Vijay Chopra, Pramila Balasubramanian

Malalignment in the visual axes of the two eyes is called strabismus. Fusion of both images is replaced either by diplopia or suppression of one image. Squint leads to loss of binocular single vision. Concomitant squint is a type of manifest squint in which the amount of deviation in the squinting eye is same in all gazes. Binocular single vision and ocular movement coordination are not present since birth, but are acquired in the early childhood. This process starts by the age of 3-6 months and is completed up to 5-6 years. Any hindrance in the development of these processes may result in concomitant squint.

In 100 cases of concomitant squint, patients were included in our study. Detailed history was taken regarding the onset of squint and duration. Past history and family history was also elicited. General examination was done to detect any abnormalities of central nervous system. Routine ophthalmic examination including best corrected visual acuity, cover test performed to detect the type of deviation whether uniocular or alternating and the type of fixation. Angle of deviation was measured by Hirschberg’s test and on the synoptophore. Binocular single vision was assessed using Worth’s 4-dot test and synoptophore. Cycloplegic refraction and fundus evaluation done in all patients. Inclusion Criteria- All primary non-paralytic deviations, sensory deprivation strabismus. Exclusion Criteria- Paralytic strabismus, strabismus associated with neurological disorders, consecutive strabismus and palpebral fissure abnormalities patients.

Majority of cases of concomitant squint were of esotropic type. Most common form of esotropia seen was infantile esotropia. Most common form of exotropia was intermittent exotropia. 19% of cases were secondary to other ocular diseases namely cataract, macular lesion, high myopia, etc. Amblyopia was present in 54% patients and of very dense type, which could not be treated effectively as patients presented themselves late. Degree of deviation in range of 10-20 degrees is commonly seen in both esotropia and exotropia. Hypermetropia constituted most common refractive error in our study.

This study is conducted to spread awareness and education regarding concomitant squint and its effect on vision and need for early detection and treatment to prevent loss of sight and loss of binocular vision. Mass screening programmes should be conducted to detect concomitant squint early and treat it. Parents and teachers should be informed of importance of squinting eye and in availing early investigation of its causes and treating it.