Effect of using prismatic eye lenses on the posture of patients with adolescent idiopathic scoliosis measured by 3-D motion analysis

Abstract

This is a preliminary investigation to detect the body sway and postural changes of patients with AIS under different spatial images. Two pairs of low-power prismatic eye lenses (Fresnel prisms) with 5 dioptre and 10 dioptre were used. In the experiment, the apices of the prisms were orientated randomly at every 22.5° from 0° to 360° to test changes. Four patients with mean age of 11 and Cobb's angle of 30° were recruited and the results showed that the low-power prisms at specific orientations (157.5° and 180°) could cause positive postural changes (2.1° -2.7° reduction of angle of trunk mis-alignment) measured by 3-D motion analysis. This might be used for controlling their scoliotic curves by induced visual bio-feedback. Apart from this laboratory test, a longitudinal study is necessary to investigate the long-term effect of the prisms at different powers and orientations (under both static and dynamic situations) on the patient's posture, spinal muscular activities, vision, eyehand coordination, psychological state and other daily activities before it becomes an alternative management of AIS.

Negligible Impact on Posture From 5-Diopter Vertical Yoked Prisms

“…Our sample did not include people with postural abnormalities, and it could be argued that a significant impact on body posture may have been found in subjects with abnormal posture. For example, Wong et al 23 measured body posture in four young females with abnormal spine curvature, and found significant alterations in spine alignment after 3 minutes' wear with 10-D yoked prisms base up or base down, with opposite effects on the spine in the two different base directions. No significant effect was found with 5-D yoked prisms in any base direction, suggesting the possibility that stronger prism than the 5 D used in the present study may have yielded a significant impact on body posture.…”

A critical evaluation of the evidence supporting the practice of behavioural vision therapy

“…The approach advocated by Kraskin (described above) is to generate changes in posture that will impact upon visual status. Recently, there has been interest in the possibility that changes in visual input achieved through the use of yoked prisms can produce beneficial postural changes in adolescent patients with idiopathic scoliosis (Wong et al. , 2002).…”

Critical review on non-operative management of adolescent idiopathic scoliosis

“…This device is advised to be worn 23 hours a day. Wong et al (2002) used low-power prismatic eye lenses to create postural changes. This was a preliminary investigation to detect the body sway and postural changes of patients with AIS under different spatial images.…”