title: Seven-day extended wear and 30-day continuous wear of high oxygen transmissibility soft silicone hydrogel contact lenses: a randomized 1-year study of 504 patients.
abstract: OBJECTIVE
  To compare the performance and complication rates of PureVision (Bausch & Lomb, Inc.) high Dk/t silicone hydrogel lenses in 30-day continuous wear and 7-day extended wear.
  
  
  METHODS
  Five-hundred four (504) patients were randomized to 30-day continuous wear (353 patients) or to 7-day extended wear (151 patients) and followed for 12 months.
  
  
  RESULTS
  Eighty percent of patients did not report any symptoms/complaints at the follow-up exams. There were no cases of microbial keratitis. The annual incidence of the four most common clinically significant positive slit lamp findings related to lens wear for the 30-day and the 7-day groups, respectively, were as follows: corneal staining, 10.5% and 10.6%; corneal infiltrates, 4.6% and 2.3%; slight epithelial edema, 2.0% and 3.6%; and tarsal conjunctival abnormalities, 1.6% and 3.0%. There was no significant difference in complication rates between the groups. For reasons related to lens wear, 7.6% in the 30-day group and 13.2% in the 7-day group were dropped from the study. The patients' subjective judgment of comfort, visual quality, freedom from dryness, and lens handling varied from 89 to 95 on a scale of 0 to 100. The success rate was 82.9%, slightly better for the 30-day group (84.4%) than for the 7-day group (79.5%).
  
  
  CONCLUSIONS
  The complication rate was low. Sight-threatening events, such as bacterial keratitis did not occur. Inflammatory changes were seen, although at a low rate. Anterior segment changes related to hypoxia were minimal. Limbal and bulbar hyperemiadecreased significantly after switching patients to PureVision lenses. There was no significant difference in complication rates between the 30-day group and the 7-day group.
authors.affiliation: Department of Ophthalmology, Linköping University, Sweden.
authors.forename: S E
authors.initials: SE
authors.lastname: Nilsson
mesh_terms: D000293:Adolescent; D000328:Adult; D003262:Contact Lenses, Extended-Wear / Q000009:adverse effects / Q000706:statistics & numerical data; D003315:Cornea / Q000378:metabolism; D015818:Eye Infections, Bacterial / Q000209:etiology; D005260:Female; D006801:Humans; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D015994:Incidence; D007634:Keratitis / Q000209:etiology; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000378:metabolism*; D010539:Permeability; D011446:Prospective Studies; D012826:Silicone Elastomers; D013997:Time Factors
chemical_list: D012826:Silicone Elastomers; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D010100:Oxygen