Boes D A, Spaeth G L, Mills R P, Smith M, Nicholl J E, Clifton B C
Wills Eye Hospital, William and Anna Goldberg Glaucoma Service and Research Laboratories, Jefferson Medical College, Philadelphia, PA 19107, USA.
J Glaucoma. 1996 Feb;5(1):9-14.
A consistent stereoscopic (stereo) effect in disc photographs is important to be certain that apparent depth changes are real and are not the result of artifact caused by a variable stereo angle. The purpose of this study is to compare the accuracy of relative depth assessments using three different stereo photo viewing methods.
We evaluated the ability of 12 observers to arrange sets of simultaneous stereo photographs (Nidek 3-Dx split-frame slides, Lentec transparencies) and sequential stereo photographs (Zeiss full-frame slides) according to apparent cup depth. Observer arrangements of each set of 10 photographs were compared to a "reference standard" sequence determined from cup depth measurements made by the Imagenet optic nerve analyzer.
The median number of sequence errors (n = 6) made by all examiners in arranging the Nidek 3-Dx simultaneous stereo slides was significantly lower than the median number of errors (n = 12) with the Zeiss sequential stereo slides.
Simultaneous stereo slides provide significantly more interobserver consistency for judgements of cup depth than sequential stereo slides.
