Table 1.

Descriptive statistics for 95% distribution ellipsoids (see figure 2) for repeated NETRA samples for 279 right eyes.

Samples (n=279)	Clinical means* (Fs Fc A)	Means† ${\displaystyle {\left(\begin{array}{ccc}{F}_{\mathrm{I}}& F_{\mathrm{J}}& F_{\mathrm{K}}\end{array}\right)}^{\mathrm{T}}}$ ${\displaystyle ={\left(\begin{array}{ccc}M& J_0& J_{45}\end{array}\right)}^{\mathrm{T}}}$	Variances and covariances‡ ${\displaystyle {\left(\begin{array}{ccc}{S}_{\mathrm{I}\mathrm{I}}& S_{\mathrm{J}\mathrm{J}}& S_{\mathrm{K}\mathrm{K}}\end{array}\right)}^{\mathrm{T}}}$ ${\displaystyle {\left(\begin{array}{ccc}{S}_{\mathrm{J}\mathrm{I}}& S_{\mathrm{K}\mathrm{I}}& S_{\mathrm{K}\mathrm{J}}\end{array}\right)}^{\mathrm{T}}}$	Volumes§
NETRA test OD	$-$–1.87 –$-$0.09 × 167	${\displaystyle {\left(\begin{array}{ccc}-1.91& 0.04& -0.02\end{array}\right)}^{\mathrm{T}}}$	${\displaystyle {\left(\begin{array}{ccc}4.36& 0.17& 0.09\end{array}\right)}^T}$ ${\displaystyle {\left(\begin{array}{ccc}-0.10& -0.09& 0.02\end{array}\right)}^{\mathrm{T}}}$	63.26
NETRA retest OD	–1.90 –0.13 × 178	${\displaystyle {\left(\begin{array}{ccc}-1.97& 0.06& -0.01\end{array}\right)}^{\mathrm{T}}}$	${\displaystyle {\left(\begin{array}{ccc}4.27& 0.14& 0.07\end{array}\right)}^{\mathrm{T}}}$ ${\displaystyle {\left(\begin{array}{ccc}-0.09& -0.02& 0.01\end{array}\right)}^{\mathrm{T}}}$	51.43

*Units for clinical means are in dioptres and degrees (D, °)

†Units for vector (f) notation means are in dioptres (D)

‡Units for vector notation variances and covariances are in squared dioptres (D²)

§Units for volumes of 95% distribution ellipsoids are in cubic dioptres (D³)

NETRA, Near Eye Tool for Refractive Assessment.