Abstract
Purpose: :
The EyeMapper is an instrument designed to perform fast, global aberrometry. This study compares the central refraction measurements for distance and near obtained with the EyeMapper, a Shin-Nippon NVision K5001 autorefractor (SN, Japan) and a Complete Ophthalmic Analysis System (COAS-HD, Wavefront Sciences, USA) aberrometer with the dynamic stimulation aberrometry (DSA) device (Optana, Germany).
Methods: :
Twelve participants, aged 18 to 30 years, with spherical equivalent ranging from plano to -6.00D (mean -1.85D ± 2.29D) and astigmatism <1.00D were enrolled and ametropic eyes were corrected using 1-Day Acuvue Moist soft contact lenses (Johnson & Johnson, USA). Measurements for distance and accommodative demands of 3, 4 and 5D were performed (5 repeats) using the three instruments. Fixation targets were a high contrast back-illuminated modified (8 arms) Maltese Cross, 6/12 and 6/24 Snellen Letter E. While the internal EyeMapper targets were telecentric, target sizes for the SN and COAS were adjusted for their respective distances. The order of testing with the instruments and target presentation was randomized. Only the right eyes were measured with the left eyes occluded during the measurement.
Results: :
For distance, the EyeMapper results were significantly more negative (0.60D, p<0.01) compared to SN, but were not different to COAS (p>0.05). Mean refractions obtained with all instruments indicated a lag of accommodation at all near distances. When compared to the EyeMapper and the COAS, SN measurements were significantly more positive (p<0.05) for all near distances (0.58D on average). For distance and an accommodative demand of 3D the EyeMapper results were not significantly different (p>0.05) to those obtained with the COAS, but were more positive for accommodative demands of 4 and 5D (p<0.04). There were no significant differences between the target types for each of the 3 near distances (p>0.55) and this was not dependent on any specific instrument (p>0.46).
Conclusions: :
In general, the EyeMapper results were in better agreement to those obtained with the COAS rather than the SN. SN is an open-view autorefractor and this could possibly explain the ‘more positive’ results obtained with this instrument compared to the EyeMapper and the COAS.
Keywords: accommodation • refraction • refractive error development