PubMed Health⌕ Search

Biomedical subjects

I F Wessels

Publications and source records attributed to I F Wessels.

At least 19 recordsLinked to original sources
PubMed1999

The photic sneeze reflex and ocular anesthesia.

BACKGROUND AND PURPOSE: Intravenous sedation to minimize discomfort from local anesthetic injection has many potential complications including severe involuntary sneezing (i.s.). This prospective study evaluates the occurrence of i.s. and a history of photic sneezing (p.s.). METHODS AND MATERIALS: All patients receiving local anesthesia (retrobulbar or periocular injections) after intravenous thiopentone for eye surgery during eight months were asked about p.s. and observed for i.s. RESULTS: The 557 patients (40% males) had a mean age of 69.9 years and 14% recalled p.s. (29.5% males). I.s. developed in 5.2% of the 557. Only 7.6% of those with p.s. developed i.s. After periocular injections 23.8% developed as compared to 4.5% after retrobulbar injections. (P < 0.001). There was no relationship between p.s. and i.s. (p = 0.43). CONCLUSION: I.s. is not linked to p.s., with males and females at equal risk for either. I.s. is more common after periocular injections.

Adolescent↗
PubMed1998

Salvaged viscoelastic reduces irrigation frequency during cataract surgery.

A more viscous solution may decrease the need for frequent irrigations to maintain a clear cornea during cataract surgery. Fifty-four consecutive cataract patients were prospectively randomized to receive a drop of viscoelastic or saline on the cornea at the start of surgery. The surgical scrub nurse was instructed to irrigate only when the cornea appeared hazy or at the surgeon's request. The number of irrigations, ultrasound time and energy, and surgery times were compared using the Student's t test. Only one ampoule of viscoelastic was used for each case. When the patients who received viscoelastic were compared with the patients who received saline, the mean numbers of irrigations were 2 and 18, whereas the mean numbers of irrigations per minute were 0.17 and 1.21, highly significant (P < .0001) differences. The duration of surgery, ultrasound time, and ultrasound energy were less with viscoelastic, but were not statistically significant. Viscoelastic on the cornea reduces the frequency of irrigation without increasing cost.

Aged↗
PubMed1998

Hook and loop fastener on loose prisms assists in measuring ocular deviation.

It is difficult to hold a pair of loose prisms in one hand. Doing so can lead to inaccuracy, which worsens with large-angle exotropia or vertical deviations. The authors applied a self-adhesive hooked Velcro (Velcro Sticky Back Tape, Velcro USA Inc., Manchester, NH) strip to the base and the top of loose prisms. They applied the complementary looped Velcro to a wooden bar. As a result, a pair of prisms could be suspended horizontally and/or vertically while being held in one hand. Forty consecutive patients undergoing strabismus surgery without adjustable sutures were retrospectively studied to evaluate the accuracy of this method. Clinical use confirmed its ease and convenience. Of 19 patients with exotropia and 15 patients with esotropia (mean ages 41.9 and 15.7 years, respectively; mean deviations 44.7 and 49.8 D, respectively), 4 patients with abducens paralysis, and 2 patients with trochlear palsies, 1 surgery achieved less than 10 D of residual deviation in all but 2 (5.9%). This simple, inexpensive system can assist with the clinical evaluation of ocular deviation.

Adolescent↗
PubMed1998

Rabbit Streptococcus pneumoniae keratitis model and topical therapy.

PURPOSE: To develop a model for experimental Streptococcus pneumoniae keratitis and to evaluate the chemotherapeutic efficacy of 12 common topical antibiotics in vivo. METHODS: Five-hundred (CFUs of log-phase S. pneumoniae were injected into the central corneal stroma of 36 eyes of 18 rabbits. After 0, 4, 8, 16, 24, and 48 hours, the in vivo growth was assayed as the CFU per cornea. Epithelial removal (to promote antibiotic entry and mimic human keratitis) was evaluated. Disc or tube dilution verification of the sensitivity or resistance of three S. pneumoniae strains was performed: a penicillin sensitive ("S"), an intermediate sensitive ("I"), and a resistant ("R") strain. Keratitis was established with S. pneumoniae "S" in 65 eyes, S. pneumoniae "I" in 107 eyes, and S. pneumoniae "R" in 78 eyes. Sixteen hours later, control corneas were harvested and the epithelium removed from treatment corneas. Every half hour saline, penicillin, gentamicin, bacitracin, ciprofloxacin, ofloxacin, erythromycin, vancomycin, ceftriaxone, cefotaxime, or chloramphenicol was applied for 5 hours. One hour later CFUs/cornea were assayed. RESULTS: After 24 hours, S. pneumoniae "S" and "I" had proliferated to 9.18+/-6.65 x 10(6) CFUs and 9.26+/-6.90 x 10(6) CFUs. Epithelial removal at 16 hours was not significant. The in vitro antibiotic sensitivity was as expected. However, in vivo, penicillin, gentamicin, or cefazolin sterilized S. pneumoniae "S." S. pneumoniae "R" responded best to fortified gentamicin with or without vancomycin; all others antibiotics were significantly less effective (P < 0.001). CONCLUSIONS: A small intracorneal S. pneumoniae inoculum in rabbit corneas grew and was maintained for 24 hours (with epithelial removal) to provide a model for testing antibiotic sensitivity in vivo. Topical penicillin is best for treating keratitis from penicillin-sensitive S. pneumoniae, whereas topical gentamicin or a combination of gentamicin and vancomycin was most effective against penicillin-resistant S. pneumoniae.

Administration, Topical↗
PubMed1998

The effect of vehicle on corneal penetration of triturated ketoconazole and itraconazole.

BACKGROUND AND OBJECTIVES: Triturated (crushed and suspended) ketoconazole has been recommended for the treatment of fungal keratitis when commercial antifungal eyedrops are unobtainable. The authors evaluated the in vivo corneal stromal concentration with different vehicles in the eyes of adult rabbits. MATERIALS AND METHODS: Ketoconazole and itraconazole tablets were triturated to 20 mg/ml in four vehicles: polyvinyl alcohol (PVA), boric acid, olive oil, and balanced salt solution (BSS). Six eyes (deepithelialized for better penetration) received one drop every 15 minutes for 2 hours. A yeast overlay bioassay of extracts determined the stromal concentration. RESULTS: Itraconazole in BSS, olive oil, PVA, and boric acid produced inhibition zones of 17.3, 15.6, 15.4, and 13.2 mm, respectively. Ketoconazole produced inhibition zones of 35.9, 39.4, 41.8, and 44.7 mm, respectively. From a standard curve, the concentrations of ketoconazole in tissue were 512, 773, 1221, and 1492 micrograms/g, respectively. CONCLUSION: The vehicle that is used to triturate antifungals affects the tissue concentration. This may have an impact on fungal keratitis therapy.

Animals↗
PubMed1996

Improving the sensitivity of the OKP visual field screening test with a blue stimulus on a dark background.

The standard oculokinetic perimetry test (OKP) was modified to present a light blue stimulus on a dark background (MOKP) to determine whether the sensitivity and specificity for detecting glaucomatous visual field loss could be improved. Thirty-five adult glaucoma patients (70 eyes) self-administered both tests and the results were correlated with the loss of retinal sensitivity on the Octopus IV program 38. The MOKP detected 18% more true scotomatous loci (more than 15 dB loss of attenuation) than the standard OKP (p < 0.0001). The gain was due to 37% fewer false negatives (p < 0.0001), but with a doubling of the false positives rate (p < 0.049). With a disease prevalence of approximately 2%, the MOKP and OKP would respectively miss 15% or 30%, and include 14 or 9 normals for each diseased individual. This relatively simple modification may further improve the OKP for detecting glaucoma.

Adolescent↗
PubMed1996

Mechanized keratomicropigmentation: corneal tattooing with the blepharopigmentor.

BACKGROUND AND OBJECTIVE: A mechanized micropigmentor with a triple prong tip was used to tattoo two corneas for cosmetically unacceptable blemishes. PATIENTS AND METHODS: Two adult patients with cosmetically disfiguring corneal blemishes in sightless eyes requested cosmetic improvement. With a mechanized micropigmentor, appropriate pigment was directly inoculated through the epithelium. RESULTS: After 2 and 3 years of follow-up, respectively, there have been no complications and there has been minimal fading. CONCLUSION: This mechanical device facilitates many more penetrations to introduce pigment, with a more uniform depth than can be achieved by freehand methods.

Adult↗
PubMed1996

Lidocaine-prilocaine cream for local-anesthesia chalazion incision in children.

BACKGROUND: Chalazia are not uncommon in children. If conservative therapy for them fails, incision and drainage are necessary and usually require a general anesthetic, which increases costs and risks. PATIENTS AND METHODS: Five children (3 to 8 years old) had a eutectic mixture of lidocaine and prilocaine applied to the skin of the eyelid for 1 hour. Then local anesthetic was injected into the same site. RESULTS: The local anesthetic injection was painless, permitting successful incision and drainage in all cases. CONCLUSION: Lidocaine-prilocaine cream permits local anesthetic injection into the eyelids, facilitating office-based management of chalazia in children.

Administration, Topical↗
PubMed1995

Treatment of idiopathic macular holes by induced posterior vitreous detachment.

PURPOSE: To determine if an expansile gas bubble can relieve vitreofoveal traction without vitrectomy by inducing a posterior vitreous detachment (PVD) in eyes with an idiopathic impending or full-thickness macular hole (stages 1-3). The status of the impending and full-thickness macular holes after gas injection and tamponade also was studied secondarily. METHODS: Eighteen patients participated in this pilot study. Eleven patients with an impending macular hole (stages 1A and 1B) and seven patients (8 eyes) with a full-thickness macular hole (stages 2 and 3) received gas injections and prospectively were followed for an average of 15.6 months (range, 3-42 months). RESULTS: A complete PVD was achieved in 18 of 19 eyes without a prior PVD within 2 to 9 weeks after gas injection. Ten of the 11 impending holes (all 7 had stage 1A holes; 3 of 4 had stage 1B holes) resolved after gas injection. After gas tamponade, three of six early full-thickness (stage 2) macular holes closed. None of the stage 3 macular holes closed after gas injection. The mean best-corrected visual acuity of the successful eyes was 20/32. There were no major complications. CONCLUSION: An expansile gas bubble consistently can induce a PVD in aging eyes. The ability of an expansile gas bubble to induce a PVD with minimal morbidity and expense may have clinical applications for macular hole therapy. Impending macular holes may resolve and some early full-thickness (stage 2) macular holes may close after gas injection and tamponade without vitrectomy. The efficacy and safety of this procedure may be evaluated further in the context of a carefully designed prospective and randomized study for selected patients with an idiopathic impending or early macular hole.

Aged↗
PubMed1994

Comparison of topical ciprofloxacin to conventional antibiotic therapy in the treatment of experimental Pseudomonas aeruginosa keratitis.

We evaluated the efficacy of topical ciprofloxacin (3.0 mg/ml) in the treatment of experimental Pseudomonas aeruginosa keratitis in 60 rabbits. We compared ciprofloxacin treatment with double drug therapy consisting of tobramycin (13.6 mg/ml) plus polymyxin B (25,000 U/ml) or carbenicillin (6 mg/L). Two strains of P. aeruginosa were used. One was a strain well characterized for use in experimental Pseudomonas keratitis (ATCC organism 27853); the second was an organism from a patient with a Pseudomonas corneal ulcer. Rabbits were treated for 16 h, after which the corneas were excised, homogenized, and plated serially for residual colony-forming units. Both organisms responded significantly better to topical off-the-shelf ciprofloxacin than to therapy with two conventional antipseudomonal fortified antibiotic drugs (p < or = 0.0001).

Administration, Topical↗
PubMed1994

Guidelines for overseas eye surgery expeditions using short-term volunteers. Surgical Eye Expeditions international.

Many developing countries face the overwhelming problem of addressing preventable and curable blindness. United States-based ophthalmologists can make important contributions in this regard by volunteering to teach and deliver eye care overseas. However, there are a number of potential risks and difficulties. Surgical Eye Expeditions (SEE) International has developed a logistical outline and planning checklist designed to minimize or avoid such problems. Critical components include a firm timetable, advanced planning, advance contact with a local ophthalmologist or organization, and a thorough understanding of the importance of adapting to the needs of other cultures. With a little planning, the average philanthropic ophthalmologist can make major contributions to individuals and communities in developing nations.

Developing Countries↗
PubMed1993

Modifying a Polaroid camera for close-up documentation.

A standard plus-three-diopter trial lens held in front of the objective lens of an inexpensive Polaroid camera produces close-up photographs of acceptable quality. This simple technique can be used to inexpensively document indications for plastic surgery and provide medicolegal documentation. The 23-millimeter-diameter trial lens provided acceptable resolution, but reduced depth of field; it must be well-centered to avoid vignetting.

Forensic Medicine↗