A Translucent Occluder for Studying Eye Position under Unilateral or Bilateral Cover Test

Abstract

A translucent occluder is presented through which the examiner may observe the patient's eyes but through which the patient sees only a vague glow. In the conventional cover test, we can observe, photograph and/or film the position and the movements of the eye under cover in strabismus and in nystagmus. In a simultaneous bilateral cover test, the patient has no structured vision. The Lancaster fixation-free static position (light tonus position) may be determined which may be orthophoria even in the case of a fusion-free basic deviation. A non-accommodative, non-fixation-linked deviation (Eso, Exo, or DVD) is then isolated which is interesting from both physiologic and therapeutic points of view.

• translucent occluder
• static fixation-free position
• basic fusion-free position
• simultaneous cover test
• Maddox vergences
• light vergence
• dark vergence
• esodeviation
• exodeviation
• DVD
• Bielchowsky phenomenon