Performance of iPad-based threshold perimetry in glaucoma and controls.

IMPORTANCE

Independent validation of iPad visual field testing software Melbourne Rapid Fields (MRF).

BACKGROUND

To examine the functionality of MRF and compare its performance with Humphrey SITA 24-2 (HVF).

DESIGN

Prospective, cross-sectional validation study.

PARICIPANTS

Sixty glaucomas mean deviation (MD:-5.08±5.22); 17 pre-perimetric, 43 HVF field defects and 25 controls.

METHODS

The MRF was compared with HVF for scotoma detection, global indices, regional mean threshold values and sensitivity/specificity. Long-term test-retest variability was assessed after 6 months.

MAIN OUTCOME MEASURES

Linear regression and Bland Altman analyses of global indices sensitivity/specificity using (ROC) curves, intraclass correlations.

RESULTS

Using a cluster definition of three points at <1% or two at 0.5% to define a scotoma on HVF, MRF detected 39/54 abnormal hemifields with a similar threshold-based criteria. Global indices were highly correlated between MRF and HVF: MD r = 0.80, PSD r = 0.77, VFI r = 0.85 (all P < 0.0001). For manifest glaucoma patients, correlations of regional mean thresholds ranged from r = 0.45-0.78, despite differing array of tested points between devices. ROC analysis of global indices showed reasonable sensitivity/specificity with (AUC) values of MD:0.89, (PSD:0.85) and (VFI:0.88). MRF retest variability was low with (ICC) values at 0.95 (MD and VFI), 0.94 (PSD). However, individual test point variability for mid-range thresholds was higher.

CONCLUSIONS AND RELEVANCE

MRF perimetry, despite using a completely different test paradigm, shows good performance characteristics compared to HVF for detection of defects, correlation of global indices and regional mean threshold values. Reproducibility for individual points may limit application for monitoring change over time, and fixation monitoring needs improvement.