Digitalized Videographic Measurement of Strabismic Angle

ABSTRACT

Current using strabismic angle measurement techniques require examiners experience and subjective decision. The accuracy between observers and intra-observer is limited by the minimum eye movement that the examiner can detect with naked eye. Horizontal strabismic angles with 35 comitant strabismus patients were measured using precise digital signals converted by digital frame grabber and image processing software in a 32 bit microcomputer. Strabismic angle calculated using digital method was compared with that of prism-cover method. The slope of the regression line was 1.1054; the Y-intercept was 1.3870PD. The coefficiency of variation to verify its reproducibility for measurements of total variability in 35 strabismic patients was 3.71%. The strabismic angle measurement with digital frame grabber seems to be relatively precise and clinical application will be available in measuring horizontal and vertical strabismic angel.