Abstract
Purpose: :
To evaluate differences in wavefront refraction (WFR) and higher order aberration (HOA) measurements between three aberrometers in young and presbyopic patients under cycloplegia.
Methods: :
10 right eyes of 10 healthy volunteers were divided into two groups (n=5). Group 1: presbyopes (age 40 to 55), mean cycloplegic spherical equivalent (CSE) -1.25D and Group 2: young patients (age 20 to 35), mean CSE -1.68D. Three different aberrometer systems, LADARWave (ALCON), WaveScan (VISX/AMO) and Maxwell (Ziemer), were used to acquire WFR and HOA measurements after cycloplegia with tropicamide 1%. Zernicke terms were rescaled according to pre-selected pupil diameters (PD) of 5 and 6.5 mm for LADAR, Maxwell and WaveScan data. Differences in WFR and HOA measurements between paired aberrometers were assessed using T-test.
Results: :
Mean patient age for group 1 was 45.6 years (SD 5.1) and 26.4 years (SD 5.3) for group 2. In group 1, under PD of 5 mm, mean CSE (-1.25D) was -0.25 D lower than WaveScan SE (-1.00D) p=0.03. In group 2, under PD of 5 mm, mean Maxwell SE (-1.54D) was significantly lower than LADAR SE (-1.46D) p=.004; and mean LADAR SE (-1.46D) was also significantly lower than WaveScan SE (-1.00D) p=0.021. There were no statistically significant differences in WFR between the groups at PD of 6.5 mm. In group 1, under PD of 5 mm mean total LADAR RMS (2.78 µm) was statistically higher compared to WaveScan (2.33 µm) p=0.014; and defocus was statistically higher with LADAR (1.39 µm) compared to WaveScan (0.82 µm) p=.019. In group 2, under PD of 5 mm mean total Maxwell HOA (0.28 µm) was higher than LADAR total HOA (0.18 µm), p.003; in contrast total LADAR HOA (0.18 µm) was significantly lower than total WaveScan HOA (0.30 µm), p=.045. In group 2, under PD of 5 mm mean LADAR defocus (1.80 µm) was higher than Maxwell defocus (1.14 µm), p=0003 and Wavescan defocus (1.32D), p=.025. In group 1, under PD 6.5 mm LADAR defocus (2.70 µm) was higher than WaveScan defocus (1.59 µm), p.008; in terms of spherical aberration LADAR (0.20 µm) was higher than Maxwell (0.14 µm), p=0.012. In group 2, under PD of 6.5 mm in LADAR defocus (3.17 µm) was higher than Maxwell defocus (2.21 µm), p=0.002 and higher than VISX defocus (2.41 µm), p=.003.
Conclusions: :
Significant differences in HOA and WFR measurements were noted when comparing paired aberrometers under fixed pupil diameters and cycloplegic conditions. Diagnostic and therapeutic measurements should be performed using paired aberrometers and treatments should be laser platform specific.
Keywords: refractive surgery • refractive surgery: other technologies • refractive surgery: comparative studies