By Jamie Chang, Yong Loo Lin School of Medicine, National University of Singapore
Ms Lim Mun Ching, Optometrist at Singapore National Eye Centre, gave a lecture on “Identifying and Managing Binocular Vision Anomalies” during the Singapore Primary Eye Care Symposium (SPECS) 2019 between 23-24 July 2019 at One Farrer Hotel, Singapore.
Binocular single vision is a sensorimotor process and a state of simultaneous vision which is achieved by the coordinated use of both eyes, so that separate and slightly dissimilar images arising in each eye are appreciated as a single image by the process of fusion. However, when binocular single vision becomes anomalous, images of the fixated object are projected from the fovea of one eye and an extrafoveal area of the other eye i.e., when the visual direction of the retinal elements has changed. A small manifest strabismus is therefore always present in anomalous binocular single vision.
This is very important for single vision and stereopsis, the most precise kind of depth perception. Ms Lim also mentioned how crucial it is for practitioners to accurately diagnose a patient suffering from any anomalies of binocular single vision early so that it can be effectively managed before the symptoms worsen further.
Ms Lim emphasized the importance of accurate differential diagnosis through the many cases presented during the lecture. Some of the cases included patients showing symptoms of refractive (accommodative) esotropia and dissociated vertical deviation (DVD), where one eye shifts upwards and extorts when the two eyes are not working together. She also mentioned some possible treatment and management plans such as monitoring the changes in the binocular vision status and changes in the prescription. Urgent cases which are to be dealt with promptly include patients who present with recent or a sudden onset of diplopia or squinting and the worsening of the diplopia and its symptoms.
People depend significantly on binocular single vision to carry out their day to day activities. Hence, it is important to maintain this ability through diligent diagnoses, treatment and management plans.