LACTOSE in Intermittent Exotropia
The New Castle score has been the standard system to evaluate the motor control in cases of intermittent exotropia. This consisted of a score for home control and office assessment. However there were few 
shortcomings for this system of scoring. An attempt to provide a new scoring system has been made recently and published as the LACTOSE score for intermittent exotropia. It stands for Look And Cover, then Ten seconds of Observation Scale for Exotropia (LACTOSE) and is based on the subjects potential to regain the phoria for both distance and near fixation. The test takes 1 minute to complete and is slated to be reliable and repeatable. The LACTOSE was created by incorporating both distance and near score (0-4 each) into a total score ranging from 0 to 8. Two hundred and thirty five consecutive patients with intermittent exotropia were prospectively evaluated using LACTOSE. Inter-rater reliability was found to be good for both distance and near and test-retest reliability was excellent. A broad representation of the total scores was significantly linked to the age of onset and the amount of exotropia. The new system may be adopted for assessment and research realted to intermittent exotropia.
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Kim H, Kim DH, Ahn H, Lim HT. Proposing a new scoring system in intermittent exotropia: towards a better assessment of control. Can J Ophthalmol. 2017 Jun; 52(3):235-239.