The screen area, Ad diffuses the energy E Ad over an angle y. 
We assume a uniform field in the plane of the cornea so that 
2 
E or = E,/LS tely/2)1 7 
; ; 2 
Dnl 
nly a fraction of E COP will pass the eye equal to TR /E ar" 
A small area Ad of the diffusor surface will be imaged onto 
the. retina in an area Ar, Ad/Ar - (S/fT)^. This is comparable 
to the concentration factor of the eye lens in the.casse.of 
normal incidence but here, phase relationship is distroyed 
by the diffusor. 
Hence, the total energy reaching the retina 
9 sin(a/2) p R° 
  
ret T [a.f. t2(0/2) bg 072317 
Inserting additional valugs p = 0,2 and y = 45°, we obtain a 
retinal energy of 5,8.10 Jcm^?, safely beneath the limit 
of 7.1072 Jem? 
Note that the scatter properties of the diffusor are rather 
low. Of more importance are the incident angle.o/2, the 
distance a and the eye pupil radius R. 
The latter can be reduced further by projecting a smali 
white light beam in the eyes. This eliminates aiso' the glazy 
look when taking holoportraits. Eyelids should be closed 
whenever possible. 
c. Allowable oblique incident angle. If we assume the maximal 
passive viewing angie 6 to be 160° (ref.18), the maximal 
allowable deviation towards the beam from oblique viewing 
may be written NS = 80° - S - 10° 
Again, it is a safe practice to fix the viewing direction by 
the white light spot shining into the eyes, meanwhile reducing 
the pupil. 
7) CONCLUSIONS. 
If safety precautions are taken, double pulsed holographic 
interferometry can easely be applied on human beings in vivo. 
The information collected allows easy derivation of qualitative 
displacement data and even quantitative values can be derived, 
be it with more sophisticated set-ups and data acquisition. 
Extensive use of the technique demand for multidisciplinary 
team work. 
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