Abstract
Purpose: :
Discomfort, dryness, redness, poor vision and shorter wear time are associated with drop out from low Dk soft lens daily wear (Pritchard et al 1999, Young et al 2002) but refitting with silicone hydrogel lens may alleviate these problems (Riley et al 2006, Dumbleton et al 2006). We examined factors related to discontinuation in silicone hydrogel daily wear (SiHy DW) to see if they differed from those reported in the literature for low Dk lenses.
Methods: :
This was a retrospective, case-control analysis of 5 SiHy lenses (lotrafilcon A, lotrafilcon B, galyfilcon A, senofilcon A, balaficon A) and 4 lens care solutions (ClearCare, AQuify MPS, Opti-Free Express, Opti-Free Replenish) worn in 20 combinations for 3 months by approximately 40 participants per combination. Discontinued participants (DC) were compared to those who completed each trial. Of the DC participants, data from those with adverse response at any point were excluded. Data from 2 week, 1 month, and 3 month visits and a 2 month questionnaire were analysed using chi-square tests and linear mixed model analyses.
Results: :
The non-adverse event related discontinuation rate was 10.7% in the first three months. An additional 4.5% of participants who discontinued after an adverse event were excluded from the analysis. Compared to those completing each trial, a greater proportion of DC participants were less than 20 years old (p=0.027), and were new to lens wear or SiHy lenses (p=0.001). There was no difference in gender, ethnicity, lubricating drop usage, no clinical difference in over-refraction sphere, uncorrected cylinder, visual acuity or slit lamp ocular physiology between the groups. The DC participants reported shorter hours of wear (p=0.001) and shorter hours of comfortable wear (p=0.000). The DC subjects reported higher frequency of moderate to severe blurred vision, discomfort, lens awareness, burning & stinging, dryness and redness (p<0.03). They rated their lenses lower for overall comfort, comfort on insertion, comfort during the day, comfort at the end of the day, ease of lens handling, overall vision, overall dryness, end of day dryness (p<0.01). They rated worse for burning & stinging, self reported redness, itching and overall awareness (p<0.01) compared to participants who did not discontinue.
Conclusions: :
The rate of subjective comfort related discontinuations was greater than those due to adverse events. Poor comfort, dryness, self reported redness, self reported poor vision and reduced wear time remained indicators for drop out from lens wear.
Keywords: contact lens • cornea: clinical science • clinical (human) or epidemiologic studies: risk factor assessment