The most common problem reported in contact lense wearers is dry eyes, which often leads to people being able to wear lenses for short periods only, or discontinuing lenses altogether.
When you wear contact lenses there is a physical affect on tears, causing them to evaporate more quickly, leading to drier eyes.
A small study (Cont Lens Anterior Eye, 2008) has shown a significant improvement in dryness, as well as an improvement in overall lense comfort after taking Evening Primrose Oil for 6 months.
The essential fatty acids in this supplement are often prescribed for conditions requiring additional lubrication - for instance arthritic joints. It may well be that the anti-inflammatory action of Evening Primrose Oil, as well as the additional lubrication provided by the oil to the eyeball have contributed to the reduction in symptoms.