The characteristics of corneal staining in successful daily and extended disposable contact lens wearers

Abstract

Purpose: The aim of this investigation was to measure levels of corneal staining in successful daily and extended wearers of disposable hydrogel contact lenses.

Methods: Twenty‐four subjects on a daily wear (DW) schedule and 20 subjects on an extended wear (EW) schedule were examined at six‐monthly intervals over a two‐year period. Subjects wore two types of disposable hydrogel lenses. Measurements were taken from the eye wearing an etafilcon A contact lens only. The cornea was divided into five equally sized zones and the extent and depth of corneal staining were assessed on a zero to four scale.

Results: The overall levels of corneal staining were low with median values below or equal to grade 0.5 in all groups. There was no difference in the extent, depth or geographical distribution of corneal staining between the DW and EW groups. Staining was more frequently recorded in the superior and inferior areas of the cornea than in the central, nasal or temporal regions (Pearson's Chi‐Square, p < 0.10).

Conclusions: The mode of wear with disposable contact lenses is not a contributing factor to the amount of corneal staining seen in successful wearers. Low levels of corneal staining should be expected in successful DW and EW wearers.

Key words:

• corneal epithelium
• corneal staining
• daily wear
• extended wear
• sodium fluorescein