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Biomedical subjects

I F Wessels

Publications and source records attributed to I F Wessels.

41 records · Page 3Linked to original sources
PubMedDate not supplied

Open drops in ophthalmology offices: expiration and contamination.

OBJECTIVE: To determine the relationship between eye drop use and contamination rate in ophthalmology offices. DESIGN: Following permission request, open bottles were examined and the nozzle tip and one drop of content was cultured on solid media. OUTCOME MEASURES: Drug category, volume, weight compared to full, clean legible label, expiration date; 2 or more bacterial colonies along the inoculation site. RESULTS: In 18 offices, of 1,485 open bottles (mean 12.2, range 4 to 23 per lane) on average 19.8% (range 0% to 88%) were expired (16.2 of 82.5 bottles per office). The frequency of occurrence (%) and expiration (%E) were 40.3% cycloplegics (19.4%E); 16.4% glaucoma (33.7%E); 10.8% anesthetics (8.8%E); and 4% steroids (8.8%E; or 42.2%E including one outlier). Most likely expired were glaucoma (P < 0.001); small 2-3 ml (P < 0.02), nearly empty (P < 0.05), or dirty (P < 0.001) bottles. Only one (5 ml cyclopentolate, not expired) grew a Micrococcus (0.07%). CONCLUSIONS: Drops in ophthalmology offices may be expired but are not contaminated.

Drug Contamination↗
PubMedDate not supplied

Adjustment of single continuous suture to control astigmatism after penetrating keratoplasty.

The presence of high amounts of regular and irregular astigmatism after penetrating keratoplasty has been a major challenge for corneal surgeons. We have devised a technique of suture adjustment which redistributes the tension in a single continuous 10-0 nylon suture according to keratometric findings and overcomes some of the limitations of other published methods for reducing penetrating keratoplasty astigmatism. Suture adjustment is performed at the slit-lamp microscope using topical anesthesia, from as early as the first postoperative day. The effects are controllable, reversible, stable, and can achieve relaxation or tightening of any meridian. Of 330 consecutive eyes undergoing penetrating keratoplasty, 205 required and underwent one or more suture adjustments. The mean keratometric astigmatism after suture adjustment was 2.87 D (SD = 1.87), compared to a preceding consecutive series of 136 eyes without suture adjustment with 4.80 D (SD = 3.13) mean astigmatism (P less than 0.0001). This effect persisted even when the suture had to be removed (P less than 0.0001). Infection did not occur. Only five eyes (2.4%) experienced a broken suture, which was readily spliced. We recommend adjustment of a single continuous suture, when moderate to severe astigmatism is present after a penetrating keratoplasty.

Adult↗
PubMedDate not supplied

Microbiologic evaluation of a hydrogen peroxide sterilization system.

The reliability of chemical sterilizers (acetone and/or 30-percent hydrogen peroxide at 25 degrees C and at 60 degrees C) was tested against Bacillus subtilis inoculated onto glass slides, commercial biological indicator discs (Bacillus stearothermophilus and B. subtilis), and B. subtilis spore survival. Acetone alone was not sporicidal. Hydrogen-peroxide-sterilized glass slides were sterile after 5 minutes. The indicator discs required 25 minutes at 25 degrees C, and less than 3 minutes at 60 degrees C (P < .0001). The D value of B. subtilis in 27-percent hydrogen peroxide at 25 degrees C is 2 minutes, with z values of 22 degrees C and 26 degrees C at 25 degrees C and 40 degrees C, respectively. For delicate instruments, a 30-percent peroxide solution followed by an acetone rinse provides an effective alternative to classic heat sterilization.

Acetone↗