Efficacy and Safety of New Topical Sodium Pump Inhibitor (NSPI) in Reducing Eye Oscillations in A Canine model of Infantile Nystagmus Syndrome (INS)

Abstract

 

Purpose

 

To determine the ocular and systemic safety and efficacy of using a new topical medication in a canine model of INS. The rationale for this proposal is based on a case study of a patient whose INS improved after inadvertent exposure to a agent containing the NSPI.

 

Methods

 

After in vitro safety testing and IUCAC approval we studied increasing concentrations of topical NSPI drops (.002% to 0.7%) in canines with a purposely bred defect in the RPE65 gene resulting in both retinal degeneration and INS. We collected data on ocular and systemic effects and performed eye-movement recordings (EMR) using a remote video eye movement system with a protocol previously shown valid and reliable in canines.

 

Results

 

At the 0.7% concentration dose of NSPI there was minimal, reversible, conjunctival hyperemia. There was no other ocular or systemic toxicity. At the 0.6% dose there was a visible decrease in the INS and EMR showed a 150%-250% increase in NAFX and 30%-70% decrease (p<0.001) in amplitude across gaze. There was also a sustained (40%-60%) significant (p<.05) decrease in intraocular pressure from baseline.

 

Conclusions

 

This animal study suggests this new pharmacological agent has potential for topical treatment of both INS and diseases with raised intraocular pressure. Further, this new treatment approach confirms the importance of extraocular muscle proprioception in ocular motor diseases and their treatment.

 

 

CANINE DATA

 

Keywords: 619 nystagmus • 522 eye movements • 725 strabismus: treatment