Factors influencing surgical success in concomitant horizontal strabismus

Objective: To identify the factors affecting surgical success in patients who underwent horizontal concomitant strabismus surgery. Materials and Methods: Medical records of 143 patients who underwent concomitant horizontal strabismus surgery and who were followed up at least 6 months at Ordu University, Faculty of Medicine, Department of Ophthalmology between January 2015 and December 2020 were reviewed retrospectively. Surgical success was defined as postoperative orthophoria or deviation angle of 10 prism diopters (PD) or less at 6 months after surgery. Results: 101 (70.63%) patients with esotropia and 42 (29.37%) patients with exotropia were operated. The mean follow-up period was 18.54 ± 17.51 months, the mean distance and near preoperative deviation were 46.94 ± 11.62 PD and 47.29 ± 11.81 PD, respectively. The surgical success was 83.92% in all patients, 87.13% in esotropic patients, and 76.19% in exotropic patients. Additional surgery was performed in 8 (5.59%) patients with >20 PD residual strabismus in the following year. Preoperative distance and near deviations were found to be significantly related with surgical success (p=0.020 and p=0.026). As the preoperative deviation decreases, the surgical success increases significantly. The deviation type, age at onset, age at the time of surgery, the interval between diagnosis and surgery, gender, or preoperative amblyopia were not significantly related to surgical success (p>0.05). Conclusion: The surgical success was found to be high following concomitant horizontal strabismus surgery. Since the preoperative deviation angle is the significant factor determining surgical success, preoperative evaluations should be done carefully. Patients and their parents should also be warned about the probability of additional surgery.

Altered Brain Structure and Spontaneous Functional Activity in Children With Concomitant Strabismus

Strabismus occurs in about 2% of children and may result in amblyopia or lazy eyes and loss of depth perception. However, whether/how long-term strabismus shapes the brain structure and functions in children with concomitant strabismus (CS) is still unclear. In this study, a total of 26 patients with CS and 28 age-, sex-, and education-matched healthy controls (HCs) underwent structural and resting-state functional magnetic resonance imaging examination. The cortical thickness and amplitude of low-frequency fluctuation (ALFF) were calculated to assess the structural and functional plasticity in children with CS. Compared with HCs group, patients with CS showed increased cortical thickness in the precentral gyrus and angular gyrus while decreased cortical thickness in the left intraparietal sulcus, parieto-occipital sulcus, superior and middle temporal gyrus, right ventral premotor cortex, anterior insula, orbitofrontal cortex, and paracentral lobule. Meanwhile, CS patients exhibited increased ALFF in the prefrontal cortex and superior temporal gyrus, and decreased ALFF in the caudate and hippocampus. These results show that children with CS have abnormal structure and function in brain regions subserving eye movement, controls, and high-order cognitive functions. Our findings revealed the structural and functional abnormalities induced by CS and may provide new insight into the underlying neural mechanisms for CS.

The features of diagnosis and treatmentof unilateral concomitant strabismus with visual fixation defect in preschool children

BACKGROUND:Particular difficulties in treatment of children with monolateral strabismus are associated with the presence of severe amblyopia in the squinting eye in combination with a visual fixation defect (acentral or intermittent). AIM:To assess the anatomical and functional status of children with visual fixation defects, to find out the causes of failures in treatment of this group of patients, to determine the tactics of their management. MATERIALS AND METHODS:The study included 92 children of preschool age (from 3 to 7 years) with monolateral concomitant strabismus. The follow-up period for the children ranged from 12 to 72 months. The average age of the examined children was 4.6 1.1 years. Three variants of visual fixation were identified in the squinting eye: central visual fixation (CVF) 68 eyes; intermittent visual fixation (IVF ) 7 eyes; and acentral visual fixation (AVF) 17 eyes. All patients underwent a comprehensive examination: visometry; strabometry; autorefractometry; determination of the critical frequency of light flashes; assessment of visual fixation; optical coherence tomography of the retina. All children underwent passive and active pleoptics. RESULTS:The visual acuity of children with CVF significantly increased due to pleoptics. At the same time in cases of IVF and even more in those of AVF, visual acuity remained significantly lower than that of the fixating eye, pleoptics were ineffective in this group of patients. In patients with CVF, the critical frequency of light flashes of the squinting eye increased in statistically significant figures, while in IVF and AVF, the difference between squinting and fixing eye remained. According to OCT data, changes in the macular area were detected in 18 (75%) eyes in patients with IVF and AVF, which allows us to distinguish organic pathology from amblyopia. CONCLUSIONS:In children with monolateral strabismus, it is necessary to determine visual fixation of the squinting eye. At IVF and AVF, it is mandatory to conduct optical coherence tomography of the macular area to exclude organic pathology. In patients with monolateral concomitant strabismus with IVF and AVF, surgery on oculomotor muscles is indicated.

On the Question of Amblyopia, Its Patterns and Treatment

Purpose. Description of various clinical forms of amblyopia and the effectiveness of their treatment in children. Material and methods. 242 children from 3 to 18 years old were examined: 110 boys (45.5%) and 132 girls (54.5%). The scope of visual examinations included the following: visometry (Tomey TCP-1000 LED), autorefractometry (Tomey TR-4000), keratometry (Pentacam), determination of the nature of visual fixation (HEINEBETA 200S manual ophthalmoscope). Results and conclusion. The approaches to treatment, depending on the underlying pathology, can be functional, surgical and combined. Functional treatment is indicated for amblyopia associated with concomitant strabismus (especially monolateral) and ametropia without improvement in correction. Surgery is very effective in relieving obscuration amblyopia (cataract extraction with IOL implantation, keratoconus with crosslinking). Key words: amblyopia, ametropia, pleoptics, orthoptics, obscuration.

Clinical Study of Concomitant Strabismus.

Background and Objectives: Strabismus is a condition in which there is misalignment of visual axes of two eyes. Concomitant strabismus is a condition in which the angle of deviation is constant in all the directions of gaze. Concomitant strabismus is further classified as convergent, divergent, hyperdeviation and hypodeviation. Major presenting complaints include cosmetic blemish, diminution of vision, asthenopic symptoms like headache, eye strain and diplopia. This study was conceptualized to study the clinical and ophthalmological profile of patients with concomitant strabismus, in order to generate evidence to manage this condition more effectively. Material and Methods : This cross-sectional, observational study was conducted over a period of two years in 120 patients with concomitant strabismus. Ocular history and visual acuity were recorded. Cover, cover-uncover, alternate cover test, Hirschberg test, Krimsky test and examination by synaptophore were done. Refraction and fundus examination was also done. Result: Majority of the patients were under 5 years of age (46.6%) with male to female ratio of 2:3. Convergent squint was more common (71.6%) with majority of patients having moderate degree of deviation (58.8%). Hypermteropia was more commonly associated with squint (65%) more so with convergent squint. Eccentric fixation was present in only 10% of the cases. Conclusion: Convergent concomitant squint is more common type with majority of patients having moderate degree of deviation. Hypermetropia is more commonly associated with concomitant squint. Appropriate refraction and timely intervention can help in preventing amblyopia in young children

The effectiveness of concomitant strabismus treatment in children with hyperopia by botulinum toxin type A chemodenervation

Purpose. Evaluation of the effectiveness of concomitant strabismus treatment in children with hyperopia by botulinum toxin type A chemodenervation. Materials and methods. The effectiveness of using botulinum toxin type A chemodenervation was studied in 115 children (230 eyes) from 8 months to 15 years old with concomitant convergent strabismus and hyperopic refraction. All patients were divided into 3 groups: group 1–17 patients with strabismus angle up to 15° according to Hirshberg, group 2–34 patients with strabismus angle from 15 to 25° according to Hirshberg, group 3–64 patients with strabismus angle more than 25° according to Hirshberg. All children received an injection of botulinum toxin type A into the horizontal oculomotor muscles at an average dosage of 3.4. Results. In most cases (68.70%), a positive effect was achieved after one injection. Two injections were given to 30 patients (26.09%), 6 patients were given 3 injections (5.22%). Repeated injections, most often (19.13%), were required in patients with a strabismus angle of more than 25 degrees. The effectiveness of strabismus treatment depends on the initial value of the angle and the adequately selected dose. Most often, a positive result of treatment was observed after one injection of botulinum toxin type A with a volume of 2 to 4. We did not find any complications when using the denervation method. Conclusion. The method of botulinum toxin type A chemodenervation is effective in the treatment of concomitant strabismus in children with hyperopia. Key words: botulinum toxin type A, concomitant strabismus, chemodenervation, children, hyperopia.