The use of semi-automated kinetic perimetry (SKP) to monitor advanced glaucomatous visual field loss

Abstract

(i) To compare visual field (VF) results obtained with semi-automated kinetic perimetry (SKP) and automated static perimetry (ASP) in patients with advanced glaucomatous VF loss, (ii) to evaluate test-retest reliability of SKP and ASP and (iii) to assess patients' preference for SKP and ASP. Twenty eyes of 20 patients (11 male, 9 female, aged 38 to 83 years) with advanced glaucomatous VF loss (stage III or IV according to the Aulhorn classification). Each of the 20 patients were examined in 4 sessions every 3 months with SKP (Goldmann stimulus III4e, I4e and at least one additional dimmer stimulus, within the 90 degrees visual field) and ASP within the 30 degrees VF, employing a threshold-related, supra-threshold test strategy with high spatial resolution for the same instrument (Octopus 101 perimeter, Haag-Streit Inc., Koeniz, Switzerland). Visual field areas (VFA) were compared by analyses of covariance (ANCOVA) with co-variable time, patient effect and their interaction. Test-retest reliability was assessed by ratios (R) of intersection and union of VFA: The mean VFA within the 30 degrees of VF at baseline was 2,344 square degrees (deg(2)) with SKP (Goldmann stimulus III4e) and 1,844 deg(2) with ASP. The patients showed stable visual fields for both SKP and ASP. Comparison of SKP with ASP of the same sessions revealed a median ratio of intersection and union of VFA of 0.78 with the III4e stimulus and of 0.79 with the I4e stimulus. When follow-up SKPs were compared with baseline SKPs the median of the ratios was between 0.80 and 0.93 for the different isopters. The corresponding ratio of ASP's follow-up and baseline VFs was 0.81 (with the size III static stimulus). Nineteen of 20 patients preferred kinetic perimetry to static perimetry. The comparability between SKP and ASP is satisfactory and within the range of the test-retest reliability of ASP. SKP shows slightly better test-retest reliability than ASP. The majority of patients with advanced glaucomatous visual field loss prefer SKP instead of ASP. SKP is a valuable alternative to ASP in monitoring advanced glaucomatous visual field loss.