Abstract
Abstract: :
Purpose: To assess normative values for local kinetic thresholds depending on age and various stimulus conditions (luminance, size, angular velocity), also considering individual reaction time (RT). Methods:We enrolled 84 eyes of 84 normal subjects (12 per decade) from 10 to 79 years of age. RE/LE was chosen at random; results of LE were mirrored. SKP was carried out with the OCTOPUS_101 perimeter (INTERZEAG, Schlieren, CH). Background luminance was kept constant at 10 cd/m2. According to the Goldmann classification, we used the following combinations of stimulus size, luminance and angular velocity: III4e with 5°/s, III4e with 25°/s, I3e with 5°/s, and I2e with 2°/s, respectively. For each stimulus condition, four centripetal stimuli were presented along the eight cardinal (two horizontal, two vertical, four oblique) meridians in random order. Individual RT was assessed by placing (at least two) centripetal vectors within the central visual field region, i.e. within the isopter of the related stimulus characteristics. Local kinetic thresholds (i.e. related eccentricity values) were corrected for the distance covered in individual geometric mean RT. Mean local kinetic thresholds were explained by the factors stimulus condition and meridian and covariable age, together with their two-way interactions in an ANCOVA with logarithm of variance depending on meridian. Results: Model fit was good (R²=0.85). Kinetic thresholds for the III4e stimulus were not influenced by target velocity and turned out to be almost independent of age, too. In contrast, thresholds for dim and small stimuli exhibited a clear age dependence with an approximate 1° decline per decade. Dispersion (standard deviation = SD) of kinetic thresholds generally tended to increase with eccentricity, target luminance, size or angular velocity. SD also varied markedly along each isopter with maxima of 9° in the oblique lower nasal, and oblique upper temporal meridians, and a minimum of 6° in the horizontal temporal meridian. Conclusions: This is the first study of age-related normative values in semi-automated kinetic perimetry, which are corrected for individual reaction time while assessing local kinetic threshold. Isopters of large and intense stimuli are mainly influenced by cupola and anatomy related characteristics, whereas kinetic thresholds of dim and small stimuli exhibit a clear age dependence. Local dispersion varies markedly along an isopter.
Keywords: visual fields • perimetry • neuro-ophthalmology: diagnosis