The changes in ocular torsion after unilateral lateral rectus recession-medial rectus resection for intermittent exotropia.

We aim to explore the alterations of objective ocular torsion after unilateral lateral rectus recession-medial rectus resection (R&R) for intermittent exotropia (IXT). Seventy-two IXT patients undergoing R&R between March and June 2023 were enrolled. Ophthalmological examinations were performed before surgery and at 1 week and 1 month after surgery, mainly including prism and alternate cover test and optical coherence tomography. The mean disc-foveal angle of eyes showing intorsion significantly increased from - 1.5 ± 0.9° preoperatively to 2.0 ± 2.0° at 1 week (P = 0.0227) and 2.2 ± 1.6° at 1 month postoperatively (P = 0.0054). The mean disc-foveal angle of eyes exhibiting extorsion significantly reduced from 12.8 ± 1.9° preoperatively to 9.8 ± 3.1° at 1 week (P < 0.0001) and 9.7 ± 2.7° at 1 month postoperatively (P < 0.0001). The improvement of ocular extorsion at postoperative 1 month was more pronounced in patients with extorsion in operative eye compared to those with extorsion in inoperative eye (P = 0.0101). The improvement of ocular torsion was observed following R&R for IXT, with a greater effect noted in cases where the surgery was performed on the eye exhibiting extorsion.

Experience with Strabologic Surgery on Pediatric Patients with Divergence Excess Exotropia.

AIM: This retrospective clinical study evaluates the results of surgical treatment of patients diagnosed with intermittent exotropia of the divergence excess type. The study compares the results of surgery delayed due to the Covid-19 pandemic (patients underwent the surgery after the age of eight), versus a group of younger children. MATERIALS AND METHODS: The objective angle of deviation and quality of binocular functions were examined. The follow-up period was six months after surgery. The patients were divided into two groups according to age: 4-7 years and 8-13 years. Each group included 20 patients. The second group comprised patients whose surgery was postponed due to restrictions on elective surgery during the ongoing pandemic. The surgery took place at the University Hospital in Pilsen. Angle of deviation and binocular functions were examined before surgery, postoperatively, and three and six months after surgery. Data were collected retrospectively and statistically processed. The main values were plotted in charts. RESULTS: Accordance between the angle of deviation before surgery in both groups was statistically demonstrated. During the six-month follow-up period, the median angle of deviation was statistically without proof of disparity between the groups. Six months after surgery, an objective angle of deviation within the limit ±5 degrees was achieved in 65% of patients from the first group and in 75% from the second group. Binocular vision before surgery was statistically without proof of difference between both groups. However the statistical processing demonstrated a difference between the two groups six months after the surgery. Better binocular functions were achieved by the younger children in the first group. CONCLUSION: The objective deviation angle was comparable in both study groups prior to surgery as well as six months after the surgery. The first group of younger patients attained a higher quality of binocular functions within the six-month follow-up period compared to children operated on after the age of eight. This claim was statistically verified.

The comparison of postoperative changes in subjective awareness of exodeviation between pediatric and adult patients with intermittent exotropia.

To evaluate pre- and postoperative changes in the subjective awareness of exodeviation in patients with intermittent exotropia and compare pediatric and adult patients. This retrospective study included pediatric (6-17 years) and adult patients (≥18 years) with intermittent exotropia who underwent surgery. Patients with subjective awareness of exodeviation associated with exotropia were included. Postoperative improvement was defined as a decrease in the subjective awareness of exodeviation and alleviation of associated symptoms after surgery. Changes in subjective awareness of exodeviation after surgery were evaluated and compared between pediatric and adult patients. Clinical factors associated with postoperative improvement in subjective awareness of exodeviation were analyzed. A total of 195 patients (159 pediatric and 36 adult) were included. Among the included patients, 145 (74.4%, 145/195) reported postoperative improvements in their subjective awareness of exodeviation. A lower percentage of adult patients (15/36, 41.7%) showed postoperative improvement in subjective awareness of exodeviation than that of pediatric patients (130/159, 81.8%, P < .001). The level of distant control was significantly associated with postoperative improvement in subjective awareness of exodeviation in adult patients (odds ratio, 1.151; 95% confidence interval, 0.030-0.758; P = .022). There was a significant difference in the postoperative change in the subjective awareness of exodeviation between pediatric and adult patients with intermittent exotropia. Adult patients are less likely to exhibit postoperative improvement in subjective awareness of exodeviation than pediatric patients. Adult patients with a better level of distant control are more likely to show postoperative improvement in their subjective awareness of exodeviation.

Long-term surgical outcomes of one-muscle vs. two-muscle horizontal strabismus surgery.

PURPOSE: While horizontal strabismus surgery is generally considered to have favorable outcomes, success rates can vary by type of procedure. Our purpose is to compare the long-term outcomes of patients who underwent one-muscle vs. two-muscle horizontal strabismus surgery. METHODS: This is a retrospective study comparing one-muscle to two-muscle strabismus surgery for small to moderate angle horizontal strabismus. Demographic data and eye exam parameters were compared at baseline and postoperatively (6 months up to 6 years). Surgical success was defined as a post-operative angle of 10 PD or less. We also compared outcomes by strabismus type: esotropia vs exotropia and adjusted the analysis for previous strabismus surgery. RESULTS: Out of 89 patients with moderate angle horizontal strabismus (25 PD or less), 17 patients had a one-muscle operation, and 72 patients had two-muscle surgery. The mean age was 14.12 ± 9.30 years and 11.70 ± 11.30 years for the one-muscle and two-muscle groups, respectively (p = .74). The baseline characteristics of both groups were comparable. Follow-up time was 32.82 ± 26.93 months in one-muscle and 37.67 ± 23.81 in two-muscle groups (p = .29). Success rate was 70.6% for the one-muscle group and 68.10% for the two-muscle group (p = .69). Outcomes were similar when divided into esotropia and exotropia. The success rate was not affected by previous strabismus surgeries nor by the initial angle of deviation. CONCLUSION: One-muscle and two-muscle horizontal strabismus surgery had similar long-term outcomes and did not differ by strabismus type nor by angle of deviation.

Aberrant regeneration of accommodation in pediatric inferior division oculomotor palsy.

Aberrant regeneration occurs in forms of oculomotor motor nerve palsy and frequently involves the pupil, but the incidence and functional impact of ciliary muscle involvement in pediatric patients is sparsely reported in the literature. A 4-year-old girl presented with inflammatory oculomotor motor nerve paresis affecting the inferior division. Initial treatment focused on her inability to accommodate through her physiologic +2.5 D hyperopia and the prevention and treatment of amblyopia. She subsequently developed aberrant regeneration of the pupil, with miosis on adduction. Following eye muscle surgery for residual exotropia and hypertropia, her dry refraction was noted to be more myopic in the affected eye on adduction, mirroring aberrant pupillary constriction. Recognition of pediatric aberrant regeneration of accommodation may influence surgical planning for oculomotor nerve palsy and/or management of amblyopia.

Sensory exotropia versus sensory esotropia: A comparative clinical features study.

PURPOSE: This study aimed to compare the preoperative clinical features of patients with sensory esotropia (ET) and sensory exotropia (XT). METHODS: In a retrospective study, the medical records of 13,252 patients who underwent strabismus surgery were reviewed at the Farabi Eye Hospital, Iran, from 2012 to March 2022. There were 1017 patients with sensory horizontal strabismus whose, in their worse eye, had corrected distance visual acuity (CDVA) equal to or <20/160 tested with the Snellen chart. RESULTS: The mean age of patients was 29.0 ± 12.4 years [574 (56.4%) males and 443 (43.6%) females]. Sensory XT and ET were observed in 717 (70.5%) and 300 (29.5%) patients, respectively (P<.001). The mean CDVA in the strabismic and non-strabismic eyes was 1.40 ± 0.75 and 0.05 ± 0.13, respectively (P<.001). Also, the CDVA in the strabismic eyes was significantly worse in the patients with sensory XT than in the patients with sensory ET (P<.001). Sphere and spherical equivalent (SE) components were more hyperopic in both eyes of patients with sensory ET than sensory XT (P<.001). In sensory ET group, the mean horizontal deviation at far and near was significantly higher than the sensory XT group (both P<.001). The prevalence of moderate and severe amblyopia among all patients with sensory strabismus was 274 (26.9%) and 727 (71.5%), respectively (P<.001). There were 398 (39.1%) patients who needed more than one surgery. CONCLUSION: The frequency of sensory XT was about 2.5 times more than the sensory ET. Most patients with sensory ET were operated at a younger age, had better CDVA, more hyperopic spherical and SE, and higher angle of deviation compared with patients with sensory XT. The chance of reoperation in patients with sensory strabismus was about 40%.

Self-Reported Findings of the Korean Intermittent Exotropia Multicenter Study Questionnaire.

PURPOSE: To determine subjective symptoms and medical history of patients with intermittent exotropia in a large study population. METHODS: The Korean Intermittent Exotropia Multicenter Study (KIEMS) is a nationwide, observational, cross-sectional, multicenter study conducted by the Korean Association for Pediatric Ophthalmology and Strabismus including 5,385 patients with intermittent exotropia. Subjective symptoms and medical history of patients with intermittent exotropia were extracted by a comprehensive survey based on a self-administered questionnaire according to the study protocol of the KIEMS. RESULTS: The mean age of symptom onset was 5.5 years. The most common symptom reported in patients with intermittent exotropia was photophobia (52.1%), followed by diplopia at near fixation (7.3%) and distance fixation (6.2%). Preterm birth was found in 8.8%, and 4.1% had perinatal complications. A family history of strabismus was present in 14.9%, and 5.5% of patients had a family member who underwent strabismus surgery. CONCLUSIONS: The KIEMS is one of the largest clinical studies on intermittent exotropia. Intermittent exotropia frequently caused photophobia and diplopia, and patients with a family history was not uncommon.

Parental perspectives and concerns regarding exotropia surgery and comparison with clinicians' predictions.

PURPOSE: To evaluate parental perspectives and concerns regarding exotropia surgery and compare them with clinicians' predictions of parental responses in Korean pediatric patients with intermittent exotropia. METHODS: This survey study included the parents of pediatric patients with intermittent exotropia who underwent surgery and clinicians at five hospitals from June 2022 to February 2023, who participated in the Survey of Parental Attitude and Concerns of Exotropia surgery (SPACE) study 1. Parental attitudes and concern about exotropia surgery were assessed using a questionnaire. Clinicians' estimation of each item corresponding to the parental questionnaire was also assessed and compared with parental responses. RESULTS: A total of 266 parents and 41 clinicians were included. More parents responded that information about surgery was most helpful or most commonly received from clinicians than clinicians estimated (P = 0.001). More parents reported actively communicating with the child about surgery than clinicians estimated (P < 0.001). Parents showed a higher level of concern for general anesthesia and the hospital environment than clinicians thought they would (P = 0.002 and P < 0.001, resp.). In the postoperative follow-up items, parents showed high levels of concern regarding postoperative infection (P < 0.001), conjunctival redness (P = 0.040), persistent overcorrection (P < 0.001), and glasses wearing (P = 0.019). CONCLUSIONS: Parental perspectives and concerns regarding pediatric intermittent exotropia surgery differed from clinicians' estimations thereof. More parents obtain information on exotropia surgery from clinicians and actively talk about surgery with their child than estimated by clinicians. Parents had a higher level of concern regarding general anesthesia, hospital environment, postoperative infection, conjunctival redness, persistent overcorrection, and glasses wearing compared with clinician estimations.

Surgical management of oculomotor nerve palsy: a comparison of lateral rectus deactivation combined with either medial rectus resection or medial rectus fixation to the medial palpebral ligament.

PURPOSE: To analyze and compare the outcome of two different surgical procedures in patients with complete oculomotor nerve palsy with large-angle exotropia. METHODS: The medical records of patients with total oculomotor nerve palsy and large-angle exotropia operated on at a single center from January 2006 to June 2020 were reviewed retrospectively. One group underwent lateral rectus deactivation with medial rectus resection (resection group); the other group underwent lateral rectus deactivation with medial rectus fixation to the medial palpebral ligament (fixation group). Surgical outcomes on the first postoperative day and at 6 months postoperatively were analyzed, including alignment and postoperative complications. All statistical analyses were performed using STATA version 14. A P value of <0.05 was considered significant. RESULTS: A total of 35 patients were included. There was a trend toward greater surgical success in the fixation group (93%) than in the resection group (65%), but these results were not statistically significant. Postoperative exotropic drifts were noted in both the procedures but tended to be more with patients in the resection group. Postoperative complications were noted only in the fixation group. CONCLUSIONS: Lateral rectus deactivation with medial rectus fixation to the medial palpebral ligament requires more time and greater surgical expertise but appears to better prevent postoperative exotropic drift compared with lateral rectus deactivation combined with medial rectus resection.

Six-month binocular stereopsis recovery and its influencing factors in children with intermittent exotropia.

OBJECTIVE: To investigate the recovery of binocular stereopsis recovery and its influencing factors in children with intermittent exotropia after successful correction of eye position. METHODS: Prospective clinical study. A total of 178 patients, aged 9 ∼ 14 (10.8 ± 1.7) years, who were successfully corrected after intermittent exotropia surgery at the Beijing Tongren Hospital Affiliated to Capital Medical University from October 2023 to September 2023 were collected, the follow-up duration was six-month or longer. Paired t test, Pearson correlation analysis and multivariable linear regression analysis were used to probe preoperative clinical features that may predict the stereopsis six months after surgery. RESULTS: Six months after surgery, the angle of deviation of the patients met the orthotopic standard, and there was significant difference compared with that before surgery (distant: -2.7△±3.2△ vs. -30.5△±8.4△, t=-25.3, P < 0.001. Near:-3.7△±4.1△ vs. -33.7△±8.0△, t=-26.1, P < 0.001). Distant stereopsis (3.0 ± 0.6 vs. 3.9 ± 0.4, t = 4.9, P < 0.05) and near stereopsis (2.3 ± 0.5 vs. 2.6 ± 0.4, t = 3.8, P < 0.05) were both significantly improved compared with that of before surgery. 17% and 22% patients rebuilt normal distant stereopsis and normal near stereopsis, respectively. Preoperative distant stereopsis (r=-0.26, P = 0.004) and near stereopsis (r=-0.23, P = 0.011) was significantly negatively correlated with convergence reserve. Multivariable analysis showed that patients' age (ß = 0.003, p = 0.037), anisometropia (ß = 0.015, p = 0.043), and preoperative distant stereopsis (ß = 0.456, p < 0.001) were significantly associated with postoperative distant stereopsis. Patients' age (ß = 0.005, p = 0.044), anisometropia (ß = 0.127, p = 0.034), angle of deviation (ß=-0.230, p = 0.020), and preoperative near stereopsis (ß = 0.136, p < 0.001) were significantly associated with postoperative near stereopsis. CONCLUSION: IXT patients could get eye position fixed after surgery, about 20% patients benefited from stereopsis improvement. Patient's age, binocular anisometropia, angle of deviation and preoperative stereopsis were independent factors influencing postoperative stereopsis.

Strabismus management in retinoblastoma survivors.

PURPOSE: To report the result of strabismus surgery in eye-salvaged retinoblastoma (Rb) patients. METHODS: A retrospective case series including 18 patients with Rb and strabismus who underwent strabismus surgery after completing tumor treatment by a single pediatric ophthalmologist. RESULTS: A total of 18 patients (10 females and 8 males) were included with a mean age of 13.3 ± 3.0 (range, 2-39) months at the time tumor presentation and 6.0 ± 1.5 (range, 4-9) years at the time of strabismus surgery. Ten (56%) patients had unilateral and 8(44%) had bilateral involvement and the most common worse eye tumor's group was D (n = 11), C (n = 4), B (n = 2) and E (n = 1). Macula was involved by the tumors in 12 (67%) patients. The tumors were managed by intravenous chemotherapy (n = 8, 47%), intra-arterial chemotherapy (n = 7, 41%) and both (n = 3, 17%). After complete treatment, the average time to strabismus surgery was 29.9 ± 20.5 (range, 12-84) months. Except for one, visual acuity was equal or less than 1.0 logMAR (≤ 20/200) in the affected eye. Seven (39%) patients had exotropia, 11(61%) had esotropia (P = 0.346) and vertical deviation was found in 8 (48%) cases. The angle of deviation was 42.0 ± 10.4 (range, 30-60) prism diopter (PD) for esotropic and 35.7 ± 7.9 (range, 25-50) PD for exotropic patients (P = 0.32) that after surgery significantly decreased to 8.5 ± 5.3 PD in esotropic cases and 5.9 ± 6.7 PD in exotropic cases (P < 0.001). The mean follow-up after surgery was 15.2 ± 2.0 (range, 10-24) months, in which, 3 (17%) patients needed a second surgery. CONCLUSION: Strabismus surgery in treated Rb is safe and results of the surgeries are acceptable and close to the general population. There was not associated with tumor recurrence or metastasis.

Combined recession and resection of the same lateral Rectus in the treatment of exotropia.

BACKGROUND: Besides rest position abnormalities, exotropia could also be due to hypertonia of the Lateral Recti (LR) given divergence frequently decreases under general anesthesia (GA). Combined Recession-Resection of the Same Muscle (RRSM) is a promising alternative to the Faden procedure in the surgical treatment of overacting MR in esotropia. We thus examined here the effectiveness of combined RRSM of the LR for the treatment of exotropia that decrease under GA. METHODS: We performed a retrospective, single-center evaluation over a 16-month period of 100 patients operated on for exotropia that decreased under deep GA (91% of 110 consecutive operated cases). We excluded re-operations and pure convergence insufficiencies. We performed a combined RRSM of one or two LR. It included a 10mm-recession and a "fine-tuned" resection of LR based on Quantitative Forced Duction Test scores. MR resection was combined when exotropia exceeded 35PD or for unilateral surgery. We report on patient outcomes 6 months after surgery. RESULTS: Successful results were obtained (-8-+8 PD measured on Alternate Cover Test) among 83% of cases at distance fixation and 91% at near fixation after 6 months. The Newcastle Control Score also improved from 5.8 to 1.7 after 6 months. No surgery-related complications or repeat surgeries were reported. CONCLUSIONS: In our experience a majority of exotropias decrease under GA and our strategy of combined RRSM of the LR is effective for the treatment of such exotropias. Long-term follow-up of the cohort is required to investigate the stability of these outcomes, and confirmation of our results by other works.

Changes in ocular extorsion after horizontal muscle surgery in patients with intermittent exotropia coexisting with hypertropia and mild inferior oblique overaction.

PURPOSE: To investigate changes in vertical strabismus and extorsion in patients with intermittent exotropia and mild unilateral inferior oblique muscle overaction (IOOA) who underwent horizontal muscle surgery without vertical or oblique muscle surgery. METHODS: The medical records of 41 patients were retrospectively analyzed. The patients were followed up for at least 6 months after surgery. Fundus photography was performed before and after surgery, and the sum of the angles of torsion in both eyes was used to measure changes in extorsion using ImageJ software. The enrolled patients were divided into two groups according to the degree of IOOA: patients with grade 1 IOOA were placed in +1 IOOA group and those with grade 2 IOOA in +2 IOOA group. The pre- and postoperative angles of horizontal and vertical strabismus and extorsion were compared between the two groups. RESULTS: The +1 IOOA and +2 IOOA groups included 24 and 17 patients, respectively. The angle of preoperative exotropia did not differ significantly: 25.54 ± 5.68 prism diopters (PD) and 25.65 ± 8.11 PD in the +1 IOOA and +2 IOOA groups, respectively. In the +1 IOOA and +2 IOOA groups, hypertropia was 2.67 ± 1.52 PD and 2.82 ± 1.13 PD, respectively, and extorsion angles were 7.14 ± 2.77° and 7.94 ± 2.87°, respectively. As the IOOA degree increased, the extent of hypertropia and extorsion also increased. However, there were no significant differences between the two groups. Postoperative angles of hypertropia and extorsion significantly decreased in both groups (p < 0.001) after surgery. The degree of change in hypertropia and extorsion was not significantly different between the two groups (p = 0.563 and p = 0.354, respectively). CONCLUSIONS: Hypertropia and extorsion improved significantly after horizontal muscle surgery in patients with mild unilateral IOOA and intermittent exotropia. There was no significant difference in the improvement in hypertropia or extorsion between IOOA grades I and II.

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

OBJECTIVE: This 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. METHODS: A 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. RESULTS: A 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. CONCLUSION: During 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.

Medial Rectus Inferior Half Plication for the Treatment of Near Exotropia.

PURPOSE: To report a relatively new surgical treatment for near exotropia called medial rectus inferior half plication. METHODS: This was a retrospective analysis of the outcomes from a single surgeon performing a plication of the inferior half of the medial rectus muscle in 17 consecutive patients with near exotropia unresponsive to medial rectus bupivacaine injection. RESULTS: Thirteen of 17 (76%) patients were asymptomatic after surgery with no diplopia for near fixation and with either a normal or slightly reduced prism fusion range enabling them to have comfortable binocular single vision. There was one minor surgical overcorrection with distance diplopia that disappeared within 2 weeks of surgery. Of the 4 of 17 (24%) patients who required further intervention, 3 required one further surgical procedure and 1 required an injection of bupivacaine into the contralateral medial rectus muscle to obtain a satisfactory alignment and control of symptoms. No patient needed more than two total operations. CONCLUSIONS: The data show medial rectus inferior plication can produce excellent outcomes with minimal risk of overcorrection. [J Pediatr Ophthalmol Strabismus. 2024;61(3):219-222.].

Outcomes for maximal bilateral lateral rectus recession in large-angle exotropia.

BACKGROUND: Surgical treatment for large-angle exotropia can be challenging. The aim of this study was to evaluate short-term surgical outcomes of patients with large-angle exotropia (≥50Δ) undergoing maximal bilateral lateral rectus muscle recession of 10 mm. METHODS: This was a retrospective study of consecutive patients at our institution who underwent maximal bilateral lateral rectus muscle recession for exodeviation ≥50Δ from January 1, 2008, to July 22, 2022. We subdivided the cohort into large-angle exotropia (largest amount of exodeviation at near and/or distance ≥50Δ and <65Δ) and very large-angle exotropia (largest exodeviation ≥65Δ). Patients with a history of prior eye muscle surgery, neurologic deficits, and three- or four-muscle surgery were excluded. RESULTS: A total of 22 patients were included. Mean preoperative exodeviation at distance was 51.9Δ in the large-angle group and 67.5Δ in the very-large-angle group (P = 0.001). Outcomes for the large-angle and very-large angle groups were, respectively, as follows: mean follow-up, 31.1 weeks and 11.8 weeks (P = 0.97); success, 75.0% and 16.7% (P = 0.02); undercorrection rates, 18.7% and 83.3% (P = 0.01); and mean postoperative exodeviation at distance, 3.7Δ ± 6.3Δ and 28.0Δ ± 13.5Δ (P = 0.001). CONCLUSIONS: Our study identified good surgical outcomes (75%) with maximal bilateral lateral rectus muscle recession of 10 mm in treating patients with large-angle exotropia between 50Δ and <65Δ. Other surgical techniques such as recession-resection and three- or four-muscle surgery may result in better outcomes when treating patients with exotropia ≥65Δ.

Binocular Summation With Quantitative Contrast Sensitivity Function: A Novel Parameter to Evaluate Binocular Function in Intermittent Exotropia.

Purpose: Intermittent exotropia (IXT) is the most common form of strabismus. Surgery can potentially improve binocular function in patients with IXT. We aimed to evaluate binocular function using a novel parameter-binocular summation ratio (BSR), measured using quantitative contrast sensitivity function (CSF) in patients with IXT before and after surgery. Methods: Prospective study of 63 patients with IXT and 41 healthy controls were consecutively enrolled and underwent quantitative CSF testing binocularly and monocularly. BSR was calculated by dividing the CSF of the binocular value by the better monocular value. Forty-eight patients with IXT underwent strabismus surgery. BSR, stereoacuity, fusion ability, and strabismus questionnaires were assessed pre-operatively and 2 months postoperatively. Results: Sixty-three patients with IXT (median age = 9 years) compared with 41 healthy controls showed a worse mean BSR based on all CSF metrics at baseline (the area under the log CSF [AULCSF], spatial frequency [SF] cutoff, and contrast sensitivity at 1.0-18.0 cpd SF). All 48 patients with IXT showed successful alignment after surgery, and there were significant improvements in BSR based on the AULCSF, SF cutoff, and contrast sensitivity at 6.0, 12.0, and 18.0 cpd SF, respectively. The distance stereoacuity and fusion ability also improved after surgery, and a better BSR was associated with better stereoacuity and fusion. For strabismus questionnaires, the psychosocial subscale scores improved postoperatively, whereas the functional subscale scores did not change. Conclusions: BSR based on quantitative CSF can characterize binocular function across a range of spatial frequencies and can be used as a supplemental measurement for monitoring binocularity in patients with IXT in clinical settings.

Inferior displacement of the lateral rectus muscle insertion in exotropia with mild V-pattern or vertical deviation.

BACKGROUND: To describe clinical features and intraoperative findings of the patients with exotropia who presented mild V-pattern or vertical deviation, and to investigate the surgical outcomes of anatomical relocation of inferiorly displaced lateral rectus (LR) muscle insertion. METHODS: Detailed ophthalmological evaluations were obtained in 42 consecutive patients, and the horizontal rectus muscle insertions were detected intraoperatively. The displaced insertion of LR muscle was corrected accompanied with classic recession-resection procedure. RESULTS: The inferiorly displaced LR muscle insertions were detected in 19 patients (Group A), while the remaining 23 patients (Group B) had normal insertions. The mean distance of displaced insertion from the normal position was 2.92 ± 1.05 mm (range: 1.0-4.0). Mild V-pattern was more common in Group A (78.9%, 15/19) than Group B (47.8%, 11/23), and the magnitude of V-pattern in Group A (6.16 ± 3.91 PD) was also greater than Group B (3.43 ± 3.92 PD). The fundus extorsions of the affected eyes (9.68 ± 4.77 °) were greater than the contralateral eyes (5.91 ± 5.82 °) in Group A. At the 2 months follow-up, mild V-pattern and mild vertical deviation were corrected by upward transposition. The significant correlations were identified between the pre-operative misalignments and the amounts of misalignments correction. CONCLUSIONS: Nearly half of the cases with mild V-pattern or vertical deviation resulted from the inferiorly displaced LR muscle insertion, so the intraoperative exploration of the LR muscle insertion is strongly suggested. Upward transposition may effectively correct both the mild V-pattern and vertical deviation.

Analysis of postoperative exodrift according to surgical methods for intermittent exotropia.

PURPOSE: This study aimed to compare the periods for exodrift stabilization and the long-term surgical outcomes among different surgical methods in intermittent exotropia. METHODS: The medical records of 350 patients who had undergone intermittent exotropia correcting surgery [unilateral lateral rectus recession-medial rectus resection (R&R, n = 221), bilateral lateral rectus recession (BLR, n = 51) and unilateral lateral rectus recession (ULR, n = 78)] with a postoperative follow-up period of 1.5 years or more were retrospectively reviewed. The deviation angles every 6 months after surgery, periods of exodrift stabilization and surgical outcomes were analysed. The period of postoperative exodrift stabilization was defined as when exodrift was no longer significantly different from that at the next visit (p > 0.05). An alignment of 5 PD (prism diopters) esotropia to 10 PD exotropia at a distance and near fixation was considered surgical success. RESULTS: The mean angle of exodeviation was significantly different among surgical procedures at postoperative 1 month (BLR > ULR > R&R, p < 0.001); however, there were no differences among the procedures at 6 months (p = 0.088). The periods of exodrift stabilization were 6 months after ULR, 1 year after BLR and 4.5 years after R&R. The surgical success and reoperation rates did not show significant differences among procedures at the final follow-up. CONCLUSION: Patients undergoing R&R showed smaller exodeviation shortly after surgery but required a longer period to stabilize the exodrift. Following ULR, exodeviation was larger in the early postoperative period, but the exodrift was stabilized earlier. Therefore, the long-term surgical outcomes were similar among ULR, BLR and R&R.

Eight-Year Outcomes of Bilateral Lateral Rectus Recessions versus Unilateral Recession-Resection in Childhood Basic-Type Intermittent Exotropia.

PURPOSE: To report 8-year outcomes from a randomized controlled trial (RCT) comparing bilateral lateral rectus muscle recession (BLRc) with unilateral recession-resection (R&R) for childhood intermittent exotropia (IXT). DESIGN: Eight-year follow-up of RCT cohort. PARTICIPANTS: Of 197 randomized participants, 123 agreed to continue follow-up after the 3-year outcome visit (baseline age, 3-< 11 years; basic-type IXT, 15-40 prism diopters [Δ] by prism and alternate cover test [PACT]; baseline stereoacuity, ≤ 400 arcsec; no prior surgery). METHODS: After the RCT primary outcome at 3 years, annual follow-up from 4 through 8 years with treatment at investigator discretion. MAIN OUTCOME MEASURES: Suboptimal surgical outcome by 8 years after randomization, defined as any of the following at any visit: exotropia of 10 Δ or more by simultaneous prism cover test (SPCT) at distance or near, constant esotropia (ET) of 6 Δ or more by SPCT at distance or near, loss of near stereoacuity by 0.6 log arcsec or more from baseline, or reoperation. Secondary outcomes included (1) reoperation by 8 years and (2) complete or near-complete resolution at 8 years, defined as exodeviation of less than 10 Δ by SPCT and PACT at distance and near and 10 Δ or more reduction from baseline by PACT at distance and near, ET of less than 6 Δ at distance and near, no decrease in stereoacuity by 0.6 log arcsec or more from baseline, and no reoperation or nonsurgical treatment for IXT. RESULTS: The Kaplan-Meier cumulative probability of suboptimal surgical outcome through 8 years was 68% (55 events among 101 at risk) for BLRc and 53% (42 events among 96 at risk) for R&R (difference, 15%; 95% confidence interval [CI], -2% to 32%; P = 0.08). Complete or near-complete resolution at 8 years occurred in 15% (7/46) for BLRc and 37% (16/43) for R&R (difference, -22%; 95% CI, -44% to -0.1%; P = 0.049). The cumulative probability of reoperation was 30% for BLRc and 11% for R&R (difference, 19%; 95% CI, 2%-36%; P = 0.049). CONCLUSIONS: Despite no significant difference for the primary outcome, the 95% CI did not exclude a moderate benefit of R&R, which together with secondary outcomes suggests that unilateral R&R followed by usual care may yield better long-term outcomes than BLRc followed by usual care for basic-type childhood IXT using these surgical doses. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.