Comparison of white and blue light assessment of the upper and lower palpebral conjunctiva

To compare upper and lower eyelids in terms of palpebral redness, and roughness under two lighting conditions, and assess the extent of association between redness and roughness.

This was a cross-sectional study conducted at The Netherlands Contact Lens Congress (2016). The palpebral conjunctivae of the right, upper and lower eyelids of 250 subjects were assessed using a slit-lamp biomicroscope. White light was used to assess palpebral redness and roughness. Roughness was also assessed using cobalt blue light and fluorescein. A 5-point grading scale was used to grade the conditions. The average and maximum grades of 5 zones for the upper, and 3 zones for the lower eyelid were used in the non-parametric analysis.

A significantly higher grading in palpebral roughness was found using fluorescein with blue light, compared to using white light, for both upper and lower eyelids (p < 0.001). Upper eyelids appeared significantly rougher than lower eyelids with white and blue light (p < 0.001). Correlations between redness and roughness for upper and lower eyelids were low to moderate (p = <0.001).

Palpebral roughness was scored more highly with blue, than white light, therefore these methods should not be used interchangeably. Also, roughness was more apparent in the upper eyelid, therefore eyelids should be assessed separately. Palpebral redness and roughness should be considered independent variables due to the low to moderate correlation between them. It is therefore recommended to first assess both eyelids first for redness using white light, followed by examination with fluorescein and blue light to assess roughness.