Dear Hoover,
Would you post it on cvnet? Thanks.
Dear group,
I had a 10 yo boy patient with congenital nystagmus. BCVA is 0.8 ou with
random-dot stereopsis at least 300 sec-arc.
I tested his binocular depth-from-motion with random-dot
kinematogram/stereogram (RDK/RDS) to notice that he could not recognize
the moving square within the kinematogram and the random-dot pattern
seemed stand still to him.
The pixel size is 5 min-arc and the square size is 5x5 degree. The
motion range is 5 min-arc and 3.5 Hz.
When showing two kinematograms with anaglyph, if squares to two eyes
oscillated at the same direction (ie. no depth cue) he could see a
square oscillated; if squares to two eyes oscillated at opposite
directions (for normal subjects the square looked jumping forward and
backward) he could see a square standing still withour depth motion.
What's the mechanism?
Did this frequency (3.5Hz) just meet his nystagmus frequency -- then the
square fixed on his retina, but the background should oscillate, why
couldn't he delineate the border of RDK?
Did vision of congenital nystagmus have lower sampling rate, lower than
7 samples/sec that he could not pick up two positions of the oscillating
square?
Why binocular viewing could get the oscillating square while monocular
viewing couldn't?
Why couldn't he get depth-from-motion when two squares (to two eyes)
oscillated at opposite directions? Remember that he has good static
stereopsis (better than 300 sec-arc).
Any reference for this phenomena in congenital nystagmus? What more
studies can I do on him to reveal vision mysteries of congenital
nystagmus?
Ai-Hou
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/* | Ai-Hou Wang, MD. PhD. Phone: 886-2-23970800 x 5187
/ ; Dept of Ophthalmology FAX: 886-2-23412875
| tw ; Natl Taiwan Univ Hospital
\ ; 7, Chung-shan S. Rd
`w Taipei, TAIWAN 100 ahwang@ha.mc.ntu.edu.tw
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