Straylight measurements in contact lens wear

(1) To quantify the effect of contact lens wear on straylight in rigid and soft contact lens wearers and (2) to relate findings to morphological changes and subjective complaints.

Straylight was measured using the Oculus C-Quant during contact lens wear and after contact lens removal in 30 rigid contact lens wearers and 30 soft contact lens wearers. Semi-quantitative (0-4) slit-lamp grading of anterior segment changes using Efron grading scales and contact lens characteristics were performed. Subjects answered a straylight questionnaire.

Soft contact lens wearers had a mean straylight of logarithmic value of the straylight parameter [log(s)] = 0.934 during contact lens wear and after contact lens removal [comparable to log(s) = 0.938 of age-matched normal eyes]. Rigid contact lens wearers had a mean straylight during contact lens wear of log(s) = 1.167. After contact lens removal, log(s) significantly decreased to 0.997 (P < 0.01). Straylight values with rigid contact lenses were strongly increased (P < 0.001) compared with age-matched normal eyes; after contact lens removal, these values decreased but remained elevated. Straylight in rigid contact lens wearers correlated with the amount of deposits on the contact lens (P < 0.01) but not with other variables of the contact lens score. The questionnaire showed more straylight complaints in rigid contact lens wearers than in soft contact lens wearers (P < 0.01).

Rigid contact lens wear leads to increased straylight during contact lens wear and after contact lens removal. This may be because of subclinical effects of contact lens wear on the cornea and is not seen in soft contact lens wearers.