An implantable phakic IOL designed to correct both myopia and astigmatism improves simulated night driving vision more than PRK, according to a new study.
Researchers in San Diego compared changes in simulated night driving performance among patients moderate to high myopia and astigmatism after treatment with either surgical implantation of a toric Visian Implantable Collamer Lens (STAAR Surgical; Monrovia, Calif.) or conventional PRK surgery.
A total of 43 eyes (20 bilateral cases) were treated with the Visian Toric Implantable Collamer Lens (TICL), and 45 eyes were treated with PRK surgery.
Prior to surgery, subjects participating in the study had -6.00 to -20.00 diopters (D) of myopia and 1.00 to 4.00 D of astigmatism.
Before and 6 months following treatment, 27 eyes of 14 TICL patients and 41 eyes of 21 PRK patients underwent a simulated night driving test. The test required the subjects to detect and identify common road signs and hazards with and without the presence of a glare source.
Examples of a glare source during real-world night driving are the headlights of approaching vehicles.
The results of the night driving simulator testing revealed:
- Without the introduction of a glare source, patients in the TICL group could identify road signs and pedestrian hazards significantly faster than patients in the PRK group.
- With introduction of a glare source, patients in the TICL group could identify pedestrian hazards (but not road signs) significantly faster than patients in the PRK group.
- There was no significant difference in how quickly subjects in the two treatment groups could detect (but not identify) road signs and pedestrian hazards, with and without a glare source.
The researchers concluded that the Visian Toric Implantable Collamer Lens performed better than conventional PRK surgery in the pre- to post-surgical simulated night driving visual performance testing, with and without a glare source present.
A full report of the study appears in the May 2010 issue of Journal of Refractive Surgery.
Tags: astigmatism, driving, night vision