Objective: To develop a bioadhesive phosphorescent particle that can be used as a marker in video-oculography to assess eye movements in the dark without drug treatment.
Methods: The marker was prepared by spray-coating a Sr4Al14O25: Eu2+, Dy3+ phosphor with a carboxyvinyl polymer. The morphologic, luminescent and adhesive properties were assessed. The dynamic properties of VOR measured by the marker were compared with those obtained by tracking the pupil under miotic treatment.
Results: Non-aggregated and non-fused particles having diameters of about 5µm could be prepared by polymeric coating of the phosphor, resulting in particles small enough not to restrict eye movement. Although the phosphorescent of the particles decreased with increasing thickness of the coating layer, the coated particles were detectable in the dark for at least 60 min. The thicker the coating layer was, the higher the adhesiveness of the particles obtained. The particles having the thickest coating layer were retained on the corneal surface during VOR measurement and thus performed well as a marker in video-oculography. The dynamic properties of VOR measured by the marker were essentially identical to those obtained by tracking the pupil under miotic treatment.
Conclusion: Our marker will contribute to understanding the mechanisms underlying motor learning.