Article
Comparison of infrared pupillometers and CCD-camera imaging from aberrometry and videokeratography for determining mesopic pupil size
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Authors
Published: | September 22, 2004 |
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Outline
Text
Objective
Measurement of mesopic pupil diameter is part of the preoperative evaluation of refractive patients, and it is taken into consideration, when a refractive procedure is planned. New aberrometry and topography devices provide pupil size measurements. In this study, such devices were compared to infrared pupillometers.
Methods
Pupil diameter was measured in 100 eyes of 51 patients after 2 minutes of dark adaptation using the following devices: Procyon (digital infrared pupillometer), Colvard (handheld infrared pupillometer), Zywave (fixating target switched off and on) and Wasca (aberrometer), and Orbscan II (corneal topographer). Measurements taken with the Procyon pupillometer were considered as reference values. Statistical evaluation was performed using the Bland-Altmann method for comparison of measurement techniques.
Results
Mean pupil size (mm) was 6.10 ± 0.86 with Procyon, 5.68 ± 1.07 with Colvard, 5.91 ± 1.01 with Zywave with the fixating target turned off, 5.09 ± 1.14 with Zywave with the fixating target turned on, 5.59 ± 0.99 with Wasca and 3.75 ± 0.67 with Orbscan. The limits of agreement were smallest for measurements between Procyon and Colvard, and largest for measurements between Procyon and Orbscan. The sign test revealed statistically significant differences for all devices in comparison to the Procyon pupillometer (in all cases P < 0.001), except for the Zywave aberrometer with the fixating target turned off (P = 0.13).
Conclusions
The Zywave wavefront sensor with the fixating target turned off provided measurements of scotopic pupil diameter that were closest to the reference values (Procyon). All other devices showed statistically significant differences.