Correlations between intermittent exotropia, stereoacuity and ocular torsion

Aims: To objectively measure anatomical ocular torsion in intermittent exotropia (IXT), correlate with the amount of exo-deviation and stereoacuity Methods: We enrolled 84 participants from 8 to 35 years. Revised Newcastle control scores were obtained. Deviation was measured using prism cover test. Titmus stereo test was used for stereopsis. Dominant eye was identified using a hole in the card test. Anatomical Ocular torsion was obtained using Spectralis SD-OCT. Any sorts of pathological conditions affecting ocular motility were excluded. Results: The anatomical torsion of left or right eyes or their relative difference among different IXT groups was not found statistically significant (p-value >0.05). Newcastle Control Scale score was lowest 1 (1-2) in the convergence insufficiency group, 4 (2-8) in the divergence excess group and highest 5 (3-6) in the basic group (p-value <0.000). The amount of exodeviation positively correlated with different Newcastle Control Scales scores but no correlations were found between anatomical ocular torsion and neither stereopsis, nor the amount of near and distance exo-deviations. Conclusion: This study could not establish significant correlations between anatomical ocular torsion measured objectively with OCT and the severity of deviation or stereoacuity. The revised Newcastle Control Scale was remarkable in monitoring the progression of IXT.