Evidence on the parameters of oculomotor skills and normative values: A systematic review

To evaluate the current evidence on oculomotor measurement parameters and their normative values through a systematic review.

A search of primary studies was conducted using a search equation with free language. Original articles analyzing normal oculomotor function parameters in healthy populations of any age, studies that included a clearly differentiated healthy control group, and articles using any oculomotor measurement test were included. The QUADAS-2 tool was used to assess the risk of bias, applicability, and quality of the studies. The review was conducted independently by the authors and then pooled to determine the final inclusion.

A total of 915 articles were identified, of which 750 were excluded after the first review of the title and abstract. In the second step, 133 out of 165 investigations were discarded. Ultimately, 32 articles from the initial search were included, along with 10 additional articles identified through a manual search. The findings revealed variations in how oculomotor skills are measured, including differences in stimuli, measurement distances, and parameters assessed. A high risk of bias was observed (≥50 % in the areas of "flow and timing", "reference standard" and "patient selection") along with poor applicability (≥50 % in all aspects).

There is no clear evidence on normative values for oculomotor skills, nor is there a consensus on the measurement methods, stimulus used, or working distance. Furthermore, there is no agreement on which aspects of oculomotor skills should be assessed. To enhance reliability and applicability, measurement criteria should be standardized, and normative values should be established.