The present study investigates the effects of pharmacologic pupil dilatation on ocular, corneal and internal aberrations.

Sixty-two right eyes of 62 healthy participants were included in the present study. Ocular, corneal and internal aberrations were measured with a KR-1W wavefront aberrometer (Topcon Corp., Tokyo, Japan) before mydriasis in mesopic conditions. After pupil dilatation with a mydriatic drug (phenylephrine chloride 0.5% + tropicamide 0.5%) (Mydrin-P, Santen, Osaka, Japan), the measurements were repeated. The wavefront data of 4-mm and 6-mm diameter zones were analyzed. The changes of aberrations before and after mydriasis were evaluated by paired t -test.

The values of ocular, corneal and internal spherical aberrations before and after mydriasis on the 4-mm diameter pupil zone were not statistically significantly different. On the 6-mm diameter zone, the ocular and internal spherical aberrations were statistically significantly different ( p = 0.025, p = 0.002, respectively, paired t -test). However, the corneal aberrations did not show significant changes. The internal aberrations average before mydriasis was -0.043 (±0.21) µm and was shifted in a negative direction to -0.093 (±0.17) µm after mydriasis. The ocular aberrations average also changed toward negative after mydriasis. The high-order aberrations and astigmatism did not change significantly.

The ocular and internal spherical aberrations changed toward negative with mydriasis in the participants' eyes suggesting the change of the ocular spherical aberration to be attributed to internal changes.