Corneal staining and comfort observed with traditional and silicone hydrogel lenses and multipurpose solution combinations

BackgroundAssessment of ocular responses associated with lens and contact lens solution combinations was undertaken to address recent reports of toxicity caused by lens solutions resulting in high levels of corneal staining.MethodsDouble-masked, randomized, crossover, clinical studies were conducted at one research site. Before wear, new lenses were soaked at least 12 hours in marketed lens care solutions. Unisol 4® Preservative Free Saline (Alcon Labs, Fort Worth, Texas) was also assessed and served as a control. Corneal staining [severity (0-4) and area (0-100%)] and comfort were evaluated.ResultsThe majority of observed staining was micropunctate. PureVision lenses in combination with the biguanide-preserved solutions resulted in excessive staining area at 2 hours (ReNu MultiPlus, 73%; Complete MoisturePlus, 48%; AQuify, 21%). Staining tended to decrease throughout the wearing day, but several biguanide solution/lens combinations continued to exhibit excessive staining at 4 hours. Similar to saline, Opti-Free Express and RepleniSH as well as Clear Care exhibited minimal staining area, averaging 7% or less at 2 hours across all lens brands. Subjective comfort tended to decrease with higher levels of corneal staining area.ConclusionSome solution/lens combinations may cause excessive corneal staining 2 to 4 hours after lens insertion. Patients with high levels of corneal staining may experience decreased comfort.