Post-cycloplegia myopic shift in an older population

Purpose: To demonstrate that use of a mydriatic agent remains a significant confounder in autorefraction of the presbyopic population. Methods: The pre- and post-cycloplegic autorefraction results of 37 subjects over 50 years of age were measured using a Humphrey-598 autorefractor. The results of both eyes were included in a multivariate regression analysis. Results: The average age of the patient sample was 63.4 years. The mean spherical equivalent (SEQ) shifts for the hyperopic, myopic, pseudophakic, and emmetropic eyes were -0.53 D (95% Cl -0.77 D to -0.39 D; p < 0.001), -0.38 D (95%CI -0.81 D to +0.04 D; p = 0.077), -0.49 D (95% CI -0.78 D to -0.20 D; P = 0.001), and -0.35 D (95% CI -0.59 D to -0.11 D; p = 0.004), respectively. Conclusion: Cyclopleged autorefraction in the presbyopic population is associated with a myopic shift that can potentially lead to overestimation of myopic prevalence. This is an important factor in comparing population studies where cyclogleged autorefraction is used in contrast to non-cyclopleged autorefraction and subjective refraction.