In order to see objects clearly, our eyes need to be able to work together by superimposing the images perceived by each eye: by rotating inwards (convergence) when the object is close, and by releasing this convergence when switching to object farther away. This ability of our eyes to perform symmetrical and coordinated movements (at the same speed and amplitude) is called binocular vergence. Vergence disorders or orthoptic disorders are therefore characterized by poor coordination of the two eyes. In children, these can generate incapacitating symptoms (dizziness, instability, difficulty reading, etc.) which can be responsible for school absenteeism and learning difficulties.
A team of researchers led by Sylvette R. Wiener-Vacher (AP-HP practitioner) and Maria Pia Bucci (CNRS researcher) in Unit 1141 NeuroDiderot: Neurodevelopmental and neurovascular diseases (Inserm/Université de Paris), had previously shown that children presenting with dizziness and normal neurological and vestibular[1] examinations should be screened for vergence disorders. Their latest research, published in Frontiers in Integrative Neuroscience, shows that dizziness linked to vergence disorders in children could be treated by a combination of orthoptic training and reduced screen time.
Over a 3-year period, the research team evaluated the efficacy of orthoptic training in children referred to the ENT Department of Robert-Debré hospital – AP-HP for dizziness. Forty-nine children presenting with vergence insufficiency as sole cause of their symptoms were enrolled in this study, along with 109 healthy control children. Each child was followed up for 9 months and underwent orthoptic evaluation (vergence capacity tests) as well as recordings of the eye movements at various stages of the study: before and 3 months after the start of orthoptic training, and 6 months after the end of the training. The researchers also advised all children to reduce their use of video screens which was intensive (~ 3.6 h per day) and which appeared as a potential aggravating factor.
In all patients, the dizziness disappeared after the end of the orthoptic training and all eye movement parameters improved significantly. Six months after the end of the training, this improvement remained stable or continued.
The results of this study also suggest that intensive screen use can aggravate pre-existing latent orthoptic problems, with the researchers specifying that “Today many children are exposed to small video screens for long periods of time. The increasing prevalence of symptomatic vergence insufficiency that we observed could be explained by this lifestyle. ” The authors recommend the inclusion of orthoptic training in clinical tests for children suffering from dizziness as well as reduced exposure to video screens, particularly for children presenting vergence disorders.
[1] The vestibule is part of the inner ear which is involved in maintaining balance.
Maria Pia Bucci
Unit Inserm 1141 NeuroDiderot: Neurodevelopmental and neurovascular diseases
Glial homeostasis, neuroinflammation and neuroprotection (neurokines)
+33 (0)1 40 03 53 62
Sylvette Wiener-Vacher
presse@inserm.fr
Dizziness and Convergence Insufficiency in Children: Screening and Management
Sylvette R. Wiener-Vacher1,2*, Sidney I. Wiener3, Layla Ajrezo1, Rima Obeid1, Damir Mohamed4, Priscilla Boizeau4, Corinne Alberti4,5 and Maria Pia Bucci1,2
1 Pediatric Balance Evaluation Center (EFEE), ENT Department, AP-HP, Hôpital Robert Debré, Université de Paris, Paris, France
2 Hopital Robert Debré, UMR1141 Inserm-Université de Paris, Paris, France
3 Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS, Inserm, PSL Research University, Paris, France
4 Clinical Epidemiology Unit, AP-HP, Hôpital Robert Debré, Paris, France
5 UMR-S 1123, CIC-EC 1426, Inserm, Université de Paris, Paris, France
Frontiers in Integrative Neuroscience : https://doi.org/10.3389/fnint.2019.00025
