Table 3.

Accuracy of PeekNV as a NVI Screening Test

Parameter	Point Estimate	Lower Bound 95% CI	Upper Bound 95% CI
Sensitivity	89.61%	85.19%	94.03%
Specificity	95.28%	92.21%	98.35%
Positive predictive value	93.24%	89.61%	96.88%
Negative predictive value	92.66%	88.88%	96.44%
Diagnostic accuracy	92.90%	88.23%	95.80%
Cohen's kappa (unweighted)	0.85	0.708	0.998

NVI defined as vision worse than N6 at 40 cm. The reference test was the conventional Tumbling “E” chart. These results are for the right-eye-first examination only, as when used in other contexts the test will usually only be used once, without practice effect.