Abstract
Purpose: :
A previous study has shown that the rate of microbial keratitis is comparable to the rate corneal erosions coupled with gram negative contamination of lenses. A retrospective analysis was conducted to determine if cleaning or replacing lenses in the morning or evening, during continuous wear, influenced the rate of corneal erosions.
Methods: :
Previously conducted continuous wear studies at the same site consisted of: morning lens replacement study (n=87) and evening lens replacement study (n=90) where subjects discarded worn lenses and replaced with a new lens each morning or night, respectively; morning lens cleaning study (n=100) where subjects removed and cleaned lenses with a commercial multipurpose solution (COMPLETE® Easy Rub™, Abbott Medical Optics, USA) and immediately reinserted the lenses. The historical control was monthly lens replacement (n = 95) where lenses were worn for one month and then discarded. All subjects were dispensed with silicone hydrogel lenses (lotrafilcon A, CIBA VISION, USA) on a 30-night overnight wear schedule. Clinic visits were conducted at 1 week, 1 month and 3 months.
Results: :
Logistic regression analysis showed a reduced risk of mechanical events (corneal erosion, superior epithelial arcuate lesion, contact lens papillary conjunctivitis) with morning lens replacement (0.8%, p = 0.013 [1 month]) and morning lens cleaning (1.0%, p = 0.031 [1 month] and p = 0.042 [3 months]) compared to nightly lens replacement (3.4%) and monthly lens replacement (5.2%). These mechanical events were driven primarily by corneal erosions, the incidence of which was 0.6% for morning lens replacement, 0.5% for morning lens cleaning, 3.4% for nightly lens replacement and 3.1% for monthly lens replacement.
Conclusions: :
Continuous contact lens wear related ocular mechanical adverse events can be reduced by changes in cleaning or replacement modality and such changes may be related to elimination of the overnight ‘debris accumulation’ with a morning replacement / cleaning modality.
Clinical Trial: :
http://www.anzctr.org.au ACTRN12610000336088
Keywords: contact lens • clinical (human) or epidemiologic studies: outcomes/complications