Distance stereopsis in patients with accommodative esotropia.

PURPOSE: We aimed to evaluate distance stereoacuity (DS) in patients with successfully treated accommodative esotropia (AET) and its association with other clinical factors. METHODS: The medical records of 176 children with refractive AET with a follow-up period ≥ 1 year were reviewed to identify a cohort of patients who achieved a stable alignment within 4 prism diopters (PD) of orthotropia at both distance and near fixation. Age of onset, duration of misalignment, uncorrected near and distance deviation, accommodative convergence/accommodation ratio, refractive error, presence of anisometropia and amblyopia, near stereopsis were evaluated as predictors of outcome. DS was measured using the Distance Randot Stereo test and near stereoacuity by Randot Stereotest. The patient group was compared with 50 age-matched normal controls for DS. RESULTS: Fifty-six patients were included, and 38 patients had DS at the final visit. All patients with DS attained uncontoured near stereopsis (UCNS). UCNS was present only in 11 patients without DS (p = 0.001). Anisometropia (p = 0.997), uncorrected near deviation (p = 0.224), distance deviation with correction (p = 0.255), and high hypermetropia (p = 0.998) were not associated with DS. The multivariable regression model showed a significant positive correlation between UCNS and DS (OR = 31.14 (95% CI 2.25-430.48); p = 0.01). Contoured near stereopsis outcome was significantly different between the patients with and without DS (p = 0.001 for animals and p = 0.003 for circles). Compared with the control group, the patient group yielded lower DS scores (p = 0.001). CONCLUSION: Distance Randot Stereotest can be useful in measuring binocular vision recovery after successful realignment in refractive AET patients. Patients attaining normal scores for near stereopsis tests after optical correction revealed subnormal thresholds for DS.

Acute acquired comitant esotropia associated with Lhermitte-Duclos disease: a case report.

BACKGROUND: Acute acquired comitant esotropia caused by prolonged near work, such as the use of digital devices, has been frequently reported in recent years. However, intracranial examination is necessary even for patients with nonparalytic comitant esotropia. Lhermitte-Duclos disease is a rare tumor that grows in layers in the cerebellum. Among those with this disease, cases of esotropia have been reported due to abduction limitation of the eye, but there have been no reports of comitant esotropia. Here, we report the case of a young woman with acute acquired comitant esotropia who was found to have Lhermitte-Duclos disease. CASE PRESENTATION: A 16-year-old Japanese female patient, whose ethnicity was Asian, was referred to our hospital for acute acquired comitant esotropia. Fundus examination revealed papilledema in both eyes, and magnetic resonance imaging of the head revealed a cerebellar tumor in the right cerebellum with obstructive hydrocephalus. She underwent partial tumor resection, and a histopathological diagnosis of Lhermitte-Duclos disease was obtained. However, comitant esotropia status remained unchanged, and she underwent strabismus surgery. Finally, diplopia disappeared completely. CONCLUSION: Neurological and intracranial imaging examinations are essential when acute acquired comitant esotropia is observed. Acute acquired comitant esotropia by Lhermitte-Duclos disease did not improve with partial tumor resection and required strabismus surgery, but good surgical results were obtained.

Genome-Wide Association Study with Three Control Cohorts of Japanese Patients with Esotropia and Exotropia of Comitant Strabismus and Idiopathic Superior Oblique Muscle Palsy.

Esotropia and exotropia in the entity of comitant strabismus are multifactorial diseases with both genetic and environmental backgrounds. Idiopathic superior oblique muscle palsy, as the predominant entity of non-comitant (paralytic) strabismus, also has a genetic background, as evidenced by varying degrees of muscle hypoplasia. A genome-wide association study (GWAS) was conducted of 711 Japanese patients with esotropia (n= 253), exotropia (n = 356), and idiopathic superior oblique muscle palsy (n = 102). The genotypes of single nucleotide polymorphisms (SNPs) were determined by Infinium Asian Screening Array. Three control cohorts from the Japanese population were used: two cohorts from BioBank Japan (BBJ) and the Nagahama Cohort. BBJ (180K) was genotyped by a different array, Illumina Infinium OmniExpressExome or HumanOmniExpress, while BBJ (ASA) and the Nagahama Cohort were genotyped by the same Asian array. After quality control of SNPs and individuals, common SNPs between the case cohort and the control cohort were chosen in the condition of genotyping by different arrays, while all SNPs genotyped by the same array were used for SNP imputation. The SNPs imputed with R-square values ≥ 0.3 were used to compare the case cohort of each entity or the combined entity with the control cohort. In comparison with BBJ (180K), the esotropia group and the exotropia group showed CDCA7 and HLA-F, respectively, as candidate genes at a significant level of p < 5 × 10-8, while the idiopathic superior oblique muscle palsy group showed DAB1 as a candidate gene which is involved in neuronal migration. DAB1 was also detected as a candidate in comparison with BBJ (ASA) and the Nagahama Cohort at a weak level of significance of p < 1 × 10-6. In comparison with BBJ (180K), RARB (retinoic acid receptor-ß) was detected as a candidate at a significant level of p < 5 × 10-8 in the combined group of esotropia, exotropia, and idiopathic superior oblique muscle palsy. In conclusion, a series of GWASs with three different control cohorts would be an effective method with which to search for candidate genes for multifactorial diseases such as strabismus.

Advances in the diagnosis and treatment of acute acquired comitant esotropia.

Acute acquired comitant esotropia (AACE) is mainly characterized by sudden onset, accompanied by diplopia, without extraocular muscles paralysis or ocular motility disorders. In recent years, the incidence of AACE has been increasing, researchers have found that this phenomenon may be related to the widespread use of electronic devices and the increase in the number of people working from home during the COVID-19 pandemic. However, its neural mechanisms have not been fully elucidated. This article primarily reviews the latest developments in the diagnosis and treatment of AACE from the perspectives of etiology and treatment methods, aiming to provide direction for future in-depth exploration of the pathogenesis and treatment approaches of this disease.

Exploring WNT2 polymorphisms in comitant strabismus: A genetic association study.

BACKGROUND: Strabismus is a complex oculomotor condition characterized by a misalignment of the visual axis. The genetics of strabismus are poorly defined although a few candidate genes have been identified, among which is the WNT2 gene. Our study was designed to assess the association of single nucleotide polymorphisms (SNPs) of WNT2 in Pakistani strabismus patients. METHODS: A total of six SNPs, three intronic and three in the 3́ untranslated region, were screened in the current study. Logistic regression was performed using a dominant, recessive and additive model to determine the association of SNPs with strabismus and its clinical subtypes: esotropia and exotropia. Furthermore, haplotype analysis was performed. RESULTS: Regression analysis revealed an association of rs2896218, rs3779550, rs2285544 and rs4730775 with strabismus under the dominant model. When analyzed separately, rs2896218 and rs2285544 were found to be associated with both esotropia and exotropia, while rs4730775 was significantly associated only with exotropia under the dominant model. Based on clinical parameters, rs2896218, rs2285544 and rs4730775 were also found to be associated with the group of strabismus patients who were diagnosed at birth, but not in the group of patients who were diagnosed later in life. Haplotype analysis revealed that the haplotype A T T (corresponding to rs2896218, rs3779550 and rs2285544) was significantly more prevalent in the strabismus group. CONCLUSION: Overall, the results of the present study suggest an association of WNT2 polymorphisms with strabismus and its subtypes in the Pakistani population, though further studies are needed to elucidate their role in strabismus etiology.

Medial Rectus Disinsertion for the Management of Large-Angle Sensory Esotropia.

Background and Objectives: The aim of the report is to report the outcomes of the medial rectus (MR) disinsertion procedure for the management of large-angle esotropia (ET) patients. Materials and Methods: This is a retrospective case series of patients with large-angle ET who underwent an MR disinsertion procedure between March 2012 to April 2022. The procedure happened accidentally during muscle surgery. The demographic and clinical data, including sex, age, visual acuity, pre- and postoperative angle of strabismus, duction limitations, results of intraoperative forced duction tests, and follow-up duration were collected from medical records. Results: Five patients were enrolled in this study. The mean age was 62.2 ± 9.8 years, and the mean follow-up was 24.8 ± 8.7 months. The ET at the primary position of gaze was 92.0 ± 17.9 prism diopters (PD) before MR disinsertion and 38.0 ± 29.5 PD after MR disinsertion only. Abduction deficiency was -4 before after MR disinsertion, which improved to -1 at the last follow-up. Conclusions: The results of MR disinsertion were not as frustrating as anticipated. MR disinsertion may be considered in patients with large-angle sensory ET who refuse surgery on the opposite eye.

Surgical management of unilateral restrictive strabismus in an 8-month-old dog.

CASE HISTORY: An 8-month-old male, entire, mixed-breed dog was presented with a 1-month history of left exophthalmos and green mucopurulent ocular discharge. Subsequently, exophthalmos resolved but esotropia (medial strabismus) developed in the left eye, prompting referral to an ophthalmologist. CLINICAL FINDINGS: At the initial referral consultation, enophthalmos and esotropia of the left eye were identified. The patient showed mild improvement after a 3-week tapering course of oral prednisolone and doxycycline. MRI was performed and showed left medial rectus muscle atrophy with increased contrast enhancement which was consistent with chronic extraocular muscle myositis (EOM). A forced duction test was performed to confirm the diagnosis of fibrosing esotropia, which is likely a sequela of chronic EOM. DIAGNOSIS: Fibrosing esotropia presumably caused by untreated EOM. TREATMENT AND OUTCOME: One month later, esotropia progressed to a marked ventro-medial strabismus resulting in visual deprivation. Surgical release of the ventral oblique, medial and ventral recti muscles was performed, resulting in immediate resolution of the enophthalmos. Despite a tapering post-operative course of oral prednisolone, mild esotropia was present 4 weeks later. In an effort to stabilise the globe position, the low dose of prednisolone was increased to a higher anti-inflammatory dose before slowly tapering over 2 months. The vision in the left eye was improved after surgery and has been maintained since without further treatment. CLINICAL RELEVANCE: This is the first documented case of fibrosing esotropia in a young dog with prior signs of acute exophthalmos. Fibrosing esotropia has been documented in certain breeds or as a sequela to chronic EOM. In this patient, it was presumably caused by EOM, which was strongly supported by the case history, progression and MRI findings. Most historical reports of EOM described it as a bilateral condition that resolves with systemic corticosteroids at an anti-inflammatory dose. EOM has been shown to also present unilaterally and it can progress to strabismus if not promptly recognised and treated with systemic steroids. Surgical management can restore vision when severe strabismus results in visual deprivation.

Factors influencing the therapeutic effect of hyperopic correction on esotropia in patients with partially accommodative esotropia.

OBJECTIVES: To collate data on partially accommodative esotropia (PAET) to better understand this condition's aetiology and to evaluate and predict the therapeutic effect of a hyperopic correction on PAET. METHODS: Eighty-nine consecutive patients diagnosed with PAET with a spherical equivalent (SE) refractive error >+2.50 D were included in this retrospective review. Clinical characteristics, including gender, age, SE, angle of esodeviation, accommodative convergence/accommodation (AC/A) ratio, near-distance disparity (NDD) and anatomical features of the rectus muscles were compared among different PAET subgroups. Multiple linear regression was used to identify independent factors that influenced the therapeutic effect of a hyperopic correction on esotropia. RESULTS: No significant differences were observed for the angle of esodeviation as a function of age in individuals with PAET. The incidence of SE in PAET participants >9 years old was significantly greater than in those <5 and 6-8 years of age. The therapeutic effect of hyperopic correction on esotropia was positively associated with SE both at distance and near. In addition, the limbus insertion distance (LID) of the lateral rectus (LR) muscle was positively associated with NDD at distance, but negatively associated at near. CONCLUSION: A greater incidence of hyperopia was observed in older (>9 years old) PAET patients. A hyperopic correction had a greater effect on esotropia in individuals with a higher SE, larger LID of the LR muscle and a smaller NDD.

Pilot Study Assessing the Effect of Exam Room Length on the Measurement of Strabismus.

PURPOSE: Our study aims to investigate the effect of decreasing distance from the patient to the fixation target on the measurement of strabismus with a known distance-near disparity. METHODS: Strabismus measurements were taken by one pediatric ophthalmologist at our standard distance of 18 feet and compared to those taken at 16, 14, 12, and 10 feet from the fixation target. A clinically meaningful difference was defined as >2.5 prism diopters (PD), since a difference of that magnitude may alter surgical planning. RESULTS: Thirty-nine subjects, including 22 exotropes and 17 esotropes, were included in this study. Mean prism diopter difference (PDD) in the exotrope group at lengths of 16, 14, 12, and 10 feet compared to 18 feet were 1.3 (SD 1.9, range 0-6), 1.3 (SD 2.2, range 0-8), 1.7 (SD 3.2, range 0-14), and 2.8 (SD 4.4, range 0-14), respectively. Among esotropes, the mean PDD at the same distances were 1.1 (SD 1.9, range 0-7), 2.1 (SD 2.6, range 0-7), 3.9 (SD 4.9, range 0-19), and 4.3 (SD 5.1, range 0-19). The percentages of exotropes with a PDD of >2.5 at 16, 14, 12, and 10 feet compared to 18 feet were 13.6% (n = 3), 13.6% (n = 3), 18.2% (n = 4), and 27.3% (n = 6), respectively. In the esotrope group, 11.8% (n = 2), 35.3% (n = 6), 47.1% (n = 8), and 47.1% (n = 8) had a PDD of >2.5 at the same distances, respectively. CONCLUSION: This pilot study is the first to investigate the change in measured angle of strabismus at various non-mirrored distances from the patient to the fixation target. Our methodology defines a framework that could be used in a higher-powered study to further our understanding of the effect of room length on strabismus evaluation.

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

BACKGROUND: The 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. METHODS: This 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. RESULTS: Of 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). CONCLUSION: In 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.

Long-Term Effects of Botulinum Toxin A Versus Incisional Surgery for Management of Partially Accommodative Esotropia in Children: Comparison of Three Approaches.

PURPOSE: To compare the effect of bilateral medial rectus injection of botulinum toxin A (BTX-A), bilateral medial rectus muscle recession surgery (BMR rc), or unilateral medial rectus muscle recession combined with lateral rectus muscle resection surgery (R&R), in the management of partially accommodative esotropia (PAET) in children. DESIGN: Retrospective comparative clinical study. METHODS: The study cohort included 98 patients diagnosed with PAET who had BTX-A injection or incisional surgery between December 2014 and January 2023. The main outcome measures included motor and sensory results as well as complications. Follow-up was at least 12 months for all patients. RESULTS: There were 28 patients in the BTX-A group, 45 in the R&R group, and 25 in the BMR rc group. The motor success rates at distance and near fixation respectively were 50% (14/28) and 54% (15/28) in the BTX-A group, which were lower than that of the R&R group (78% [35/45], 84% [38/45]) and the BMR rc group (72% [18/25], 84% [21/25]) (P = .042 for near and P = .006 for distance). For patients with onset age <2.5 years old, there was no statistical difference amongst the 3 surgical approaches (P = .656). For patients with onset age ≥2.5 years, the motor success rate of the R&R group (81% [26/32]) and the BMR rc group (88% [14/16]) was higher than that in the BTX-A group (38% [5/13]; P = .004). There was no statistical difference in sensory outcomes for patients regardless of onset age or treatment methods (P > .05 for all). During follow-up, 4% (2/45) of patients in the R&R group and 20% (5/25) in the BMR rc group developed consecutive exotropia; no patient in the BTX-A group was overcorrected (P = .017). CONCLUSIONS: Bilateral medial rectus muscle injection with BTX-A in patients with PAET is a safe, accessible, and low-cost alternative. Although motor success rates were higher, overall, in patients treated with incisional surgery, for patients with earlier age of onset (≤ 2.5 years old), BTX-A injection may be preferred to incisional surgery. In older children treated with unilateral recession-resection surgery, fewer developed consecutive exotropia.

Clinical characteristics and surgical outcomes of acute acquired concomitant esotropia in a tertiary referral centre in Malaysia.

INTRODUCTION: Acute acquired concomitant esotropia (AACE) is an uncommon type of strabismus that occurs due to interruption of fusion. Limited data are available on AACE from Asian countries especially from the Southeast Asian region. We aim to describe the clinical profile and surgical outcomes of AACE patients treated in a tertiary hospital in Malaysia. MATERIALS AND METHODS: We conducted a retrospective study of 20 patients aged 3-26 years who were diagnosed with AACE and attended Hospital Universiti Sains Malaysia, Kelantan, Malaysia, between January 2020 and June 2022 with follow-up periods a minimum of 12 months. Demographic data, clinical features, neuroimaging, surgical intervention, and final ocular alignment outcomes were recorded. RESULTS: The mean age of onset was 9.7±6.6 years. There were equal numbers of males and females in this study. Hypermetropia (45%) was the leading refractive error. Angle of deviation of 50 PD and more was documented in 50% of the patients at distance, and 70% of the patients at near fixation. Fifty per cent had an absence of stereoacuity at presentation. Neuroimaging was performed on 13 patients (65%), and two patients had intracranial pathology. All patients underwent bilateral medial rectus recession during primary surgery. Eighteen patients (90%) experienced excessive near work-related activities for >4 hours per day, and 19 patients (95%) achieved good ocular alignment, restoration of stereoacuity and resolved diplopia after the surgical intervention. CONCLUSION: The mean age of onset was 9.7±6.6 years. Almost half of our patients had uncorrected hypermetropia. Furthermore, 90% of patients had excessive near-work activities, and 95% achieved good post-surgery alignment.

Surgical treatment outcomes in heavy eye syndrome - a case series.

Results: The study cohort comprised five patients, each presenting with unilateral high axial myopia and classic clinical features of HES, including large angle esotropia, hypotropia, and restricted abduction and supraduction. All patients displayed evident superotemporal globe prolapse on MRI imaging, corresponding to the downward displacement of the LR muscle and medial shift of the SR muscle.Following the surgical procedure, all patients demonstrated significant improvements in both vertical and horizontal deviations, effectively addressing the primary clinical manifestations of HES.Conclusions: In the management of HES, several surgical approaches have been explored, yielding mixed results. Our study, employing the technique of partial muscle splitting and scleral fixation, offers a promising avenue for effectively addressing this challenging condition. By adapting the full loop myopexy technique originally proposed by Yokoyama et al. we achieved satisfactory ocular alignment in all five patients. Notably, this approach mitigates the risk of anterior segment ischemia by preserving the unsecured portions of the SR and LR muscles along with MR retroequatorial myopexy.These findings support the consideration of this surgical technique as a safe and effective option for managing HES, providing both cosmetic and functional improvements to afflicted individuals.

Effect of 4-week preoperative prism adaptation in preventing postoperative residual esotropia.

BACKGROUND: Preoperative prism adaptation (PPA) simulates postoperative status and possibly can predict postoperative undercorrection before surgery in esotropia. The present study aimed to assess the effect of 4-week PPA in preventing postoperative residual esotropia. METHODS: Seventy-five (75) esotropes who had undergone surgery at a single strabismus center were retrospectively enrolled. They included 25 basic, 31 acute comitant, 10 partially accommodative, and 9 recurrent esotropia patients. The preoperative deviation angle, which had been determined using the alternating prism and cover test, was fully corrected with press-on prisms 4 weeks before surgery. If there was an increase of 5 PD or more of esodeviation, the prisms were changed accordingly at 2 weeks. The deviation angle measured at 4 weeks was determined as the surgical target angle. Patients were then divided into increase (≥ 5 PD increase of angle during 4-week PPA) and non-increase groups. Success was defined as either esodeviation of 8 PD or under or exodeviation of 5 PD or under at distance at postoperative 6 months. RESULTS: The increase group included 44 patients (58.7%). The mean deviation angle before PPA was 27.4 PD, and after the 4-week PPA, there was an average increase of 9.4 PD. The success rate was 90.9% in the increase group and 96.8% in the non-increase group (p = 0.316). There were no intergroup differences in preoperative clinical characteristics, esotropia types, postoperative deviation angle or postoperative near stereopsis (p > 0.05). CONCLUSIONS: The results of this study indicated a beneficial effect of 4-week PPA in esotropia of various types, specifically by uncovering the hidden esodeviation in the increase group and simulating the postoperative alignment in both the increase and the non-increase groups.

[The timing and challenges of early intervention for infantile esotropia].

Infantile esotropia is a common ophthalmic disease in children. A lot of clinical and basic research evidence suggests that early surgery enhances sensory and ocular motor development. However, the proper timing of surgery has been debated for decades. In addition, there is more likely instability of deviation in the preoperative evaluation of infants, and even if the patient achieved alignment after surgery, the defects in binocular vision may accompany for a lifetime. This article analyzes the difficulties and key points of early intervention for infantile esotropia, aiming to provide scientific ideas for the early treatment of children with infantile esotropia in China.

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.

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%.

Mechanisms for Positive Bielschowsky Head Tilt Testing in Horizontal Strabismus.

PURPOSE: To elucidate the induced effects of horizontal strabismus on the Bielschowsky Head Tilt Test (BHTT). DESIGN: Prospective clinical study. METHODS: Prospective analysis of BHTT testing in 85 patients with exotropia and 71 patients with esotropia who were examined in a strabismus clinic. RESULTS: Eighty-four of 85 patients with exotropia (98.82%) showed a positive BHTT with an induced hyperdeviation on the side of the tilt (to both sides in 67% and to one side in 32%). Fifty-seven of 71 patients with esotropia (80.2%) showed a positive BHTT with an induced hypodeviation on the side of the tilt (to both sides in 57.7% and to one side in 22.5%). These induced vertical deviations were greater in patients with larger horizontal deviations and in those with constant rather than intermittent deviations; however, they were not influenced by the presence or absence of associated primary oblique muscle overaction. CONCLUSIONS: Exotropia and esotropia produce hyperdeviations during BHTT testing, with a hyperdeviation on the side of the tilt observed in patients with exotropia, and hypotropia on the side of the tilt observed in patients with esotropia. These diametrical results are not attributable to any preexistent alteration of neurologic output inherent to these two forms of horizontal strabismus or to associated torsion. Rather, they arise directly from the altered anatomical positions of the two eyes, which cause the eyes to approximate their visual axes more closely to the vertical rectus muscles (in exotropia) and the oblique muscles (in esotropia), enabling the vertical actions of specific cyclovertical muscles to predominate in response to altered utricular output generated by the BHTT.

Doses of medial rectus muscle recessions for divergence insufficiency-type esotropia.

We evaluated whether doses of bilateral medial rectus recessions greater than Parks's tables yielded superior outcomes for adult-onset divergence insufficiency. Forty-two patients underwent bilateral medial rectus recessions. Dose was analyzed as the average total per muscle (surgery + suture adjustment if performed) and compared with the standard dose tables (based on preoperative distance esodeviation), as difference between dose performed and dose indicated by Parks's tables. Each participant was classified as having received either Parks's dose (within 0.5 mm) or a dose greater than Parks's dose. Success was defined as "rarely" or "never" diplopia in distance straight-ahead gaze and reading. For patients classified as success, the mean difference between actual surgical dose performed and Parks's dose was calculated. Success was 91% (29/32) in those receiving greater than Parks's dose versus 67% (6/9) with Parks's dose (difference = 24%; 95% CI, -5% to 60%). The mean surgical dose was 1.0 mm greater than Parks's tables for the 35 successes (at 10 weeks) versus 0.7 mm greater for the 6 failures (difference = 0.4 mm; 95% CI, -0.2 to 0.9). For medial rectus recessions in adult-onset divergence insufficiency-type esotropia, a surgical dose 1 mm greater than Parks's tables, for each muscle, is a reasonable strategy.