The phenol red thread tear test: a cross-cultural study.

PURPOSE: To examine the results of the phenol red thread tear test in a cross-cultural comparison. METHODS: Two groups of 500 controlled normal subjects who do not wear contact lenses from the United States and Japan were investigated. RESULTS: The mean wet length of the thread for the United States was 23.9 mm (SD 9.5 mm). The mean for Japan was 18.8 mm (SD 8.6 mm). There was a significant difference between the two countries (P < 0.05). Males subjects had significantly longer wet lengths than females for both countries (P < 0.05). There was a moderate correlation between right and left eye results for both countries. CONCLUSIONS: The phenol red thread tear test was found to be easy to administer. Results were in line with current knowledge and theories of the lacrimal system. Results also indicated that this test may disclose subtle differences not previously found with other tear tests.

Mascara pigmentation of the bulbar conjunctiva associated with rigid gas permeable lens wear.

We present three patients who were found to have unusual pigmentation of the bulbar conjunctiva. The areas, 1 to 2 mm in size, were translucent with dark black dust-like particles randomly placed within well defined borders. These specks were usually elevated, had a granular texture, and appeared to be overlying pingueculae. All three patients wore rigid gas permeable contact lenses, were found to have either a short tear break-up time or deficient tear aqueous layer, had associated 3:00 and 9:00 o'clock staining, and routinely used heavy mascara and/or eyeliner. In one patient, the areas resolved on discontinuing contact lens wear. The elevated areas may be associated with minor discomfort. We propose that a deficient tear layer and drying adjacent to the lens edge may compromise the conjunctival epithelium and prevent efficient washing of the pigment particles from the conjunctiva, allowing these granules to become embedded in the epithelium. Additional causes of conjunctival pigmentation are discussed.

An analysis of contact lens enzyme cleaners.

Currently, in the United States, the Food and Drug Administration has approved a number of enzyme cleaners for use with soft contact lenses. These cleaners contain three active enzymes--papain, pancreatin, and subtilisin. Although several studies have compared the cleaning efficacy of papain and pancreatin, little information exists concerning subtilisin. It was the aim of this investigation to compare the performances of four marketed enzyme cleaners, including Allergan Enzymatic (papain), Optizyme (pancreatin), ReNu Effervescent (subtilisin), and Ultrazyme (subtilisin A). Lenses were examined using the scanning electron microscope, and the amount of deposits on the lens surfaces quantified by digital analysis. All of the enzyme cleaners were effective in removing deposits from the contact lenses surfaces, but there was no significant difference in the cleaning efficacy of the four cleaners tested.