] at distance and -2Δ [-10, 0] at near). Sex, age, duration of strabismus, prior orbital decompression, and concurrent vertical and horizontal procedures were not associated with dose-response or postoperative drift. Concurrent vertical and horizontal surgery did not affect the motor success rate, dose-response, or postoperative drift. Although unilateral IR surgery had a larger dose-response at distance, bilateral MR surgery had a larger dose-response at near. Most procedures tended to have a postoperative drift toward overcorrection.