Search

The study aims to determine the prevalence of strabismus and its risk factors among school children in Hong Kong. This is a cross-sectional study involving 6-8 year old children from different districts in Hong Kong. 4273 children received comprehensive ophthalmological examination, cycloplegic auto-refraction, best corrected visual acuity (BCVA), anterior segment examination, cover/uncover test, ocular motility, and fundus examination. Demographic information, pre- and post- natal background, parental smoking status, and family history of strabismus were obtained through questionnaires. Strabismus was found among 133 children (3.11%, 95% CI 2.59-3.63%), including 117 (2.74%) exotropia and 12 (0.28%) esotropia cases (exotropia-esotropia ratio: 9.75:1). There was no significant difference in prevalence across age (6-8 years) and gender. Multivariate analysis revealed associations of strabismus with myopia (≤ - 1.00D; OR 1.61; 95% CI 1.03-2.52; P = 0.037) hyperopia (≥ + 2.00D; OR 2.49; 95% CI 1.42-4.39; P = 0.002), astigmatism (≥ + 2.00D; OR 2.32; 95% CI 1.36-3.94; P = 0.002), and anisometropia (≥ 2.00D; OR 3.21; 95% CI 1.36-7.55; P = 0.008). Other risk factors for strabismus included maternal smoking during pregnancy (OR 4.21; 95% CI 1.80-9.81; P = 0.001), family history of strabismus (OR 6.36; 95% CI 2.78-14.50, P < 0.0001) and advanced maternal age at childbirth (> 35 years; OR 1.65; CI 1.09-2.49, P = 0.018). The prevalence of strabismus among children aged 6-8 years in Hong Kong is 3.11%. Refractive errors, family history of strabismus and maternal smoking history during pregnancy are risk factors. Early correction of refractive errors and avoidance of maternal smoking during pregnancy are potentially helpful in preventing strabismus.

Purpose: The management of A or V pattern deviation associated with esotropia can be challenging since the horizontal deviation changes with position of gaze. This study aimed to assess the effect of unilateral horizontal rectus surgery for the correction of horizontal deviation associated with A or V pattern in children with non-comitant infantile esotropia., Methods: Twenty-seven children with infantile esotropia and A-V pattern, more than 10 and 15 prism diopters respectively, were included in this retrospective observational single-center study. Horizontal rectus surgery was performed on the most deviated eye under general anesthesia. The patients were divided into two groups: A pattern and V pattern. The outcome measures were change in the amount of pattern and rate of regression after surgery. The amount of pattern was characterized by the difference in esodeviation between upgaze and downgaze., Results: Horizontal deviation at distance and near fixation decreased significantly (P<0.0001). Vertical gaze esotropia disparity decreased significantly (P=0.01 and P=0.0002 for A and V patterns respectively). A pattern esotropia was reported in only 2 (7%) cases after surgery compared to 9 (33%) before surgery. The number of subjects with V pattern esotropia decreased from 18 (67%) to 3 (11%) after surgery., Conclusions: The mechanisms involved in the pathophysiology of A and V patterns may not always be related to oblique muscle dysfunction. These findings suggest that unilateral horizontal rectus surgery may be an effective procedure to correct both horizontal deviation and A-V pattern in non-comitant infantile esotropia., (Copyright © 2019 Elsevier Masson SAS. All rights reserved.)

Introduction: Acute acquired distance esotropia (AADE) is a poorly understood moderate-angle strabismus, affecting young adult myopes and determining bothersome diplopia. Symptoms can be intermittent in the early stages, becoming constant in long-lasting disease. Symptomatic therapy includes prism correction, while surgery is the only curative treatment. However, the latter is affected by high rate of symptoms recurrence with the frequent need for reoperation., Hypothesis: We hypothesize that AADE could be caused by the increase of the accommodative demand, often secondary to a myopic overcorrection. This condition could determine an increase in induced hyperopia at near, dominated by an excess of accommodation and therefore of convergence. The latter cannot be relaxed at distance and diplopia develops. We speculate that early-stage AADE could be successfully treated by cycloplegic eye drops slowly tapered within three months. On the other hand, surgery remains the only option in long-lasting AADE. In these cases, we propose a new pre-operative assessment of esotropia by asking the patient to fix alternatively a stimulus at near and at distance in order to stimulate the accommodative convergence. This technique allows to unmask the total amount of the angle of deviation and to plan a wider bilateral medial rectus muscle recession avoiding long-term residual esotropia., Discussion: Currently, AADE curative therapy is surgical regardless of onset time but it is usually affected by poor outcomes. If our hypothesis was to be confirmed, pharmacological treatment could solve early-stage AADE, avoiding any surgery. Furthermore, a wide bilateral medial rectus muscle recession, quantified on the basis of the above mentioned test for measuring the total amount of the strabismus angle, could improve outcomes eliminating the need for reoperation in long-lasting AADE., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Purpose: To identify strabismus-related proteins, we performed proteome analysis in monozygotic twins with discordance of congenital esotropic phenotypes and in normal children., Methods: Surface-enhanced laser desorption/ ionization time-of-flight mass spectrometry (SELDI-TOF-MS) technology was used to detect changes in protein expression in a pair of twins with discordant esotropic phenotypes (twin A is orthotropic and twin B is esotropic). In addition, two non-twin esotropic children and two orthotropic children of the same age were chosen. The differentially expressed proteome obtained was validated in twelve non-twin esotropic children and eighteen orthotropic children and compared to the protein database., Results: We detected four differentially expressed proteins in monozygotic twins with discordance of congenital esotropic phenotypes. The corresponding molecular weights were 4,146 Da, 4,801 Da, 7,786 Da, and 5,859 Da, respectively. Among these 4 proteins, the first three proteins were down-regulated and the last was upregulated. The initial characterization of these detected proteins via protein library revealed that their characteristics were similar to those of the glucagon precursor, pituitary adenylate cyclase-activating polypeptide (PACAP), camp-dependent protein kinase inhibitor α, and anti-metastasis gene (antigen), respectively., Conclusions: There were differentially expressed proteins between monozygotic twins with discordance of congenital esotropic phenotypes and normal children. These differentially expressed proteins were mainly down-regulated in the strabismus patients and may be involved in the occurrence and development of congenital esotropia.

The connectivity of the corpus callosum in visual cortical areas 17 and 18 was studied in normal cats, in cats reared with unilateral convergent or divergent surgically-induced strabismus, and in a Siamese cat. The extents of the callosal cell and terminal zones were determined following multiple injections of horseradish peroxidase and tritiated amino-acids into one hemisphere. Following surgically-induced strabismus, abnormally wide callosal cell zones were seen in both the left and the right hemisphere irrespective of the direction of eye misalignment. Abnormally wide callosal terminal zones were seen in the hemisphere ipsilateral to the deviating eye in cats reared with unilateral convergent and divergent strabismus. Abnormally wide callosal zones were seen in cats which had strabismus induced as late as postnatal day 36. In a Siamese cat with a naturally-occurring convergent strabismus, callosal cells had a different distribution and were fewer in number compared to normal cats or cats with surgically induced strabismus. This implies that the abnormal callosal connectivity of Siamese cats is not a simple result of strabismus.

Three men developed acute esotropia, stupor, and impaired upward gaze. Vestibulo-ocular stimulation showed that the adducted eye remained immobile while the fellow eye responded normally. The alteration of consciousness, the long-tract neurologic signs, and the esotropia quickly resolved. Upgaze paresis and brief bursts of convergence-retraction nystagmus were the major residual signs. Imaging techniques demonstrated lesions of the contralateral posterior thalamus in each patient. Several mechanisms are proposed to explain the acute esotropia. Impairment of monocular projections in the contralateral posterior thalamus could disinhibit neurons in the oculomotor complex, or ischemia of inputs to neurons involved with vergence control in the midbrain could result in tonic activation of the medial rectus. The clinical and radiographic findings are consistent with infarction in the territory of penetrating branches of the basilar-communicating (mesencephalic) artery. Embolism to the top of the basilar artery is presumed to be the precipitating event.