Methods: Six eyes of cataract patients who had previous myopic LASIK were implanted with LALs (Calhoun Vision, Pasadena, USA). Two weeks after surgery, we measured the refraction, SA, DOF and pupil diameter. Then, the LALs were irradiated with appropriate profiles to adjust the patients’ refraction and SA in order to optimize DOF and the quality of near vision. Through-focus visual acuity (VA) was measured using trial lenses and a DOF curve was fitted using a normalized 3-parameter Gaussian function. A DOF parameter was estimated as the dioptric power range providing decimal VA equal or better than 0.8.
Results: In eyes with high positive SA (over 0.30 microns for 4-mm pupil diameter) and small pupil diameter (3 mm), the pre-adjustment DOF was between 2.1 and 4.0 D (control group 1.9 D). In these cases, the final refraction was adjusted to fit the DOF to the optimal position. In the eyes with smaller SA values, DOF was lower. In these cases, the LALs were adjusted to induce negative values of SA increasing DOF up to values between 2.5 and 3.0 D. After proper customization, near VA (at 40 cm) was better than J2.
Conclusions: LALs implanted in post-LASIK patients allow customization of the range and power position of DOF by adjusting refraction and SA. This customized optimization procedure provides good near vision while maintaining high distance VA.