Video 4.3 Evaluating convergence from Neuro-Ophthalmology and Neuro-Otology Textbook
Creator
Tony Brune, DO; Daniel R. Gold, DO
Affiliation
(TB) Department of Neurology, The Johns Hopkins School of Medicine, Baltimore, Maryland; (DRG) Departments of Neurology, Ophthalmology, Neurosurgery, Otolaryngology - Head & Neck Surgery, Emergency Medicine, and Medicine, The Johns Hopkins School of Medicine, Baltimore, Maryland
Subject
Normal Convergence
Description
𝗢𝗿𝗶𝗴𝗶𝗻𝗮𝗹 𝗗𝗲𝘀𝗰𝗿𝗶𝗽𝘁𝗶𝗼𝗻: The assessment of convergence includes measuring alignment at near versus distance (see video, https://collections.lib.utah.edu/details?id=187677), near point of convergence and convergence amplitude. Near point of convergence is assessed by bringing a fixation target toward the bridge of the patient's nose. The distance at which binocular fixation is lost or diplopia is experienced is recorded (also see video, https://collections.lib.utah.edu/details?id=187671). Convergence amplitude is determined by placing base out prisms of increasing power over one eye while the patient views a near target. The highest prism power before binocular fixation is lost or diplopia is experienced is the convergence amplitude. Although the specific diagnostic criteria for convergence insufficiency may differ, typically the diagnosis is made when: 1) the near point of convergence is greater than 10 centimeters, 2) the convergence amplitude is less than 15 prism diopters, and 3) there is an exodeviation greater than 10 PD at near, or the exodeviation at near is at least four prism diopters greater than what is recorded at distance. 𝗡𝗲𝘂𝗿𝗼-𝗼𝗽𝗵𝘁𝗵𝗮𝗹𝗺𝗼𝗹𝗼𝗴𝘆 𝗮𝗻𝗱 𝗡𝗲𝘂𝗿𝗼-𝗼𝘁𝗼𝗹𝗼𝗴𝘆 𝗧𝗲𝘅𝘁𝗯𝗼𝗼𝗸 𝗟𝗲𝗴𝗲𝗻𝗱: The assessment of convergence includes measuring alignment at near versus distance, near point of convergence and convergence amplitude. Near point of convergence is assessed by bringing a fxation target toward the bridge of the patient's nose. The distance at which binocular fxation is lost or diplopia is experienced is recorded. Convergence amplitude is determined by placing base out prisms of increasing power over one eye while the patient views a near target. The highest prism power before binocular fxation is lost or diplopia is experienced is the convergence amplitude. Although the specifc diagnostic criteria for convergence insuffciency may differ, typically the diagnosis is made when: 1) the near point of convergence is greater than 10 centimeters, 2) the convergence amplitude is less than 15 prism diopters, and 3) there is an exodeviation greater than 10 PD at near, or the exodeviation at near is at least four prism diopters greater than what is recorded at distance. (Video and legend created with the assistance of Dr. Tony Brune and Justin Bosley) https://collections.lib.utah.edu/ark:/87278/ s6zd22m0