Strong currency headwinds saw LED lighting producer ProPhotonix post a flat annual pre-tax loss.The London-listed group reported a loss for 2014 of $1.3m (£0.87m) compared with a $1.2m loss the year before, as a $1m loss in foreign currency exchange weighed on a 5.12% increase in revenue to $16.4m.Order bookings fell 9% in 2014 compared to 2013, the company said, adding its order backlog at the end of the year was down 20%, which it attributed to customers preferring to place smaller orders more often, rather than opting to place large orders all in once.The group added that some of its industrial customers had been affected weakness in their businesses and currency headwinds, which resulted in a number of large orders being delayed.ProPhotonix said it had begun 2015 in "a strong position", as many products it was developing in 2014 are now completed, but warned that the strengthening of the dollar could have a negative affect on its revenue growth in the current financial year.ProPhotonix shares were up 7.62% to 2.83p at 11:31 on Thursday.