Purpose:
(i) To establish an appropriate examination procedure for monitoring advanced glaucomatous visual field defects using SKP and (ii) to evaluate retest–reliability over a period of 9 months (4 sessions).
Methods:
In a prospective study 20 eyes of 20 patients (11 male, 9 female; aged 38 to 83 yrs.) with advanced visual field loss (Aulhorn stage III or IV) were examined in 4 sessions every 3 months with SKP (Goldmann stimulus III4e within the 90° visual field) and static automated perimetry (SAP) within the 30° visual field, using a threshold–related, slightly supra–luminal strategy with high spatial resolution. Differences in central 30° intact visual field area (VFA) of SKP and SAP was compared by ratios of intersection and union of VFA. Median and 95% reference intervals (RI) were estimated, the latter by third largest and third smallest of 80 values. Similarly, intraindividual ratios of intersection and union of baseline and follow–up VFA are given as a reference. VFA change was estimated in analyses of variance with covariable time, patient effects, and the interaction. Mean slope and residual standard deviation (s) were divided by the mean VFA.
Patients were asked which of the two methods they would prefer.
Results:
Within 30° eccentricity the results of SKP and SAP from the same session showed comparable VFA. The median of the ratio of intersection and union areas was 78% (RI 48% to 95%). During the course of the study the patients showed stable visual fields both for the SKP and the SAP examination:
18/20 patients reported that they would prefer kinetic perimetry to static perimetry.
Conclusions:
SKP shows slightly better retest reliability as SAP, comparable VFA and VFA trend. The majority of patients with advanced glaucomatous visual field loss preferred SKP. Thus SKP is a valuable alternative to SAP in monitoring advanced glaucomatous visual field loss.
Keywords: visual fields • perimetry