ASCRS, March 25-29, 2011, San Diego

1. Influence of Mydriatic Eye-drops on Wavefront-sensing and Automated Refraction Taneri S, Oehler S,MacRae S M, Yoon GTheauthorshave no financialinterest in thesubject matter of thisposter. ASCRS, March 25-29, 2011, San Diego

2. Background andPurpose • Wavefront-guided ablations are based on wavefront sensing: in a pupil dilated under mesopic conditions (in this poster entitled ‘miosis’) or after the application of mydriatic eye-drops (in this poster entitled ‘mydriasis’) • Question: Is there an influence of mydriatic eye-drops on wavefront-sensing in terms of the phoropter-predicted-refraction (PPR) of the Zywaveaberrometer or on automated refraction?

3. Methods • Prospective study of 200 myopic eyes, measured in dim light and pharmacologically induced mydriasis with an aberrometer (Zywave) and with automated refraction • Comparison of Predicted Phoropter Refraction (PPR) for a pupil diameter of 3.5 mm with and without pharmaceutical mydriasis, respectively • 100 eyes dilated with tropicamide 0.5% + phenylephrine 2.5% eye-drops, 100 eyes with tropicamide 0.5% alone

4. Methods RefractiveBaseline of the2 groupsbeforepharmaceuticalmydriasis

5. Results: Aberrometer • PPR values obtained in mydriasis were less myopic than in miosis Difference between dim light pupil dilation and pharmacologically induced mydriasis *: statistically significant

6. Results: Sphere & SphericalEquivalent • Aberrometer and autorefractor displayed a hyperopic shift of sphere and spherical equivalent in most eyes • Hyperopic shift of spherical equivalent with tropicamide and tropicamide combined with phenylephrine was significant with both devices (aberrometer and autorefractor) • No differencebetweenthetwomydriaticsolutionswerefound • Aberrometer was moreaffectedbymydriaticeyedropsthantheautorefractor • Age had no influence on theamount of thedifference

7. Results: HOA Change of HOA after pharmacologic pupil dilation Statistically significant Group I: mydriasis with tropicamide 0.5% + phenylephrine 2.5%, n = 100 Group II: mydriasis with tropicamide 0.5 %, n = 100 Applying tropicamide alone or combined with neosynephrine lead to significant inaccuracy in the determination of some HOA terms

8. Conclusion I Effect on lower order aberrations • There seems to be a cycloplegic effect from mydriatic eye-drops as both aberrometer and autorefractor displayed a significant hyperopic shift of sphere and spherical equivalent in most eyes. • The range of difference for the sphere component of the PPR was >1.5 D in both groups. • This is much higher than the accuracy of modern excimer lasers and may partially account for clinically significant over- or undercorrection of defocus in laser vision correction.

9. Conclusion II The hyperopic shift after pharmaceutic pupil dilation should be taken into account when interpreting aberration measurements and planning a wavefront-guided ablation. Consequently, it seems ideal to avoid the wide-spread use of mydriatics prior to wavefront sensing by mathematical expansion of data measured over a naturally dilated pupil.

10. Thankyou!