Pharmacologic dilation enables custom LASIK in eyes with small pupils

J Cataract Refract Surg. 2011;37(10):1847-1851

Custom LASIK yielded similar refractive outcomes in dilated and undilated eyes, a study found.

Investigators used the Visx S4 platform (Abbott Medical Optics), which requires a physiologic scotopic pupil of 5 mm to 6 mm to provide an accurate ablation zone, the study authors said.

"Patients whose pupils are smaller than 5 mm are excluded from wavefront-guided surgery with this platform," they said. "In addition, patients who are unable to relax accommodative tone are excluded from wavefront-guided ablation because they record an artificially more myopic (or less hyperopic) reading on the wavescan. If these scans are used for treatment, unwanted hyperopic outcomes can be expected. In these instances, obtaining wavescan aberrometry after pharmacologic dilation and cycloplegia would allow these patients to have custom LASIK."

The retrospective study included 52 eyes of 31 patients who underwent custom LASIK with dilated eyes. A control group included 104 undilated eyes of 55 patients.

Mean uncorrected distance visual acuity was 20/21 in the study group and 20/22 in the control group at 1 month postoperatively. At 3 months, uncorrected distance visual acuity was 20/22 in the control group and 20/20 in the comparator group.

Mean spherical equivalent was +0.07 D in the study group and +0.14 D in the control group at 1 month. Mean spherical equivalent was -0.01 D in the study group and +0.02 D in the control group at 3 months.

Both groups had statistically similar root mean square error, postoperative coma, trefoil and spherical aberration. The study group had a higher enhancement rate than controls but the difference was not statistically significant.

Future study with a larger patient sample is warranted, the authors said.