Abstract
Purpose :
To consider whether an iPad perimetry application (MRF-glaucoma) can be used to measure the visual field of children with glaucoma.
Methods :
A total 26 children, 8-18 years old, with paediatric glaucoma (n=43 eyes) were recruited. All gave informed consent to participate and none had performed perimetry in the past. Children were tested with the MRF-glaucoma application (n=43) and with HFA 24-2 Sita-Standard (n=29). When Sita-Standard could not be completed, Sita-Fast was used (n=14). An attempt was made to balance order of presentation (60% MRF-HFA) across tests. Twenty-three children were retested with MRF at their next clinical visit (ave 6.9 ±5.5 months) giving 39 data sets to establish retest reliability by Bland-Altman methods. The thresholds and variability of children were compared to 20 young adults (students, average age 23 yrs) tested twice on the MRF.
Results :
Children had a mean age of 11±2.6 yrs (range 8 to 18 yrs ) with 16 eyes having mild defects (HFA MD<-6 dB), 14 moderate defects (-12<HFA MD<-6 dB) and 13 severe defects (HFA MD<-12 dB). Average test times for MRF (5.7±1.4 mins] and SITA-Fast (5.5±2 mins) were similar with both being significantly faster than SITA-Standard (8.2 ±1.3 mins, P<0.001). MRF MD correlated strongly with the HFA MD (ICC r=0.85) and Bland-Altman analysis found a 2.0 dB bias in MD with HFA<MRF. In 10 children who returned normal MD (>-0.5 dB), MRF thresholds were constant with eccentricity (~30 dB) and similar to adult values. Children show greater variability (x2) than adults with a Coefficient of Repeatability of 8.0 dB. Children return a high proportion of “unreliable” tests (MRF 65% v HFA 23%) with many having high false positive rates (FPR>15%: MRF 24% v HFA 12%) or unsteady fixation (fixation loss >25%: MRF 47% v HFA 35%). This was most pronounced in those <12 yrs of age. We found that averaging MRF outcomes across 2 tests improved outcomes: HFA MD (ICC r=0.92; p<0.05), reduced variability (70%) and improved the Coefficient of Repeatability (4.6 vs 8.0 dB; p<0.05).
Conclusions :
The MRF can be used to test the visual field of young children down to age 8. The reduced reliability in children is consistent with past reports. Our analysis shows that averaging two tests yields more repeatable outcomes.
This is a 2020 ARVO Annual Meeting abstract.