Applicability of semi-automated kinetic perimetry (SKP) in the assessment of the visual field loss due to retinitis pigmentosa

Objective: To assess the applicability of a new technique of kinetic visual field examination--semi-automated kinetic perimetry (SKP)--in patients suffering from the visual field defects due to retinitis pigmentosa.

Methods: Thirty-five patients (19 women, 16 men: mean age 38.4 years) suffering from retinitis pigmentosa (10 with with Usher syndrome, one with Bardet-Biedl syndrome and one with Refsum syndrome) were examined using SKP software, implemented in Octopus 101 instrument (Haag-Streit, Koeniz, Switzerland). Three stimuli (1114e and 14e obligatory) were used to assess the hill of vision of each patient. The area of each isopter was measured in deg2. The test time was measured automatically in minutes.

Results: The visual field results were classified as complete or incomplete midperipheral "ring scotoma" (group I--13 patients) and concentric loss of the visual field (group II--22 patients). The area of 1114e isopter was 6147.5 deg2 in the group I and 1961.7 deg2 in the group II. The area of 14e isopter was 1468.4 deg2 and 781.7 deg2, respectively. The mean test time was 10 min. (range 4-20 min.): 8 min. in the group I and 13 min. in the group II.

Conclusions: There is a large diversity of patterns of the visual field loss in retinitis pigmentosa. SKP, in contrary to widely used manual perimeter, gives a possibility of quantification of the visual field area. Future studies may be able to monitor the progression of the visual field loss caused by retinitis pigmentosa.