The purpose of this study was to determine the corneal epithelial alterations induced by various types of contact lenses. By employing the specular microscope, the corneal epithelia of 60 patients who had worn contact lenses for more than 1 year were re-examined along with 15 myopic controls. The morphological changes in aphakic patients who changed from extended wear soft to extended wear rigi...

PURPOSE The purpose of this study was to measure upper and lower tear menisci on contact lenses using real time optical coherence tomography (OCT). METHODS Both eyes of 20 adapted contact lens wearers were imaged when they wore two types of silicone hydrogel lenses, balafilcon A on one eye and galyfilcon A on the other eye. The height, radius, and area of upper and lower tear menisci were obt...

More than 125 million people wear contact lenses worldwide, and contact lens use is the single greatest risk factor for developing microbial keratitis. We tested the antibacterial activity of multipurpose contact lens solutions and their individual component preservatives against the two most common pathogens causing bacterial keratitis, Pseudomonas aeruginosa and Staphylococcus aureus The in v...

RATIONALE Dry eye is the most prevalent condition seen by the ophthalmologist, in particular in elderly. The identification of new common risk factors (computer use and contact lens wear) extends the disease among the young people. The early diagnosis of dry eye is essential, but difficult, because the biochemical changes in tear film usually occur before any detectable signs. Due its advantage...

PURPOSE To determine the utility of a range of clinical and non-clinical indicators to aid the initial selection of the optimum presbyopic contact lens. In addition, to assess whether lens preference was influenced by the visual performance compared to the other designs trialled (intra-subject) or compared to participants who preferred other designs (inter-subject). METHODS A double-masked ra...

PURPOSE To examine the hypothesis that the corneal overnight swelling response (ONSR) is a predictor of ocular complications in contact lens extended wear (EW). METHODS The Berkeley Contact Lens Extended Wear Study (CLEWS) was a randomized, concurrently controlled clinical trial in which more than 200 subjects in EW with rigid gas-permeable (RGP) lenses were observed for 1 year. After adaptin...

The microflora of the eye has been monitored in 21 patients during a 6-month period to study changes resulting from wear of soft contact lenses. A minimum of 20 cul-de-sac cultures were taken from each patient. Fifty-one percent of cultures taken prior to lens wear were positive for microbial growth, whereas, after lens wear, positive cultures ranged from 14.3% to 30.9" over the 6-month period....

PURPOSE To estimate the incidence of microbial keratitis (MK) associated with overnight corneal reshaping contact lenses and to compare rates in children and adults. METHODS A retrospective study of randomly selected practitioners, stratified by order volume and lens company, was conducted. Practitioners were invited to participate and those agreeing were asked to provide deidentified patient...

Keratoconus is the most common corneal distrophy. It's a noninflammatory progressive thinning process that leads to conical ectasia of the cornea, causing high myopia and astigmatism. Many treatment choices include spectacle correction and contact lens wear, collagen cross linking, intracorneal ring segments implantation and finally keratoplasty. Contact lenses are commonly used to reduce astig...

We examine a mathematical model describing the behavior of the precontact lens tear film of a human eye. Our work examines the effect of contact lens thickness and lens permeability on the film dynamics. Also investigated are gravitational effects and the effects of different slip models at the fluid-lens interface. A mathematical model for the evolution of the tear film is derived using a lubr...