Return to Presentations The precision of Wavefront Analysis Technology wavefront refraction compared to subjective and autorefraction Presented in Tampa Bay, Florida, December 2004, sponsored by AAO. Published in Optom Vis Sci Suppl 81:S157
Katrina E Parker, OD
Han Cheng, OD PhD
Konrad Pesudovs, BScOptom PhD PGDipAdvClinOptom MCOptom FAAO FVCO FCLSA
Raymond A Applegate, OD PhD FAAO
Abstract
Aim. To determine the precision of the Wavefront Analysis Technology (WAT) refraction (calculated using all information in the measured wavefront as opposed to a simple second order wavefront error analysis), and to compare this with lower order (LO) wavefront refraction, subjective refraction and autorefraction.
Methods. Four clinicians tested 16 normal subjects under cycloplegia by subjective refraction, autorefraction on two machines (Nidek AR-800, Topcon KR-8000) and wavefront sensing using the Wavefront Sciences Complete Ophthalmic Analysis System to calculate the WAT refraction. The lower order refraction also incorporated spherical aberration and secondary astigmatism terms from the 4th and 6th orders. All refraction data were converted to 3D dioptric space vectors (M, J0, J45) by vector analysis. Within and between observer agreement was determined using Bland-Altman limits of agreement (LOA).
Results. The subjects were aged 23.63±1.15 years, 68.8% female with an average refractive error of (M, J0, J45) -3.03±2.55, 0.05±0.39, 0.04±0.30. The test retest (within observer) repeatability (LOA for M, J0, J45) for individual measurements were: WAT refraction (±0.25, ±0.17, ±0.12), LO refraction (±0.32, ±0.16, ±0.16), Nidek (±0.16, ±0.08, ±0.06) and Topcon (±0.11, ±0.04, ±0.03). Interobserver LOA for individual measurements were: WAT refraction (±0.30, ±0.20, ±0.15), LO refraction (±0.39, ±0.8 ±0.42), Nidek (±0.30, ±0.17, ±0.10) and Topcon (±0.18, ±0.10, ±0.06). Averaging across 5 measures improved interobserver LOA: WAT refraction (±0.13, ±0.10, ±0.07), LO refraction (±0.19, ±0.09, ±0.20), Nidek (±0.26, ±0.13, ±0.08) and Topcon (±0.15, ±0.09, ±0.04). The interobserver precision of all 3 automated measures was superior to subjective refraction (±0.48, ±0.20, ±0.13).
Conclusions. In normal subjects, WAT refraction has comparable precision to lower order wavefront refraction, autorefraction and all are more repeatable across clinicians than subjective refraction. The precision of the WAT refraction can be improved by averaging over 5 measurements.