We measured the ability to fuse dichoptic images of a horizontal line alone or in the presence of a textured background with different vertical disparity. Nonius-line measurements of vertical vergence were also obtained. Diplopia thresholds and vertical vergence gains were much higher in response to an isolated vertically disparate line than to one with a zero vertical-disparity background. The...

PURPOSE To compare base-in prism reading glasses with placebo reading glasses for the treatment of symptomatic convergence insufficiency (CI) in children aged 9 to <18 years. METHODS In a randomised clinical trial, 72 children aged 9 to <18 years with symptomatic CI were assigned to either base-in prism glasses or placebo reading glasses. Symptom level, measured with a quantitative symptom qu...

INTRODUCTION Orthoptic exercises have been the primary treatment for convergence insufficiency since this condition's first description in 1855. It is presumed that exercises work by improving fusional convergence. In recent years, research from eye movement laboratories has challenged our theories on the nature and dynamics of convergence, the effect of convergence exercises, and the etiology ...

Types of Convergence (1) Voluntary Convergence – Amount of Convergence of visual axes that can be produced at will (2) Reflex convergence Convergence of visual axes which is not under complete voluntary control and it has four components – a. Tonic convergence – Due to inherent innervational tone of extra ocular muscles. b. Fusional convergence -The convergence that is produced to ensure that s...

Monkeys generated disjunctive smooth pursuit eye movements when they tracked visual targets that moved toward or away from them. Eye acceleration was computed during the initial 100 msec of pursuit (the open-loop interval) for various target trajectories. The initial acceleration of either eye was a function of the target's motion with respect to that eye, regardless of whether or not the pursu...

Acquired central disruption of fusional amplitude is characterized by a complete loss of fusional amplitude, the patient maintaining fusion for only a moment under test conditions before breaking to constant diplopia. Under normal viewing conditions, the patient has constant diplopia with both eyes open. Patients who have bilateral superior oblique palsy may mimic this loss of fusion and consta...