purpose: the goal of this study was to compare differences in the mean heterophoria and fusional amplitudes before and after photorefractive keratectomy (prk) for myopia. methods: in a prospective controlled study, myopic patients were treated with aspheric and wavefront-guided (personalized) prk. the manifest refraction, visual acuity, fusional amplitudes and heterophoria were evaluated preope...

PURPOSE To examine accommodation and accommodative convergence relationships in naturally strabismic monkeys. METHODS Photorefraction was used to measure accommodative responses of each eye under monocular and binocular viewing conditions. These accommodative results were then compared to assessments of vergence state made under monocular viewing conditions using methods previously described....

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 ...

Great discrepancies are often encountered between the distance fixation and the near-fixation esodeviations and exodeviations. They are all attributed to either anomalies of the AC/A ratio or anomalies of the fusional convergence or divergence amplitudes. We report a case with pseudoconvergence insufficiency and another one with pseudoaccommodative convergence excess. In both cases, conv./div. ...

PURPOSE Clinical studies have shown that positive fusional vergence (PFV) can be trained through a program of orthoptic exercises. Models of accommodation and vergence predict that training PFV would require a reduction in the convergence accommodation (CA) cross-link. Recent investigations have found that the CA/C ratio is not changed in a clinical population after orthoptics. We hypothesized ...

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...

This study evaluated changes in phoria and negative (NFV) positive fusional vergence (PFV) when wearing a cap and/or goggles. Thirty-five healthy university students aged 20–25 years participated the study. All participants were examined for phoria, NFV, PFV at distance near. A rotary prism was used before after cap, goggles, both The frequency of overall average change swimming equipment compa...