Comparative analysis of pupillometry in two scheimpflug-based measurement systems

The primary aim of this study was to compare pupillometry measurements obtained from the Sirius™ and AL-Scan™ devices under different lighting conditions. Additionally, the secondary aim was to assess and compare the topographic (keratometric) measurements provided by these systems.

A non-interventional and prospective study was conducted on normal patients aged 18-45 years. Patients who did not smoke and had a spherical equivalent ranging from + 3.00 D to - 5.0 were included. Pupillometry measurements were taken after 1 minute of dark adaptation. Only the right eyes were compared for keratometry. All eyes were compared for pupillometry. We compared the K1 (D), K2 (D), KAvg (D), photopic pupillometry (PP), and mesopic pupillometry (MP) values.

We examined a total of 30 women (66.7%) and 15 men (33.3%). AL Scan showed an average K1 of 42.99 ± 1.50 D, an average K2 of 44.04 ± 1.74, and an average Kavg of 43.58 ± 1.62. Sirius topography yielded the following averages: 42.94 ± 1.51 for K1, 43.90 ± 1.75 for K2, and 43.41 ± 1.61 for Kavg. The average PP and MP measures obtained with the Nidek Al-Scan instrument were 3.97 ± 1.08 mm and 6.04 ± 1.08 mm, respectively. The Sirus device yielded average PP and MP values of 5.05 ± 1.04 mm and 6.01 ± 1.08 mm, respectively. Bland-Altman statistics showed a good degree of correlation between the MP measurements of both devices (p = 0.65). However, K1, K2, KAvg, and PP data showed no significant agreement between both devices (p < 0.05).

In our research, Sirius and Nidek Al-Scan equipment yield comparable MP data; however, PP is inconsistent. Device selection with repeated pupillometry data requires more investigation.