Related Experiment Video
Updated: Feb 6, 2026

Providing Visual Biofeedback Using Brightness Mode Ultrasound During a Golf Swing
Published on: August 25, 2022
Objective assessment of a relative afferent pupillary defect by B-mode ultrasound
Felix A Schmidt1,2,3, Florian Connolly1, Matthew B Maas4
1Department of Neurology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Neurocure Cluster of Excellence, Berlin, Germany.
Purpose:
To evaluate B-mode ultrasound as a novel method for objective and quantitative assessment of a relative afferent pupillary defect (RAPD) in a prospective case-control study.
Methods:
Seventeen patients with unilateral optic neuropathy and a clinically detectable RAPD and 17 age and sex matched healthy controls were examined with B-mode ultrasound using an Esaote-Mylab25 system according to current guidelines for orbital insonation. The swinging flashlight test was performed during ultrasound assessment with a standardized light stimulus using a penlight.
Results:
B-mode ultrasound RAPD examination was doable in approximately 5 minutes only and was well tolerated by all participants. Compared to the unaffected contralateral eyes, eyes with RAPD showed lower absolute constriction amplitude of the pupillary diameter (mean [SD] 0.8 [0.4] vs. 2.1 [0.4] mm; p = 0.009) and a longer pupillary constriction time after ipsilateral light stimulus (mean [SD] 1240 [180] vs. 710 [200] ms; p = 0.008). In eyes affected by RAPD, visual acuity correlated with the absolute constriction amplitude (r = 0.75, p = 0.001).
Conclusions:
B-mode ultrasound enables fast, easy and objective quantification of a RAPD and can thus be applied in clinical practice to document a RAPD.
Related Concept Videos
What is a Mode?
There can be more than one mode in a data set if multiple values have the same highest frequency. For instance, suppose that the Statistics exam scores of 20 students are: 50; 53; 59; 59; 63; 63; 72; 72; 72; 72; 72; 76; 78; 81; 83; 84; 84; 84; 90; 93. Here, the mode is 72, as it occurs most frequently, five times.
A data set with two modes is called bimodal. For example,...
Assessing Blood pressure using a doppler ultrasound
Pre-Procedural Guidelines for Doppler Ultrasound Blood Pressure Assessment:
Preparation of Equipment:
Ventilatory Modes
There are three ventilatory modes: full support, partial support, and spontaneous. These are described below.
Full Support Modes
Full support modes include controlled mechanical ventilation, continuous mandatory...
Lumber Defects
Shakes are minor fractures that run along or across the wood's annual rings, while wane is...
Velocity of an Object
Modes of Standing Waves - I

