Abstract
Purpose :
Visual field sensitivity is known to have test-retest variability (TRV). We reported that sensitivity and the edge of scotoma influence the TRV strongly. We infer the fixation is related to the edge of scotoma. We examined the difference of TRV between Octopus 900 and micro perimeter MP3 which can inhibit the fixation error using auto-tracking and auto-alignment system.
Methods :
Seven eyes of 7 patients (mean age: 66±2.9) with glaucoma were studied. Octopus 900 and MP3 were used with target size III and background luminance of 31.4 asb to measure the sensitivity on the upper temporal meridian of 45 degrees from the fixation point to the eccentricity of 18.5 degrees with the interval of 0.5 degrees. The maximum luminance of Octopus900 was 4000 asb, and that of MP3 was 10000 asb. The sensitivity was evaluated 3 times at each point. The mean sensitivity (MS) and standard deviation (SD) were calculated from the sensitivity values of the 3 repeats at each test point. The SD was defined as the TRV. We also calculated the Spatial-SD, which was defined as the SD of the MS of 5 consecutive test points. Spatial-SD was used to examine whether the TRV was affected by the variability of spatial sensitivity change along the meridian. We did a multivariate regression analysis to look for the independent factors that best determined the TRV in each of Octopus 900 and MP3. We also compared the TRV of Octopus 900 with that of MP3 in 2 groups: 1) the group with the MS less than 19 dB and 2) the group with the MS 19 dB or more
Results :
In the Octopus 900 and MP3, the TRV increased as the MS was decreased. However, where the MS became 0 dB, the TRV decreased. Multivariate regression analysis showed the TRV was strongly influenced by the Spatial-SD (Octopus 900 t-value: 18.8, MP3 t-value: 14.8). In the group with the MS 19 dB or more, the TRV of MP3 was smaller than that of Octopus 900 significantly (p=0.013). In the group with the MS less than 19 dB, TRV of MP3 did not have significant difference (p=0.425).
Conclusions :
In the high MS group (>19 dB), the TRV of the MP3 became smaller because MP3 inhibited the fixation error.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.