Abstract
Introduction: :
A new computerised method of obtaining Hess Charts (Assaf Ocular Motility Analyser) has not yet been validated.
Purpose: :
To compare Hess Charts obtained using this computerised method against those obtained using the conventional Lees screen method.
Methods: :
65 consecutive patients aged >15 with ocular motility disorders participated in this prospective comparative study. Patients who had previously performed Hess Charts were excluded. Patients used both methods allocated in a random order. The vertical and horizontal components of the Hess scores for each eye with each method were used to calculate their correlation coefficients. The means and standard deviations of the differences between the methods were calculated. The 95% confidence intervals for the mean differences were found using the t–distribution.
Results: :
The mean patient age was 44.1 (range: 28 – 67). 39 of the patients were female. The correlation coefficients were 0.94 vertical, 0.94 horizontal left eyes, and 0.94 vertical, 0.95 horizontal right eyes. The standard deviations of the differences were 75.87 for vertical and 832.62 for horizontal components for left eyes, 75.10 for vertical and 128.11 for horizontal components for right eyes.
Conclusions: :
The scores obtained from both methods correlate positively, suggesting both methods can be used to assess Hess Charts qualitatively. The large standard deviations of the differences indicate that these two methods are not comparable. Without further studies, the computerised method is not suitable for assessing Hess Charts quantitatively.
Keywords: eye movements: recording techniques • strabismus: diagnosis and detection