MAY 01, 2009
Because night driving difficulty is a common complaint in LASIK patients who also have night vision symptoms such as glare and halo, the authors chose to prospectively assess night driving performance before and after a refractive surgery procedure.
Records were reviewed from two LASIK clinical trials that had similar enrollment criteria. One trial treated patients with conventional LASIK using a bladed microkeratome (cLASIK); the other, with a wavefront-guided profile using a femtosecond laser (wLASIK).
Simulated night driving performance was assessed both before and six months surgery. In every category, there was a mean reduction in night driving performance after cLASIK, while the wLASIK group experienced a mean improvement in every category.
A clinical relevant loss of night driving performance (>0.5 seconds) was observed in 32 to 38 percent in the cLASIK group for all tasks assessed, compared to a 0 to 3 percent reduction with wLASIK. Performance improved significantly in 11 to 31 percent of the wLASIK group in every task, compared to 2 to 7 percent increase in the cLASIK group. The researchers note that wLASIK also improved mean visual performance compared with spectacles.
The authors draw three conclusions from their study:
- The added expense of wLASIK to correct myopia and myopia with astigmatism is clearly offset by a significant improvement in night driving performance over a conventional procedure in ideal LASIK candidates.
- The advantage of wLASIK in night visual performance will likely reduce the number of patients who have postoperative difficulty driving at night compared with cLASIK. This is significant because these patients may require much more clinical attention, expensive diagnostic workups, and can be difficult to treat.
- wLASIK improved mean visual performance compared with spectacles. The impact of providing a procedure that improves night visual performance over spectacles is unknown, but may herald a new appreciation and direction for refractive surgery.