From the Guidelines
To forcibly deviate eye movements in a patient, a physician would typically use forced ductions, which confirm restriction, as part of a detailed sensorimotor evaluation, as recommended in the adult strabismus preferred practice pattern 1. This approach is crucial in assessing the oculomotor status, including possible ocular torsion impacting fusion. The examination should include a full sensorimotor examination, noting evidence of mechanical restriction, and may involve fixation duress, brow elevation, and augmentation of eyelid retraction on attempted ocular elevation, as outlined in the most recent guidelines 1. Some key points to consider when forcibly deviating eye movements include:
- Mechanical restriction can be determined at the time of surgery if in-office forced ductions are not possible 1
- The impact of mechanical restriction can be significant, and forced ductions can help determine its significance 1
- A detailed medical and ocular history, including specific questions about particular surgical procedures, anesthetic used, and onset of patient symptoms, should be obtained 1
- The examination should also include measurement of exophthalmos, surveillance for optic neuropathy, and monitoring of acuity, color vision, visual fields, pupillary examination, and fundus examination 1 By following these guidelines and using forced ductions as part of a comprehensive evaluation, physicians can effectively assess and manage adult strabismus, prioritizing morbidity, mortality, and quality of life as the primary outcomes.
From the Research
Forcible Deviation of Eye Movements
To forcibly deviate eye movements in a patient, a physician may use various methods, including:
- Prism and alternate cover test (PACT) 2
- Prism under cover test (PUCT) 3
- Automated video-oculography (VOG) system based on eye tracking and dedicated glasses 4
- Eye tracking systems to measure heterophoria 5
Methods for Measuring Deviation
The following methods can be used to measure deviation:
- Alternate cover test (ACT) 4
- Cover-uncover test 5
- Modified Thorington test 5
- Automated and objective cover test using an eye-tracker 5
Studies on Deviation Measurement
Studies have shown that:
- The prism and alternate cover test (PACT) has good interobserver reliability in children with esotropia 2
- The prism under cover test (PUCT) is a procedure with good repeatability and can be used to estimate manifest deviation when SPCT is not feasible 3
- Automated video-oculography (VOG) system based on eye tracking and dedicated glasses can provide objective and quantitative skew measurement 4
- Eye tracking systems can provide objective and more repeatable measures of heterophoria 5