Related Experiment Video
Updated: Jun 12, 2026

Assessing Early Stage Open-Angle Glaucoma in Patients by Isolated-Check Visual Evoked Potential
Published on: May 25, 2020
Fusional vergence measures and their significance in clinical assessment
1Directorate of Orthoptics and Vision Science, University of Liverpool, UK. rowef@liverpool.ac.uk
Purpose:
The aims of this study have been to evaluate differences between ranges in eso or exo deviances and with varying target size.
Methods:
Evaluation of sensory status in compensated deviations included measures of fusional vergence (blur, break and recovery values) with randomization of target size and order of prism base. Angle of deviation measures were assessed for each case.
Results:
Twenty-two subjects, 7 esophoric and 15 exophoric, were recruited. Median prism fusional vergence range at near fixation was 25BO to 10BI (central target); 35BO to 12BI (peripheral target). At distance fixation median range was 16BO to 6BI (central); 25BO to 6BI (peripheral). Esophorics had a range shift towards the base out range. Exophorics had a shift towards the base in range.
Conclusions:
Smaller positive fusional vergence values were obtained with small compared with large target sizes. Additionally, esophoric subjects had a trend towards larger base out ranges while exophoric subjects had a trend towards larger base in ranges.
Related Concept Videos
Association Areas of the Cortex
Prefrontal Association Area: This area is located in the frontal lobe and is involved in planning, decision-making, and moderating social behavior. It connects with primary motor areas,...
Angle Closure Glaucoma: Treatment
Glaucoma: Overview
Depth Perception and Spatial Vision
Focusing of Light in the Eye
Open Angle Glaucoma: Treatment
Drugs such as carbonic anhydrase inhibitors, α2- and...
