Exotropic Patients Research Articles

Multiple factors causing variability of alignment in childhood concomitant strabismus

Purpose: To investigate the potential factors related to variability of alignment in childhood concomitant strabismus. Design: Prospective inter-examiner (test-retest) reliability analysis. Methods: In total, 197 children with concomitant strabismus (57 esotropia, 140 exotropia) underwent repeat prism and alternate cover test (PACT) by two orthoptists who were certified by the study, and sensory tests were all performed once. We defined the alignment measurement as stable if the absolute value of the measurement difference between two orthoptists was within 10 prism diopters (PD), and unstable if the difference was 10 PD or greater. We analyzed the relationship between the measurement variability and sensory results, patient age, and angle of deviations. Results: The mean age of the esotropia and exotropia patients was 68.5 ± 26.3 months (range, 36–164 months) and 96.0 ± 33.7 months (range, 22–200 months), respectively, and there was a significant difference in suppression related variability of alignment, both at distance (P = 0.004) and at near (P = 0.046). Anisometropia also showed a significant difference at distance (P = 0.035) for variability of alignment, and there was no significant statistical effect of age on measurement variability in our study. Variability of alignment is positively associated with the angle of deviation, especially at distance (P = 0.021 for exotropia, P = 0.002 for esotropia) with more variability between observers with larger angles of misalignment. Conclusion: Suppression is an important factor for variability of alignment in childhood concomitant strabismus. Other factors, such as anisometropia and a large angle of strabismus should be taken into account when evaluating binocular alignment.

Medial rectus insertion site in cases of acute acquired comitant esotropia associated with excessive digital device usage.

To compare the distance of the medial rectus muscle insertion to the limbus (DMIL) between patients with acute acquired comitant esotropia (AACE) associated with excessive digital device usage (EDDU) and exotropic patients. Retrospective study. The medical records of 72 eyes of 44 patients with EDDU were retrospectively analyzed. The DMIL was measured from the anterior part at the midpoint of the medial rectus muscle insertion into the anterior limbus using a caliper after dissecting the medial rectus muscle with two control sutures at 12 o'clock and 6 o'clock. The DMIL in the non-fixation eye was compared between 44 patients with AACE and 23 patients with exotropia. The mean daily EDDU was 6.5 ± 3.1h. The mean cycloplegic refractive errors (spherical equivalent: SE) were - 3.18 ± 2.52 diopters (D) OD and - 3.03 ± 2.42 D OS. The mean DMIL in the 72 eyes of 44 patients with AACE associated with EDDU was 4.30 ± 0.66mm. The difference in DMIL of non-fixation eyes between 44 AACE patients and 23 exotropic patients was significant (4.28 ± 0.65mm vs. 5.28 ± 0.50mm, p < 0.0001). However, the SE in 44 non-dominant eyes of AACE was - 3.08 ± 2.56 D, significantly stronger than - 1.22 ± 1.93 D in the 23 exotropic eyes (p = 0.008). DMIL in patients with AACE associated with EDDU was significantly shorter. This anatomical anomaly may be an etiology of AACE associated with EDDU.

Association of Accommodation and Convergence with Axial Length Elongation in Children with Basic Intermittent Exotropia: A 12-Month Observational Study.

The aim of the study was to investigate the association of parameters related to accommodation and convergence and axial elongation in basic intermittent exotropia (IXT) patients and the potential clinical predictors of axial length (AL) growth. A total of 140 basic IXT patients were recruited in this study. The medians of AL growth in different age brackets were chosen to divide the subjects into group A (slower axial elongation group, n = 69) and group B (faster axial elongation group, n = 71). Parameters of dominant and nondominant eyes were compared and analyzed during the 12-month follow-up period. The parameters, including baseline refraction, angle of deviation, Newcastle control score (NCS), accommodative amplitude (AMP), accommodative facility (AMF), accommodative response, positive or negative relative accommodation (PRA/NRA), and near point of convergence (NPC), were analyzed via univariate and multivariate regression. Subjects in the faster axial elongation group tended to have more myopic spherical equivalents (t = 3.956, p &lt; 0.001), greater AMPs of dominant eyes (t = -2.238, p = 0.027), and fewer near points of convergence (t = 2.347, p = 0.020) than in the slower axial elongation group. For dominant eyes, logistic and linear regression analysis revealed that more negative spherical equivalents (OR = 0.603, p &lt; 0.001; β = -0.045, p &lt; 0.001), greater AMPs (OR = 1.201, p = 0.027; β = 0.023, p = 0.010), and less near points of convergence (OR = 0.883, p = 0.021; β = -0.012, p = 0.019) were correlated with the faster axial elongation. For nondominant eyes, a more myopic spherical equivalent (OR = 0.682; p = 0.001; β = -0.029, p = 0.005) was the only parameter correlated with faster axial elongation through regression analysis. In children with basic IXT, faster axial elongation in the dominant eyes was associated with more myopic spherical equivalents, greater AMPs, and lower NPCs. These accommodative parameters can serve as potential clinical indicators for monitoring myopia progression in addition to AL.

Comparison of clinical characteristics in intermittent exotropia patients with different visual perception and oculomotor control

Objective: To explore the clinical characteristics of intermittent exotropia (IXT) patients with different visual perception and oculomotor control. Methods: A cross-sectional study was conducted. Minor IXT patients between March 2021 and May 2023 at Beijing Tongren Hospital were enrolled. Demographic characteristics were recorded, and visual perception and oculomotor control were evaluated. The patients were divided into simultaneous vision disappearing and existing groups, fusion disappearing and existing groups, distant stereoscopic vision disappearing and normal groups, and near stereoscopic vision injury and normal groups. Statistical description was performed by using M (Q1, Q3). Rank sum test was used to compare the Revised Newcastle Control Score (RNCS), near and far strabismus degree, duration of disease, and age of onset among different groups. The correlation between visual perception and oculomotor control and the correlation of duration of disease and age of onset with visual perception and oculomotor control were analyzed by Pearson correlation analysis. Results: A total of 381 patients were enrolled, including 189 males and 192 females, with a median age of 7 (6, 9) years. The incidence of normal visual perception was 19.4% (74/381). Compared with simultaneous vision and fusion existing groups and distant and near stereoscopic vision normal groups, the RNCS [7 (5, 9) vs 4 (3, 6), 6 (5, 8) vs 4 (3, 6), 5 (4, 7) vs 3 (3, 5), and 5 (3, 6) vs 4 (3, 6)], near strabismus degree [65Δ (60Δ, 80Δ) vs 40Δ (30Δ, 50Δ), 60Δ (45Δ, 65Δ) vs 40Δ (30Δ, 50Δ), 50Δ (40Δ, 60Δ) vs 35Δ (30Δ, 45Δ), and 45Δ (30Δ, 60Δ) vs 40Δ (30Δ, 50Δ)] and far strabismus degree [60Δ (50Δ, 75Δ) vs 35Δ (25Δ, 50Δ), 55Δ (41Δ, 65Δ) vs 35Δ (25Δ, 45Δ), 45Δ (30Δ, 60Δ) vs 35Δ (25Δ, 45Δ), and 40Δ (30Δ, 60Δ) vs 35Δ (25Δ, 45Δ)] increased significantly in disappearing simultaneous vision, fusion, and distant stereoscopic vision groups and injury near stereoscopic vision group (all P<0.05). Compared with simultaneous vision and fusion existing groups and distant stereoscopic vision normal group, duration of disease was significant longer in disappearing simultaneous vision, fusion, and distant stereoscopic vision groups [3 (1, 5) years vs 2 (1, 3) years, 2 (1, 4) years vs 1 (1, 3) years, 2 (1, 4) years vs 1 (1, 3) years, all P<0.05]. The age of onset in disappearing distant stereoscopic vision group was significantly lower than normal distant stereoscopic vision group [5 (3, 7) years vs 6 (4, 8) years, P=0.005]. Pearson correlation analysis showed that subjective angle and random dot stereogram (RDS) stereoacuity were positive correlation with RNCS, and the near and far strabismus degree (r=0.414, 0.516, and 0.559, all P<0.001; r=0.153, 0.142, and 0.173, all P<0.05). Subjective angle, RNCS, and the near and far strabismus degree were positive correlation with duration of disease (r=0.238, 0.195, 0.236, 0.239, all P<0.001) and negative correlation with age of onset (r=-0.184, -0.279, -0.112, -0.147, all P<0.05). Conclusions: Nearly 20% of IXT patients have normal visual perception. With the longer duration of disease or lower age of onset, the incidence of abnormal visual perception is higher and injury of visual perception and oculomotor control is more serious.

Revisiting the surgical table: An analysis of surgical dose-response in Asian exotropia

BackgroundPrevious research on the factors associated with surgical dose-response in strabismus surgery for exotropia has yielded inconsistent results. This study determined the factors influencing surgical dose-response in exotropia patients who underwent recession and resection (R&R). MethodsExotropia patients who underwent unilateral R&R at the National Taiwan University Hospital between 2006 and 2021 were evaluated. Deviation-angle differences in prism diopters (PD) were measured preoperatively and at 1 month postoperatively. Surgical dose-response (PD/mm) was defined as the difference in deviation angle (in PD) divided by the surgical dose in millimeters. Linear and non-linear regression models were used to evaluate the influence of variables including age, sex, axial length, and preoperative deviation on surgical dose-response. ResultsOverall, 295 patients (162 children; 133 adults) were included. Average surgical dose-response in the pediatric and adult groups was 2.82 ± 0.60 PD/mm and 3.02 ± 0.62 PD/mm, respectively. Male sex was negatively correlated with surgical dose-response in children. The surgical dose-response was larger in adults with longer axial length (>25.64 mm) and patients with larger preoperative deviation (>42.6 PD and >38.7 PD in pediatric and adult groups, respectively). Surgical dose-responses peaked at 35.1 years. ConclusionAge, axial length, and preoperative deviation have a nonlinear effect on surgical dose-responses in exotropia patients undergoing R&R. Surgical dose-responses were larger in patients in young adulthood, with longer axial length and larger preoperative deviation angle. A table with fitted values for surgical dose-response based on age, axial length, and preoperative deviation was established for clinical reference.

Strabismus management in retinoblastoma survivors

PurposeTo report the result of strabismus surgery in eye-salvaged retinoblastoma (Rb) patients.MethodsA retrospective case series including 18 patients with Rb and strabismus who underwent strabismus surgery after completing tumor treatment by a single pediatric ophthalmologist.ResultsA 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.ConclusionStrabismus 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.

SURGICAL OUTCOMES OF STRABISMUS CORRECTION IN LARGE ANGLE EXOTROPIA

Introduction and Objective: Surgery is one of the treatment options for strabismus. The success rates of surgical interventions, as reported in a number of different studies, vary widely. There is no database of surgical outcome in large angle exotropia patient undergoing surgery in Semarang, Central Java. This study aims to evaluate the surgical outcome of strabismus correction in large angle exotropia in Dr. Kariadi General Hospital. Methods: A retrospective study held from the medical record of patients with diagnosis large angle (&gt;50?) exotropia undergoing strabismus correction surgery from January 2020-December 2022 in Dr. Kariadi General Hospital, Semarang. The clinical characteristics: sex, age, angle of exodeviation, amblyopia condition, sensory deprivation, and postoperative alignment were obtained. Surgical outcome measured with follow up of angle deviation in one month dan three months follow up after surgery. Result: Totally 59 large angle exotropia patients were obtained with 31 (53%) were woman and 28 (47%) were man, range aged 1 year to 53 years old had preoperative angle of exodeviation 51-&gt;85 ?, 6 (10%) had amblyopia, 11(18.6%) had sensory deprivation. By the 3 months post-operative visit, 100% of all patients reported orthophoria. Conclusion: This study found the outcome of strabismus correction for large angle exotropia is satisfactory. Two- or three-muscle surgery provides an effective means for treatment of large angle exotropia. Keywords: large angle exotropia, exodeviation, strabismus

Comparison of retinal nerve fiber layer thickness between monocular and alternating exotropia in patients with intermittent exotropia.

To investigate differences in intraocular structure based on the presence or absence of fixation preference in children with intermittent exotropia (IXT) by comparing the thickness of the retinal nerve fiber layer (RNFL). From October 2018 to March 2022, RNFL thickness was retrospectively analyzed using spectral domain optical coherence tomography. Participants had uncorrected visual acuity of 20/20, refractive errors close to emmetropia, and no anisometropia. The patients were divided into monocular and alternating exotropia groups through a cover-uncover test. The average and sectoral thickness of the RNFL in both groups were compared. The average global thickness and average thickness of each of the six sectors of the RNFL did not significantly differ between dominant and non-dominant eyes in the monocular exotropia group and between right and left eyes in the alternating exotropia group. The thickness did not significantly differ between the monocular exotropia group and the right or left eye of the alternating exotropia group. Interocular differences in RNFL thickness were negative in the monocular exotropia group (dominant eye-non-dominant eye) and positive in the alternating exotropia group (right eye-left eye) for the average, inferonasal, and inferior sectors, exhibiting statistically significant between-group differences (p = 0.019, p = 0.003, p = 0.023, respectively). In children with IXT without obvious refractive error, there was a significant interocular difference in RNFL thickness of the average, inferonasal, and inferior sectors between monocular and alternating exotropia groups. The presence of fixation preference may affect RNFL thickness.

Clinical features and change in incidence of acute acquired comitant esotropia: a 15-year single-centre study in South Korea.

We investigated the clinical features and change in incidence of AACE in South Korea. We reviewed the medical records of AACE patients who visited the Strabismus Clinic of at a tertiary referral hospital from 2007 to 2021. Clinical features were retrieved, including age at onset, angle of deviation, refractive errors, neuroimaging findings, and treatment outcomes. For each year, the proportion of new AACE patients among all new patients who visited the clinic, and the ratio of new AACE patients to new intermittent exotropia (IXT) patients, were analysed to estimate the incidence of AACE. Overall, 59 patients were included in the study. The mean age of the patients was 24.7 ± 9.3 years; the incidence of AACE was highest in teenagers and young adults. No patients had a history of visual occlusion, recent physical or psychological stress, or uncorrected myopia, unlike to classic AACE; moreover, no patients exhibited abnormalities in neuroimaging. There was a significantly increasing trend in the proportion of new AACE patients among all new patients (linear regression analysis, R2 = 0.778, p < 0.001). There was also a significantly increasing trend in the ratio of new AACE patients to new IXT patients (R2 = 0.803, p < 0.001). A new type of AACE, distinct from the classic types, is increasingly common in South Korea; this increasing incidence also appears to be a global phenomenon. Large-scale investigations are needed to define the exact clinical features, incidence, and pathophysiology of this new type of AACE.

The profiles and clinical significance of extraocular muscle-expressed lncRNAs and mRNAs in oculomotor nerve palsy.

Oculomotor nerve palsy (ONP) arises from primary abnormalities in the central neural pathways that control the extraocular muscles (EOMs). Long non-coding RNAs (lncRNAs) have been found to be involved in the pathogenesis of various neuroparalytic diseases. However, little is known about the role of lncRNAs in ONP. We collected medial rectus muscle tissue from ONP and constant exotropia (CXT) patients during strabismus surgeries for RNA sequencing analysis. Differentially expressed mRNAs and lncRNAs were revealed and included in the functional enrichment analysis. Co-expression analysis was conducted between these differentially expressed mRNAs and lncRNAs, followed by target gene prediction of differentially expressed lncRNAs. In addition, lncRNA-microRNA and lncRNA-transcription factor-mRNA interaction networks were constructed to further elaborate the pathological changes in medial rectus muscle of ONP. Furthermore, RT-qPCR was applied to further validate the expression levels of important lncRNAs and mRNAs, whose clinical significance was examined by receiver operating characteristic (ROC) curve analysis. A total of 618 differentially expressed lncRNAs and 322 differentially expressed mRNAs were identified. The up-regulated mRNAs were significantly related to cholinergic synaptic transmission (such as CHRM3 and CHRND) and the components and metabolism of extracellular matrix (such as CHI3L1 and COL19A1), while the down-regulated mRNAs were significantly correlated with the composition (such as MYH7 and MYL3) and contraction force (such as MYH7 and TNNT1) of muscle fibers. Co-expression analysis and target gene prediction revealed the strong correlation between MYH7 and NR_126491.1 as well as MYOD1 and ENST00000524479. Moreover, the differential expressions of lncRNAs (XR_001739409.1, NR_024160.1 and XR_001738373.1) and mRNAs (CDKN1A, MYOG, MYOD1, MYBPH, TMEM64, STATH, and MYL3) were validated by RT-qPCR. ROC curve analysis showed that lncRNAs (XR_001739409.1, NR_024160.1, and NR_002766.2) and mRNAs (CDKN1A, MYOG, MYOD1, MYBPH, TMEM64, and STATH) might be promising biomarkers of ONP. These results may shed light on the molecular biology of EOMs of ONP, as well as the possible correlation of lncRNAs and mRNAs with clinical practice.

Comparative Analysis of Strabismus Measurement Using a Video Oculagraphy System and Alternate Prism Cover Test.

The aim of the study was to compare distance vision measurements obtained with video oculography (VOG) and an alternate prism cover test (APCT). Single-center, retrospective, and cross-sectional. Eighty-seven subjects with strabismus were included. All patients underwent an optometric examination. The measurement of strabismus in distance vision was performed with the best optical correction using the APCT and the VOG GazeLab. Subjects were divided according to the type of strabismus; 41 were esotropic and 46 were exotropic. The general comparison of APCT and VOG showed a mean difference of 0.60±2.74 prism diopters (Δ), not observing statistical differences between both methods ( P =0.059) and presenting a correlation of 0.976 ( P <0.001). Using APCT, the mean amount of esotropia for the group was 18.31±11.64 Δ and that of exotropia was 19.62±8.80 Δ. Compared with the VOG, the mean value of esotropia for the group was 18.65±11.65 Δ and that of exotropia was 19.48±8.62 Δ. The means are statistically different for the esotropia group ( P =0.005) but not for the exotropia group ( P =0.318). There was a high direct correlation between the methods of measurement for both the esotropic ( R =0.980; P <0.001) and exotropic patients ( R =0.975; P <0.001). Bland-Altman analysis shows a mean difference of 1.37±2.76 Δ for the esotropia patients and 0.31±2.66 Δ for the exotropic patients, respectively. This study demonstrated comparable results in measuring strabismus between VOG and APTC for esotropia and exotropia, with an excellent correlation between both methods and good agreement, especially in subjects with exotropia.

Identification and characterization of differentially expressed circular RNAs in extraocular muscle of oculomotor nerve palsy

BackgroundOculomotor nerve palsy (ONP) is a neuroparalytic disorder resulting in dysfunction of innervating extraocular muscles (EOMs), of which the pathological characteristics remain underexplored.MethodsIn this study, medial rectus muscle tissue samples from four ONP patients and four constant exotropia (CXT) patients were collected for RNA sequencing. Differentially expressed circular RNAs (circRNAs) were identified and included in functional enrichment analysis, followed by interaction analysis with microRNAs and mRNAs as well as RNA binding proteins. Furthermore, RT-qPCR was used to validate the expression level of the differentially expressed circRNAs.ResultsA total of 84 differentially expressed circRNAs were identified from 10,504 predicted circRNAs. Functional enrichment analysis indicated that the differentially expressed circRNAs significantly correlated with skeletal muscle contraction. In addition, interaction analyses showed that up-regulated circRNA_03628 was significantly interacted with RNA binding protein AGO2 and EIF4A3 as well as microRNA hsa-miR-188-5p and hsa-miR-4529-5p. The up-regulation of circRNA_03628 was validated by RT-qPCR, followed by further elaboration of the expression, location and clinical significance of circRNA_03628 in EOMs of ONP.ConclusionsOur study may shed light on the role of differentially expressed circRNAs, especially circRNA_03628, in the pathological changes of EOMs in ONP.

Long-Term Surgical Outcomes of Bilateral Symmetrical Superior Oblique Nasal Tenotomy in Patients of Large A-Pattern Exotropia.

To report the long-term outcomes of bilateral symmetrical superior oblique (SO) nasal tenotomy in patients with large A-pattern exotropia (≥25 prism diopter [PD]). This retrospective study was conducted on 15 patients (aged: 4-28 years) of large A-pattern exotropia. An A-pattern was defined as >10 PD difference between up and down gaze at 6 m by use of the alternate prism cover test. Objective ocular torsion was assessed by fundus photography and subjective torsion by double Maddox rod test. All patients underwent horizontal muscle surgery according to the primary position horizontal deviation and bilateral symmetrical SO nasal tenotomy for A-pattern. Surgical success was defined as postoperative A-pattern of ≤10 PD, the absence of vertical and torsional diplopia, and the absence of V-pattern. The minimum follow-up period was 24 months. A total of 15 patients of large A-pattern exotropia (7 males and 8 females) with a mean age of 17.09 ± 7.9 years were included in the study. All patients had bilateral SO overaction of grade +3 or +4 with a mean preoperative A-pattern of 30.3 ± 3.9 PD. At 24 months of follow-up, esotropia in down gaze (V-pattern) was present in four patients with a mean of 11.25 ± 2.5 PD, (range, 10-15 PD). The rest of the 11 patients maintained successful alignment with a mean A-pattern of 3.18 ± 1.17 PD, (range, 2-5 PD). There was significant A-pattern collapse with a mean of 31 ± 9.1 PD after 2 years of follow-up, which was significantly associated with preoperative A-pattern (Pearson correlation, r = 0.7; t[15] = 4.0; P = 0.002). The mean of pre- and postoperative objective ocular torsion was found to be -0.5 ± 4° and -4.8 ± 3.8° with a mean extorsion effect of 4.67 ± 3.85°. There was a statistically significant difference between pre- and postoperative ocular torsion (°) (t [30] = 5.42; P < 0.001), the change in ocular torsion was significantly associated with preoperative torsion (Pearson correlation, r = 0.5; t [30] = 7.2; P < 0.001). None of the patients had subjective torsion on the double Maddox rod test pre- and postoperatively. Bilateral symmetrical SO nasal tenotomy is effective in cases with large A-pattern (>25 PD). The reduction of A-pattern and postoperative change in fundus torsion have a positive correlation with preoperative A-pattern and preoperative torsion, respectively.

Comparison of Myopia Progression among Myopic Children with Intermittent Exotropia and No Strabismus.

Myopia is a highly prevalent condition in the pediatric population that is commonly comorbid with intermittent exotropia. Our study found a trend toward significance in the reduction of myopia progression with strabismus correction surgery. Further investigations characterizing the interaction between myopia and strabismus may help inform future management guidelines. This study describes and compares myopic progression in the pediatric population with and without intermittent exotropia and its interaction with corrective strabismus surgery. This study analyzed a retrospective cohort of 1239 pediatric myopic patients who were evaluated by pediatric ophthalmologists and optometrists at a tertiary care center from 2012 to 2020. The main outcome measures were the trends in refractive error over time in those with and without intermittent exotropia as well as trends in those who did and did not undergo strabismus surgery. A total of 275 patients (22%) were identified to have intermittent exotropia, and 12 (4.4%) from this group underwent surgical correction in the study period. No statistically significant difference was identified in myopic progression between those with intermittent exotropia and those without strabismus, and no difference was found in mean annual spherical equivalent change between intermittent exotropia patients who did not undergo surgery compared with those who did. Pediatric myopic patients generally experience progression in the condition for several years independent of concurrent intermittent exotropia. Corrective strabismus surgery was not found to alter the natural history of myopia in children, although a reduction in myopic progression in surgically treated patients trended toward significance. Increases in the prevalence of different treatment strategies will necessitate further studies to determine best practices for this population.

Characteristics of Guyton's exaggerated forced duction test (FDT) and torsional FDT in congenital superior oblique palsy

Objective: To investigate the characteristics of Guyton's exaggerated forced duction test (FDT) and torsional FDT in patients with congenital superior oblique palsy (CSOP) and their correlation with clinical features. Methods: This cross-sectional study included single-eye CSOP patients and intermittent exotropia (IXT) patients scheduled for strabismus correction surgery at Tianjin Eye Hospital from September 2021 to March 2022. Prior to surgery, measurements of fovea-disc angle (FDA) and maximum cross-sectional area of the superior oblique muscle (max-CSA) were obtained in both eyes of the patients. The Guyton's exaggerated FDT and torsional FDT were performed intraoperatively to assess the degree of superior oblique muscle relaxation. The characteristics of the two FDT tests and their correlation with vertical strabismus angle, FDA, and max-CSA were analyzed. Statistical analyses were conducted using t-test, ANOVA, Tukey's test, Mann-Whitney U test, and chi-square test. Results: A total of 42 patients (84 eyes) were included in the study, including 19 IXT patients (38 eyes) and 23 CSOP patients (46 eyes, 23 eyes with palsy and 23 eyes without palsy). There were no statistically significant differences in gender composition or age between the IXT and CSOP patients (all P>0.05). The degrees of superior oblique muscle relaxation measured by the Guyton's exaggerated FDT were (-2.52±1.20), (-0.35±0.71), and (-0.03±0.16) for the palsy eye, non-palsy eye, and IXT eyes, respectively, showing significant differences (F=88.10, P<0.001). The torsional FDT measurements yielded external rotation angles of 48.70°±9.67°, 37.39°±5.40°, and 38.95°±2.88° for the palsy eye, non-palsy eye, and IXT eyes, respectively, showing significant differences (F=16.67, P<0.001). There was no statistically significant difference in internal rotation angles (F=2.36, P=0.100). The FDA values were-12.11°±7.42° for IXT patients and-19.02°±4.95° for CSOP patients, while the max-CSA values for the palsy eye and non-palsy eye of CSOP patients were (7.59±4.69) mm² and (11.63±3.64) mm², respectively, all showing significant differences (all P<0.001). The degree of superior oblique muscle tendon relaxation assessed by the Guyton's exaggerated FDT was negatively correlated with the external rotation angle measured by the torsional FDT (r=-0.64, P=0.001). They were positively correlated with max-CSA (r=0.45, P=0.030) and negatively correlated with max-CSA (r=-0.52, P=0.011). However, there was no correlation with vertical and rotational strabismus angle (r=-0.12, P=0.579; r=0.33, P=0.126) and FDA (r=-0.02, P=0.921; r=-0.23, P=0.309). Conclusions: Guyton's exaggerated FDT and torsional FDT can both assess the degree of superior oblique muscle relaxation in patients with CSOP. Furthermore, these two tests are correlated with changes in superior oblique muscle morphology. However, FDT cannot reflect the degree of vertical and rotational strabismus in patients.

Comparison between bupivacaine injection and mini-tenotomy in the management of horizontal small angle strabismus in children

ABSTRACT Purpose To compare the outcome of bupivacaine (BUP) injection vs mini-tenotomy of extra-ocular muscles in treating small angle horizontal strabismus in children. Methods A prospective comparative study that included a total of 40 patients. Twenty patients received 3 ml of 0.75% Bupivacaine (BUP) injection in both medial recti in case of exotropia and in both lateral recti in case of esotropia. MRI orbit was performed before and 30–60 days’ post injection of bupivacaine to estimate changes in muscle size. Mini-tenotomy was done in the other 20 patients, performed on both lateral recti in case of exotropia and on both medial recti in case of esotropia. Results Mean change of alignment at the end of 6 months in exotropic patients in bupivacaine group was 5.50 ± 4.10 PD and in esotropia patients 4.00 ± 3.38 PD with an average increase in muscle thickness of 0.12 mm ± 0.08 and 0.13 mm ± 0.09 in exotropia and esotropia, respectively. There was an average increase in volume 23 mm3 ± 17.3 and 17.00 mm3 ± 9.50 in exotropia and esotropia, respectively, as measured with MRI. The mean change of alignment in mini-tenotomy was 5.33 ± 4.12 PD, 5.75 ± 4.95 PD in exotropia and esotropia, respectively. Conclusion Bupivacaine and mini-tenotomy are safe and effective alternative treatment, that improved eye alignment in 65% of patients with small angle horizontal deviation.

Characteristics and risk factors for spontaneous and postoperative consecutive exotropia in children with esotropia.

To investigate the risk factors for the development of consecutive exotropia (CXT) by comparing patients with spontaneous or postoperative CXT during follow-up with another group of patients who had no deviation or less than 10 prism dioptre (PD) esotropia. In this retrospective cohort study, 6 patients with spontaneous CXT (group A), 13 patients with postoperative CXT (group B), and 39 patients with no exotropia (group C) were enrolled. Probable risk factors for CXT were evaluated among the groups. Kruskal-Wallis H test was used to determine if any significant differences were present among the groups. Fisher's exact test or Mann-Whitney U test was used for univariate analyses to compare differences between case groups or between case and control groups. The Bonferroni method was used to conduct multiple comparisons. The follow-up period of spontaneous CXT patients was significantly longer than that of postoperative CXT and nonconsecutive exotropia patients (p = 0.035 and p < 0.001, respectively). The interval between alignment and CXT onset in spontaneous CXT patients was slightly longer than that in postoperative CXT patients, but not significantly difference (6.50 vs. 5.00 years, p = 0.072). Vertical deviation was associated with a high risk of postoperative CXT (p = 0.001). Most [38 (97.44%)] nonconsecutive exotropia patients had fusion; conversely, the absence of fusion function (p < 0.001) as well as stereoacuity (p = 0.029) were associated with a high risk of CXT. Vertical deviation and poor binocular function are strongly associated with a high risk of CXT. Children with spontaneous CXT are highly recommended to be followed-up long-term, while they maintain long-term ocular alignment before developing consecutive exotropia from comitant esotropia (CE).

Clinical significance of CTGF and Cry61 protein in extraocular muscles of strabismic patients.

To investigate the relationship between clinical features and protein amounts of Cysteine-rich 61 (Cyr61/CCN1) and connective tissue growth factor (CTGF/CCN2), which are vital components and regulators of the extracellular matrix in resected muscles from strabismus surgery. Strabismus patients who were diagnosed with horizontal concomitant strabismus or inferior oblique overaction (IOOA) and required extraocular muscles (EOMs) resection to correct eye position were included in this study. The protein amounts were measured by enzyme-linked immunosorbent assay (ELISA) in resected EOMs. Multivariable linear regression was used to investigate the associations, adjusting for gender, age (continuous), amblyopia, and disease duration. A total of 141 muscles (including 38 lateral, 81 medial rectus, and 22 inferior oblique muscles) from 128 patients were collected in this study. The amount of Cry61 and CTGF per millimeter was significantly negatively associated with deviation angle in intermittent exotropia patients (Cry61: β, - 1.44; 95%CI, - 2.79 to - 0.10, p = 0.035; CTGF: β, - 3.14; 95%CI, - 5.06 to - 1.22, p = 0.002). The same relationship was also detected in the partially accommodative and non-accommodative esotropia patients, although it was not statistically significant (Cry61: β, - 2.40; 95%CI, - 5.05 to 0.24; p = 0.073; CTGF: β, - 3.47; 95%CI, - 9.18 to 2.87; p = 0.269). The amount of Cry61 and CTGF per millimeter showed significant associations with the degree of IOOA (p < 0.05). Taken together, our results demonstrated a significant relationship between deviation angle and protein amount of Cry61 and CTGF and implied that Cry61 and CTGF may play important roles in modulation of EOM contractility, which provide new insights into strabismus pathogenesis.

Long-term surgical outcomes of basic-type exotropia in patients with hyperopia

BackgroundTo investigate the surgical outcomes of basic-type exotropia in patients with hyperopia.MethodsThe medical records of patients who underwent surgery for basic-type exotropia and had been followed up for ≥ 2 years were retrospectively recruited. Patients with myopia and spherical equivalent (SE) < -1.0 diopters (D) were excluded. The patients were classified according to the SE: group H had a SE ≥ + 1.0 D, and group E had -1.0 ≤ SE < + 1.0 D. The surgical success rate and sensory outcome were compared. Surgical success was defined as exodeviation ≤ 10 prism diopters (PD) and esodeviation ≤ 5 PD at 6 m fixation. Stereoacuity was measured using the Titmus Preschool Stereoacuity Test.ResultsSeventy-five patients (24 males and 51 females, mean age 5.1 ± 2.6 years, range 2.7–14.8) were included. The SE ranged from -0.9 to 4.4 and 21 patients were classified into group H and 54 into group E. The success rates were higher in group H than in group E during the entire follow-up period, but the differences were significant only at the final examination. At the final follow-up, 11 of the 21 (52.4%) patients in group H and 15 of the 54 (27.7%) in group E maintained successful alignment, whereas 10 (47.6%) and 38 (70.4%) patients exhibited recurrence. Overcorrection was exhibited in one (1.9%) patient in group E. Sensory results were comparable between the groups. The follow-up period did not differ between the two groups. The survival analysis showed no difference in the surgical results between the two groups.ConclusionsSurgery for basic-type intermittent exotropia resulted in superior outcomes in patients with hyperopia compared to those with emmetropia.

Evaluation of retinal microvasculature in exotropia with abnormal binocular vision by optical coherence tomography angiography

BackgroundTo explore the retinal microvasculature in large-angle concomitant exotropia patients with abnormal binocular vision using optical coherence tomography angiography (OCTA) analysis.MethodsOCTA images of 52 healthy and 100 strabismic eyes were analyzed to quantify the retinal thickness (RT), superficial capillary plexus (SCP), deep capillary plexus (DCP), and foveal avascular zone (FAZ). Paired t-tests were performed to compare differences between the two groups, the dominant eye and the deviated eye in the exotropia group, respectively. A p-value < 0.01 was considered significant.ResultsThe mean angle of deviation was 79.38 [± 25.64] (prism diopters, PD). There were significant differences in the DCP in deviated eyes between the exotropia group and the control group (fovea: p = 0.007; temporal: p = 0.014; nasal: p = 0.028; inferior: p = 0.013). The temporal SCP in the exotropia group was significantly higher than in the control group in deviated eyes (p = 0.020). No significant difference was found between dominant eyes and strabismic eyes (p > 0.01).ConclusionsThe study showed that OCTA revealed subnormal DCP in patients with large-angle exotropia and abnormal binocularity which may be related to retinal suppression. Changes in the macular microvasculature may provide valuable insights into the development of strabismus. Further studies are needed to determine the clinical relevance of this finding.Trial registrationThis trial is registered as ChiCTR2100052577 at www.Chictr.org.cn.