IPad-based noise-field perimeter can detect glaucomatous visual field loss

The visual field fast (VFF), a free iPad-based noise-field perimeter, can reliably and accurately detect glaucomatous scotomas, a recent study has found. Its performance for localizing and detecting such lesions, however, could still be improved further.

Researchers conducted a cross-sectional analysis of 66 eyes from 66 glaucoma patients. VFF was compared against the clinical-standard Humphrey visual field (HVF) test in terms of the following: correspondence in scotoma detection, agreement and correlation of scotoma size, test repeatability, and test duration, among other criteria. A parallel group of 30 eyes from 30 healthy controls was also included.

When using the HVF pattern deviation plot as a comparator, VFF was able to detect 52 of 57 glaucoma patients (91.2 percent); one control was falsely identified as positive. VFF was also able to localize 79.3 percent (146 of 184) of abnormal quadrants, while 14.6 percent (23 of 157) of healthy quadrants were falsely tagged as abnormal.

The VFF-estimated scotoma area correlated significantly and positively with HVF area (r, 0.268; p=0.044), though researchers noted a significant underestimation of scotoma area using the former vs latter method (21.0 percent vs 44.0 percent; p<0.01).

Using the HVF total deviation plot as a reference did not meaningfully alter the performance indicators of VFF, though its underestimation of scotoma area was amplified (21.0 percent vs 85.4 percent; p<0.001).

Of note, VFF showed high quantitative repeatability for whole-field and quadrant analyses, with intraclass correlation coefficients of 0.96 (p<0.0001) and 0.82–0.96 (p<0.001 for all), respectively.