Eye Tracking Software Can Objectively Quantify Infantile Nystagmus Deviations

Eye tracking may be an inexpensive and objective approach for monitoring infantile nystagmus, according to research published in the Journal of Optometry.

Researchers included 3 children (age range, 6-7 years) and 1 adult (age, 48 years) with infantile nystagmus and 9 control group participants (age range, 6-7 years) in the prospective, observational pilot study. The participants performed a reading task while researchers measured the speed of eye movements and variations in gaze trajectory using recordings displayed on a 15 inch monitor. 

The control group participants demonstrated little fluctuation in vertical eye positions, with eyes moving from left to right, consistent with reading the text line-by-line. The participants with nystagmus, however, showed movements with many fluctuations, both with and without foveations. Eye movements among the control group were significantly slower than those observed in the group with nystagmus — 85% of control group participants demonstrated speeds of 0.33 cycles per second or slower, while only 16% of individuals with nystagmus had eye movement speeds within this range. The 85th percentile for individuals with nystagmus included values ranging from 0 to 2.43 cycles per second, according to the report. 

The difference in the speed of movements indicated that control group participants spent most of their time fixating on the text. Patients with nystagmus spent less time reading than individuals in the control group (P =.73), demonstrating significantly faster eye movement speed (P =.01) and more time fluctuating their gaze (P =.01).

“Eye tracking is a powerful technology to register eye movements non-invasively while the subject being evaluated performs a visual task,” according to the researchers. “The method developed in this study could be appropriate to be used in clinical practice, since it would allow an objective evaluation of the effect of treatment in patients and facilitate the comparison of different treatments in randomized, blinded clinical trials.” 

Study limitations include a small sample size and the potential for volunteer bias.