Fig. 8
From: New pediatric vision screener, part II: electronics, software, signal processing and validation
The two methods used to distinguish between central- and paracentral fixation. The circles are measurement with central fixation, whereas the crosses stand for paracentral fixation. a Simple threshold for (P 2.5 + P 6.5 )/P 4.5 (Method 1). b Three-way discriminant analysis (Method 2 for 3D case). Shown is the discriminant plane. a shows the threshold for (P 2.5 + P 6.5 )/P 4.5 , above which the eye is considered to fixate properly. b shows the discriminant plane according to Eqs. (4, 5 and 6) that best separates the same measurements in 3D parameter space