Investigative Ophthalmology and Visual Science (supp), vol 37, No. 3, p. 3300

Bước tới: chuyển hướng, tìm kiếm
 Tạp chí Investigative Ophthalmology and Visual Science 1996 ; 3 (37):3300
 Tác giả   J. Bottari, B. Laidlaw, K. Pandey and Vo Van Toi
 Nơi thực hiện   Department of Biomedical Engineering and Comp. Sci. Depart., Biomedical Eng, Bioengineering Center,Tufts University, 4 Colby Street, Medford, MA 02155
  DOI   URL  [ PDF]


Purpose. To determine if this psychophysical technique is reliable enough for clinical studies.

Methods. The entoptoscope, equipped with a LCD Spatial Light Modulator, was used to stimulate the perception of leukocytes whose velocity and number were determined by three paradigms: Superimposing (Su), Alternating (Al) and Side-by-side (Si) (ref 1 and 2). The wavelength of the stimulated light was 430 nm, luminance 15 cd/m2 and field size 120. The measurements were triplicated, and the results were averaged and analyzed using standard statistical methods. All observers were healthy with normal vision. The diurnal fluctuation study was performed with three experienced male subjects; the measurement was established every two hours for 8 hours a day. The long term fluctuation study was performed with 10 naive subjects (6 males, 4 females, age: 20-50); each subject attended 10 measurement sessions for 6 consecutive weeks, the subjects were instructed not to change their living habits.

Results. Overall, neither the difference between subjects nor the variation of velocity were statistically significant. The coefficients of variance (CV) obtained with the Si paradigm were higher than those obtained with the other two paradigms and close to those obtained by Yap et al. (ref 3). Further, in the diurnal fluctuation study, the three paradigms yielded: (a) similar average velocity with different CV (Su=0.77mm/s± 10%, Al=0.77± 12%, Si=0.73± 22%) and (b) different average number with different CV (Su=80± 19%, Al=63± 22% and Si=72± 29%). In the long term fluctuation study, we found that: (a) the average values and the CV were compatible with those obtained in the diurnal fluctuation study, (b) the learning curve showed a strong effect in most subjects, (c) some subject performed be tter with one paradigm than another, however no single paradigm consistently yielded better results in all subjects and the preferable paradigm to the subject might not yield the lowest CV, (d) the average velocity did not change for the whole testing per iod while the average number of leukocytes tended to increase, (e) the testing time was shortest with the Su paradigm and longest with the Al.

Conclusions. (a) the velocity is a reliable parameter for clinical studies, (b) having experience is necessary to obtain repeatable results, (c) although the Si paradigm yielded larger average CV, some subjects performed b etter with it, therefore all three paradigms should be used.

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