Normal Isopter Position in the Peripheral Visual Field in Goldmann Kinetic Perimetry

Abstract

Purpose: Often in young patients the question arises if a disease state has contracted their peripheral boundary of the visual field. Since the ‘hill of vision’ is steeper in the periphery, kinetic perimetry is more sensitive in detecting peripheral visual field abnormalities than static perimetry. In order to be able with kinetic perimetry to detect mild peripheral visual field constrictions, we determined the normal position of 4 isopters in the peripheral visual field. Subjects and Methods: Intraindividual sensitivity variations of the isopters in the peripheral visual field were determined in 3 normal subjects by one perimetrist. Then, in 22 subjects (19–42 years old) the position of the isopters V4e, III4e, I4e and I3e has been determined by one perimetrist. Visual fields were registered using a Goldmann kinetic perimeter. Results: The intraindividual sensitivity variations (measured as 1 standard deviation) for the isopter V4e was 0.98° and for the isopter I4e 1.13°. To visualize the normal isopter positions in the peripheral visual field, the average positions ± 2 standard deviations were plotted for the isopters V4e, III4e, I4e and I3e. Conclusion: In this study, we determined the normal position of 4 isopters frequently used to plot the peripheral visual field. The plots have been printed in a scale of 1:4 in order to facilitate its use. Photocopying the figures on transparencies by scaling them with a factor 4 will allow to superpose the transparencies on individual Goldmann kinetic visual fields in order to easily determine whether the individual isopters are inside or outside the normal range.