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Protein Deposition and Clinical Symptoms in Daily Wear of Etafilcon Lenses

Subbaraman, Lakshman N.; Glasier, Mary-Ann; Varikooty, Jalaiah; Srinivasan, Sruthi; Jones, Lyndon

doi: 10.1097/OPX.0b013e318269e583
Original Articles

Purpose. To determine the relationship between clinical signs and symptoms and protein deposition over 8 h of wear of etafilcon A lenses in symptomatic and asymptomatic contact lens wearers.

Methods. Thirty adapted soft contact lens wearers (16 symptomatic and 14 asymptomatic) were fitted with etafilcon A lenses. In vivo wettability, non-invasive tear break-up time, and subjective symptoms (vision, comfort, and dryness) were assessed at baseline and after 2, 4, 6, and 8 h. After 2, 4, 6, and 8 h time points, lenses were collected, and total protein, total lysozyme, and active lysozyme deposition were assessed.

Results. There was a significant reduction (p = 0.032) in the non-invasive tear break-up time at 8 h in both groups. In the symptomatic group, there was a significant reduction in subjective comfort and dryness ratings at 6 and 8 h measurement with respect to baseline (p < 0.05). There was a significant increase in total lysozyme and total protein deposition (p = 0.027) across all time points in both groups; most of the lysozyme remained active (>94% at 8 h). Pearson's correlations between subjective symptoms and protein deposition showed poor correlations for total protein/lysozyme and any subjective factor (r < 0.3; p > 0.05), and only weak correlations between dryness and % active lysozyme (r = 0.3 to 0.5 for all time points). However, stronger correlations were found between active lysozyme and subjective comfort (r = 0.6 to 0.7; p < 0.001).

Conclusions. In addition to investigating total protein deposited on contact lenses, it is of significant clinical relevance to determine the conformational state of the deposited protein.

*PhD, BSOptom, FAAO

MSc

MBBS, MSc

§PhD, BSOptom, FAAO

PhD, FCOptom, FAAO

Centre for Contact Lens Research, School of Optometry, University of Waterloo, Waterloo, Ontario, Canada.

Received January 3, 2012; accepted June 18, 2012.

Lakshman N. Subbaraman Centre for Contact Lens Research, School of Optometry University of Waterloo 200 University Avenue West Waterloo, Ontario Canada e-mail: lnagapat@uwaterloo.ca

© 2012 American Academy of Optometry