Comparison of two pupillometers in determining pupil size for refractive surgery.

Objective: To compare a handheld and a digital pupillometer in determining pupil size in a population of refractive surgery candidates (group 1) and after implantation of an Artisan phakic intraocular lens (PIOL) for correction of myopia (group 2).

Methods: Pupil size was measured with the Colvard and Procyon pupillometers in 121 eyes in group 1 and 83 eyes in group 2. Pupil sizes measured with the Colvard device were compared with the scotopic, mesopic-low and mesopic-high measurements taken with the Procyon pupillometer in both groups. Analysis of comparison between pupil measurements was performed according to methods described by Bland and Altman.

Results: The mean Colvard scotopic pupil diameter, scotopic, mesopic-low and mesopic-high Procyon pupil diameters were 5.86 +/- 0.81 mm, 6.42 +/- 0.88 mm, 5.55 +/- 0.95 mm and 4.21 +/- 0.73 mm in group 1 and 5.32 +/- 0.67 mm, 6.14 +/- 0.81 mm, 5.33 +/- 0.78 mm and 4.02 +/- 0.55 mm in group 2, respectively. The Colvard diameter compared most favourably with the Procyon mesopic-low diameter (group 2; p = 0.78).

Conclusions: Measurements of pupil diameter with the Colvard pupillometer correlated best with measurements taken by the Procyon pupillometer under standardized mesopic-low light conditions. We believe that digital binocular infrared pupillometry is advantageous for obtaining standardized measurements of pupil size.