PURPOSE: The introduction of silicone hydrogel lenses has created renewed patient and practitioner interest in thirty day continuous contact lens wear. Among the safety issues the practitioner is confronted with is the effect the lens has on the ocular surface. The present study examines this by use of impression cytology samples taken over a 90 day period to assess ocular surface health based on conjunctival goblet cell density.

METHODS: Twenty subjects, 13 females and 7 males with an average age of 31.17 years had baseline impression cytology performed prior to wearing Ciba Focus Night & Day (lotrafilcon A) lenses on a 30 day continuous wear schedule. The lenses were replaced every 30 days and impression cytology was performed at each replacement to assess goblet cell density.

RESULTS: Mean baseline goblet cell density was 4.26 %. After one month a small decrease was observed (3.875%). A further decline was observed in the second month to 2.4% and finally stabilization in month three at 2.57%. The standard deviation on the samples was 2.5%. The decrease we observed was not statistically or clinically significant.

CONCLUSIONS: This study suggests that there is no significant disruption of the ocular surface after three months of 30 day continuous wear of Ciba Focus Night & Day lenses.

ADDITIONAL COMMENTS: This study was supported by a grant from CibaVision.