identified the leading primary obstetric causes of TPRL as being antepartum haemorrhage (APH), spontaneous PTL, unexplained IUD, infection and fetal abnormalities (Table VI).
The TPRL rate has decreased in TBH although the number of deliveries has increased.
Intra-uterine deaths, neonatal deaths, total perinatal related losses and perinatal mortality rates for 1986, 1993 and 2007 Rate/1 000 births 1986 1993 2007 Total number of singletons 7 923 8 616 10 396 IUD 27.4 26.5 20.0 NND 9.3 4.1 6.2 TPRL 36.7 30.5 26.2 PNM 33.9 29.2 25.3 Table VI.
Thus, realistic text maps cannot be produced if the tPRL (or fovea) moves randomly within a rectangular area.
Figure 18 shows a simulation of three tPRLs. The simulated subject scanned the text with a tPRL that was first to the left, then to the right, and finally, above the scotoma (the shaded area in center).
An important finding is that the PRL used for fixating (fPRL) was not necessarily used for scanning text (tPRL).
Similar text maps can be produced by simulations in which disorderly sequences of retinal shifts ("saccades") bring the fovea (or tPRL) to text characters.
Other subjects, however, scan text with the tPRL, a retinal area that is different from the fPRL.
Abbreviations: fPRL = fixation preferred retinal locus, fps = frames per second, PRL = preferred retinal locus, SD = standard deviation, SLO = scanning laser ophthalmoscope, tPRL = text-scanning PRL.