|Title||WHICH METHOD OF FLICKER PERIMETRY IS MOST EFFECTIVE FOR DETECTION OF GLAUCOMATOUS VISUAL FIELD LOSS ?|
|Author, Co-Author||Kerri Yoshiyama, Chris Johnson|
Southern Hem IV
|Abstract|| PURPOSE. Flicker perimetry is an effective procedure for detection of glaucomatous damage, and is predictive of the onset of visual field deficits measured by conventional automated perimetry. However, two different procedures have been used to date. One method determines the Critical Flicker Frequency (CFF) for a high contrast flickering target while the other method, Temporal Modulation Perimetry (TMP), determines contrast modulation sensitivity for a target flickering at a fixed temporal frequency. The purpose of our study was to perform a direct comparison of the efficacy of these two methods of performing flicker perimetry.
METHOD. We performed test-retest measures of two methods of flicker perimetry (CFF and TMP) using a custom-designed flicker perimeter (100 cd/m2 background, 2 deg stimuli) that evaluated 44 locations (11 per quadrant) throughout the central 30 deg radius of the visual field. CFF measured the highest temporal frequency for detecting flicker of a target modulated at 98% contrast. TMP measured the threshold contrast modulation for detecting flicker of a target with a temporal frequency of 8 Hz. A modified binary search staircase procedure was used for both flicker tests. Sixteen patients with early to moderate glaucomatous visual field loss and sixteen age-matched normal control subjects were evaluated.
RESULTS. The coefficient of variation for test-retest measures of CFF and TMP was similar in both the normal control and glaucoma patient populations. However, TMP revealed more extensive deficits than CFF in the glaucoma patients as compared to the normal controls. TMP measures were able to produce a greater separation of the normal control and glaucoma patient populations.
CONCLUSION. Although both test procedures have similar test-retest reliability, TMP appears to be a more sensitive procedure than CFF for detection of early glaucomatous visual field loss. The basis for differences in the effectiveness of TMP and CFF will be discussed.
|Affiliation of Co-Authors|