Analysis of the effective methods in determining the cytotoxicity of circle contact lenses using neutral red test / Syahidatul Atiqah Muhamad Nizammuddin

Potentially hazardous substances can affect the physiological structure of ocular surface on a daily basis. Damages to cornea from different materials and chemical variability from irritation and inflammation can cause mild discomfort due to tissue damage resulting in blindness. Therefore, the ocular toxicity test is required to make sure that the products are safe for the consumer. The aim of this study was to systematically synthesize evidence from previous studies on the methods used in neutral red (NR) test in determining the cytotoxicity and also to analyze the effectiveness of NR test in determining the toxicity of the pigments on circle contact lenses in reducing the number of cases of ocular irritancy due to the use of circle contact lenses. Variety studies of randomized clinical control trials (RCTs) that uses NR test in determining the cytotoxicity was selected and systematically assessed. The information obtained from the RCTs include type of cell line used, duration of the cells exposed or incubated with the test material and the volume of neutral red used in the studies. From all the 19 studies that met all the inclusion criteria, 14 studies assessed the cytotoxicity potential using Wong-Kilbourne derivative (WKD) Chang conjunctival cell line. 15 minutes was the most frequent of duration of the cells exposed/incubated with the test material used in assessing the cytotoxicity while four studies stated that they used 10, 30 and 60 minutes of incubation duration with the test material. The majority used 200 μl of neutral red in the cytotoxicity test. Therefore, the effective method in determining the toxicity of the pigments on circle contact lenses using NR test is by using Wong Kilbourne derivative of Chang conjunctival cell line, 15 minutes of exposure time with the test material and 200 μl of NR solution in reducing the number of cases of ocular irritancy due to the use of circle contact lenses.