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L.N. Subbaraman, L. Jones, S. Srinivasan, J. Varikooty, M. Glasier; Clinical Signs & Symptoms and Protein Deposition in One Day Wear of Etafilcon Lenses in Symptomatic and Asymptomatic Subjects . Invest. Ophthalmol. Vis. Sci. 2006;47(13):2400.
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To determine clinical signs & symptoms, percentage active lysozyme, total protein and total lysozyme deposition over the course of one day with etafilcon (Acuvue 2; AV) lenses in symptomatic and asymptomatic subjects.
20 subjects (8 symptomatic and 12 asymptomatic) were fitted with AV lenses pre–soaked for 24 h in OptiFree Express. Visual acuity, in vivo wettability (scale of 0–4), Non–Invasive Tear Break–up Time (NIBUT), subjective ratings of vision, comfort, dryness and stinging (scale of 0–100) were assessed at Baseline, 2, 4, 6 and 8 h. At the end of 2, 4, 6 and 8 h measurements, lenses were collected and analyzed for total lysozyme & total protein deposition and percentage active lysozyme.
There was no significant difference (NSD) between the two groups for in vivo wettability (p=0.18), subjective vision rating (p=0.38), lysozyme activity (p=0.37) and total lysozyme & total protein deposition (p=0.26) at any visit. There was a significant difference between the two groups for subjective rating of stinging (p=0.02) at all visits; comfort and dryness were rated significantly better (p<0.05) by the asymptomatic group at 6 and 8 h. In the symptomatic group, there was a significant decrease in NIBUT at 8h (p<0.05), subjective comfort and dryness at 6 and 8 h visits (p<0.05). Lysozyme deposited rapidly (120±21µg lysozyme/lens at 2h) and there was a significant increase in total lysozyme and total protein deposition (p<0.001) across all time points in both the groups. Most of the lysozyme remained active (99±1% at 2h to 93.2±11% at 8h) and there was NSD at any time point (p>0.05).
There was a poor correlation between clinical signs & symptoms and protein deposition over the course of a day in subjects using an etafilcon A material. The reduction in comfort across the course of the day is greater in subjects who are symptomatic of ocular dryness, but these symptoms are not due to differences in protein deposition or lysozyme activity. The symptoms are more likely related to subtle surface wetting changes or differences in tear film composition.
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