Evaluation Of A New Silicone-Methane Polymer Contact Lens

A new gas permeable contact lens is produced using a solid silicone core and a plasma polymer surface. This surface is hydrophilic and impermeable to macromolecules. The surface characteristics of this lens were compared with the surface characteristics of available silicone contact lenses. We found that in contrast to our lens, the silicone contact lenses lost their hydrophilic surface with time. In addition, they are permeable to lipid dyes, eg, Sudan red. © 1983 Arch Ophthalmol All rights reserved

Bacterial transmission from contact lenses to porcine corneas:An ex vivo study

PURPOSE. To quantify the transmission to ex vivo porcine eyes of Staphylococcus aureus 835 and Pseudomonas aeruginosa 3 from three types of contact lenses - one daily wear and two extended wear - differing in hydrophobicity and roughness.METHODS. One daily wear lens (etafilcon) and two extended-wear lenses (one lotrafilcon A and one balafilcon A) were inoculated in a bacterial suspension for 30 minutes and then placed on ex vivo porcine eyes. After 16 hours of contact between lens and eye, confocal laser scanning microscopy was used to determine the number of bacteria on the lens and cornea for the calculation of transmission percentages.RESULTS. Transmission percentages were significantly different for both bacterial strains from an etafilcon A lens and balafilcon A lens (P = 0.006 and 0.04, respectively). Percentages varied from 51% to 68% for the hydrophobic P. aeruginosa and from 54% to 82% for the hydrophilic S. aureus strain, depending on the contact lens involved. Both strains were transferred the least from the most hydrophilic and roughest lens made of lotrafilcon A, although the difference was only statistically significant for S. aureus.CONCLUSIONS. Bacterial transmission to the porcine cornea differed in the various types of contact lenses and was least in the hydrophilic and rough lens type.</p

A clinical comparison of three hydrophilic contact lenses on dry eye patients

This study was designed to evaluate three hydrophilic contact lens materials for comfort, dryness and overall satisfaction on subjects with and without subjective dry eye. The lenses evaluated were Acuvue, Proclear and SaturEyes. Thirty-seven subjects wore each pair of contact lenses for one week. Lens evaluations were reported via questionnaire. The subjects without dry eye rated all three lenses about the same for comfort, dryness and overall satisfaction. Participants with dry eye symptoms rated the lenses the same for comfort and overall satisfaction but preferred SaturEyes when assessing dryness

Adhesion of Pseudomonas aeruginosa and Staphylococcus epidermidis to silicone-hydrogel contact lenses

Purpose. The purpose of this study is to compare the adhesion capabilities of the most important etiologic agents of microbial ocular infection to the recently available silicone– hydrogel lenses with those to a conventional hydrogel lens. Methods. In vitro static adhesion assays of Pseudomonas aeruginosa 10,145, Staphylococcus epidermidis 9142 (biofilm-positive), and 12,228 (biofilm-negative) to two extended-wear silicone– hydrogel lenses (balafilcon A and lotrafilcon A), a daily wear silicone– hydrogel lens (galyfilcon A) and a conventional hydrogel (etafilcon A) were performed. To interpret the adhesion results, lens surface relative hydrophobicity was assessed by water contact angle measurements. Results. P. aeruginosa and S. epidermidis 9142 exhibited greater adhesion capabilities to the extended wear silicone– hydrogel lenses than to the daily wear silicone– and conventional hydrogel lenses (p < 0.05). No statistical differences were found between the adhesion extent of these strains to galyfilcon A and etafilcon A. The biofilm negative strain of S. epidermidis adhered in larger extents to the silicone– hydrogel lenses than to the conventional hydrogel (p < 0.05), but in much lower amounts than the biofilm-positive strain. The water contact angle measurements revealed that the extended wear silicone– hydrogel lenses are hydrophobic, whereas the daily wear silicone– and conventional hydrogel lenses are hydrophilic. Conclusions. As a result of their hydrophobicity, the extended wear silicone– hydrogel lenses (lotrafilcon A and balafilcon A) may carry higher risk of microbial contamination than both the hydrophilic daily wear silicone– hydrogel lens, galyfilcon A and the conventional hydrogel lens, etafilcon A.Fundação para a Ciência e a Tecnologia (FCT

A comparison of Optisoap versus commercial soap in preventing protein deposition on hydrophilic contact lenses

This study compared the effectiveness of Optisoap versus other commericial hand soaps in preventing protein deposition of hydrophilic contact lenses due to soap residues. Twelve clean lenses were halved, treated with Optisoap or a commercial soap, and placed in a protein solution. The lenses were inspected for protein deposits after thirty and sixty minutes. No significant difference was found between the Optisoap or the commercial soaps

Bacterial populations on silicone hydrogel and hydrogel contact lenses after swimming in a chlorinated pool

Purpose: A number of reports have indicated an association between swimming with contact lenses and subsequent eye infection. This study tests whether a hydrophilic contact lens worn while swimming accumulates bacteria present in the water. It was of interest to determine if lens type (silicone hydrogel versus hydrogel) affected the result. Methods: Fifteen healthy non-contact lens wearers swam for 30 minutes with a silicone hydrogel lens (Purevision) on one eye and a hydrogel lens (Acuvue 2) on the other. Lenses were removed aseptically and placed in sterile vials five minutes after the subjects left the water. Microbial growth was enumerated for total numbers of colonies and categorized by species present. Numbers of colonies were compared between the two lens groups, and with a water sample taken from the pool at the time of the experiment. Eight of the subjects returned on a different day and wore new lenses for thirty minutes under normal room conditions. Results: Two lenses were lost while swimming. 27 of the remaining 28 lenses worn while swimming showed colonization, principally with Staphylococcus epidermidis, which was also by far the most common species identified from the water itself. Small numbers of Staphylococcus aureus and Streptococcus salivarus were also present in both the water and on the lenses. Numbers of colonies varied among subjects (range 0-230), but no differences were observed between the two lens groups. Lenses removed after thirty minutes of wear without swimming were mostly sterile, with 3 of the 16 lenses showing just two colonies each. Conclusion: It appears that wearing a hydrophilic lens while swimming allows accumulation of microbial organisms on, or in, the lens, regardless of lens material. Swimmers should be advised to wear tight fitting goggles if lenses are worn while swimming, and thorough disinfection of the lenses prior to overnight wear seems prudent

A comparison of weekly cleaners on hydrophilic contact lenses

This study examined the effects of three weekly soft lens cleaners on deposits found on hydrophilic lenses. Lenses cleaned by Allergan Soflens Enzymatic(AE), Alcon Optizyme(AO) and Barnes Hind(BH) weekly cleaner were submitted to Allergan Pharmaceuticals for soft lens deposit identification. Results indicated a reduction of deposits on 30.8% of the lenses cleaned with AO, 41 .0% of those cleaned with AE and 43 .6% of those cleaned with BH

A clinical evaluation of the Wesley-Jessen astigmatic hydrophilic Dura-Soft contact lens (Phemecol)

Fifteen patients were fit with the Dura-Soft™ (Phemecol) hydrophilic astigmatic contact lenses. Due to length of time to receive the lenses only three patients were considered full time wearers at the time of publication. One patient was taken off the study due to physiological incompatibility to the lens. Of the thirty lenses ordered, sixteen were reordered. Stx were changed for spherical power, three for cylinder power, three for cylinder axis, three were ordered flatter than verified basecurve, twelve were ordered steeper than verified basecurve, and for twelve lenses the prism component was changed. Many of the new lenses ordered required more than one lens variable changed

A survey of patient reaction to hydrophilic contact lenses

A survey of patient reaction to hydrophilic contact lense