Contact lenses may reduce night vision

BRISBANE, Australia, Nov. 5 (UPI) -- An Australian researcher says drivers wearing multifocal contact lenses that correct an inability to focus on up close items may make driving at night harder.

Byoung Sun Chu, Ph.D -- formerly of the School of Optometry, Queensland University of Technology, Brisbane, Australia -- suggests those wearing multifocal contact lenses to correct presbyopia, an inability to focus on objects up close that increases with age, may have greater difficulty driving at night than those wearing glasses.

The study, published in Investigative Ophthalmology & Visual Science, found multifocal contact lens wearers had less ability to recognize road hazards and saw road signs at a much shorter distance than those wearing glasses at night.

"For those patients who drive long distances and hours at night, practitioners should carefully consider the best form of correction of presbyopia," Chu says in a statement.

Chu and colleagues measured the performance of 11 adults ages 45-64 who drove on a closed circuit driving track at night. Chu notes the relatively small sample size likely led to an underestimation of some of the differences and suggests conducting studies with a larger sample size to confirm the study findings.