[Influence of mydriatic eye drops on the aberrometer predicted phoropter refraction].

BACKGROUND AND PURPOSE

Wavefront-guided ablations are based on wavefront sensing in a pupil dilated under mesopic conditions, or in patients with insufficient natural pupil dilation, after the application of mydriatic eye drops. The aim of this study was to investigate a potential influence of mydriatic eye drops on wavefront-sensing in terms of the predicted phoropter refraction (PPR).

METHOD

In this prospective study 70 myopic eyes were measured in miosis and pharmacologically induced mydriasis with the Zywave aberrometer and automated refraction (Canon R-F10). 52 eyes were dilated with eye drops containing tropicamide 0.5 % and phenylephrine 2.5 %, in the remaining 18 eyes tropicamide 0.5 % was used. The PPR for a pupil diameter of 3.5 mm in miosis and in mydriasis, respectively, were compared and correlated to the corresponding values of the automated refraction.

RESULTS

PPR values obtained in mydriasis were less myopic than in miosis. The sphere of PPR differed by an average of + 0.19 +/- 0.3 diopters (range: -1.07 to + 0.37 diopters) when using tropicamide 0.5 % and phenylephrine 2.5 %. With tropicamide 0.5 % eye drops the difference was + 0.25 +/- 0.4 diopters (range: -1.12 diopters to + 0.27 diopters). Cylinder values were not affected. Automated refraction yielded a smaller difference of + 0.16 +/- 0.33 diopters (tropicamide 0.5 % and phenylephrine 2.5 %) and + 0.1 +/- 0.19 diopters (tropicamide 0.5 %). Cylinder values changed significantly.

CONCLUSION

The cycloplegic effect of mydriatic eye drops should be taken into account when interpreting aberration measurements and planning a wavefront-guided laser ablation.