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Biomedical subjects

P B Donzis

Publications and source records attributed to P B Donzis.

At least 19 recordsLinked to original sources

Corneal ulcer associated with contamination of aerosol saline spray tip.

PURPOSE: To report a complication of aerosol saline use in a contact lens wearer. METHODS: Case report. A 57-year-old woman who used soft contact lenses on an extended-wear basis developed a unilateral Pseudomonas corneal ulcer associated with the use of preservative-free aerosol saline. RESULTS: The solution inside the aerosol can was free of microbial contamination. The spray tip, however, was contaminated with P aeruginosa. CONCLUSIONS: Aerosol spray cans may minimize contamination of the solution inside the can. The spray tip is still susceptible to microbial contamination, especially with continued use of the solution over an extended period of time.

Aerosols↗

Visual field loss resulting from cervical chiropractic manipulation.

PURPOSE: To report a complication of chiropractic cervical manipulation. METHOD: Case report. A healthy 39-year-old woman developed sudden left peripheral visual field loss after chiropractic neck manipulation. RESULTS: Visual field testing disclosed a left superior homonymous hemianopsia. A magnetic resonance imaging scan performed the day of the event disclosed acute infarction of the ventromedial aspect of the inferior right occipital lobe. CONCLUSION: Cerebral infarct may occur as a result of chiropractic neck manipulation.

Acute Disease↗

Luminance contrast and colour contrast related errors in pseudoisochromatic plate identification.

PURPOSE: To determine whether differences in luminance contrast and colour contrast are factors in failing to identify American Optical pseudoisochromatic plates (AOPP). METHODS: We studied two groups of subjects. In 20 normal test subjects with no errors on the AOPP we used cross-polarising filters to darken and then gradually increase perceived luminance of the AOPP until these normal subjects correctly identified the plate. In a second group, to evaluate the relationship between a luminance contrast sensitivity score using Arden plates and AOPP identification, we tested 37 non-colour-deficient subjects who missed zero to five of the AOPP of low colour and luminance contrast (plates 9-12, 15). RESULTS: Using the cross-polarising filters, we found five plates that required more light to identify (plates 9-12, 15). In the second experiment, we found a significant relationship between the number missed of these five AOPP plates and a decrease in contrast sensitivity (r = 0.91, p < 0.001, Spearman correlation coefficient). CONCLUSION: Errors in AOPP colour plate detection may be due to loss of ability to perceive colour contrast and possibly luminance contrast.

Adult↗

Successful medical management of Acanthamoeba keratitis.

Seven patients with documented Acanthamoeba keratitis were treated with prolonged and intensive triple antiamoebic therapy consisting of topical neomycin-polymyxin B-gramicidin, propamidine isethionate 0.1%, and miconazole nitrate 1%. Additionally, five patients were treated with topical corticosteroids. Six of seven patients were cured of Acanthamoeba keratitis with medical therapy alone, one patient required therapeutic penetrating keratoplasty to eradicate the infection. Two patients underwent penetrating keratoplasty to improve their vision after medical therapy. Our series differs from previous reports in that triple antiamoebic therapy was used in all seven patients and was successful in both early and advanced cases of Acanthamoeba keratitis. Prolonged and intensive topical therapy with these three antiamoebic drugs may be an effective mode of therapy for Acanthamoeba keratitis.

Administration, Topical↗

Heerfordt syndrome: a cause of facial paralysis.

Heerfordt syndrome is an unusual manifestation of systemic sarcoidosis and is characterized by parotitis, uveitis, and facial nerve paralysis. A case is presented and the clinical manifestations are discussed. Angiotensin converting enzyme assays along with tissue biopsy demonstrating noncaseating granulomas confirm the diagnosis.

Diagnosis, Differential↗

Ocular effects and detection in tears of aerosolized intranasal cocaine and fluorescein.

Ocular effects of intranasal cocaine were investigated. Twenty-nine outpatients from an otolaryngology clinic received 1 mL of aerosolized cocaine 4% (40mg) in each nostril. Intraocular pressure, corneal sensitivity, pupil size, and tear cocaine concentration were assessed before and after cocaine administration. Pupil size was unchanged; intraocular pressure increased in 75% of patients (not statistically significant). Corneal sensitivity decreased by 11% (P less than .05). Cocaine, however, was not detectable in tears using high-performance liquid chromatography. Since corneal sensitivity decreases after intranasal cocaine administration, it may travel retrograde through the nasolacrimal duct. In addition, three pathways of pharmacologic absorption using fluorescein were explored because of its ease of detection. We measured tear fluorescein concentrations in five patients undergoing intravenous angiograms with fluorescein 25% and in six patients who received aerosolized fluorescein 2% intranasally. Fluorescein concentration was 29 times higher per mg dose in intranasal subjects. This finding suggests that reflux occurs through the nasolacrimal duct.

Administration, Intranasal↗

Corneal ulcers associated with disposable hydrogel contact lenses.

Four patients developed corneal ulcers associated with the use of disposable extended-wear hydrogel contact lenses. Bacteria were recovered from corneal ulcers in three of the patients. Three patients discarded their contact lenses after ten or more days of extended wear; the corneal ulcers in these patients developed toward the end of the wearing cycle. The fourth patient removed her contact lenses every two days for cleaning and disinfection and discarded them for a new pair on a weekly basis. Improper lens hygiene was noted in only one patient. All corneal ulcers responded to antibiotic treatment. In three patients visual acuity returned to normal, but scarring of one patient's cornea resulted in a visual acuity of 20/60.

Adult↗

Microbial analysis of contact lens care systems contaminated with Acanthamoeba.

We analyzed bacterial and fungal contamination within the contact lens care systems of ten patients who had Acanthamoeba detected within their care systems. Seven patients had Acanthamoeba keratitis, one had Pseudomonas keratitis, and the remaining two were asymptomatic. Gram-negative bacteria were found in all ten care systems, and Pseudomonas was found in six. Bacillus species, the only gram-positive bacteria isolated, were found in five systems. Fungi were isolated in six care systems. The use of homemade saline and the two-cup method of peroxide disinfection were associated with microbial contamination. Acanthamoeba organisms were found only in contact lens cases or solutions that also had bacterial and in many cases fungal contamination, suggesting that the presence of bacterial and fungal contamination within the contact lens care system may be an important element for the survival and growth of Acanthamoeba.

Acanthamoeba↗

Bacillus keratitis associated with contaminated contact lens care systems.

We examined two soft contact lens wearers who developed keratitis associated with Bacillus contamination of their contact lens care systems. Patient 1 developed a corneal ulcer caused by B. subtilis, and Patient 2 demonstrated multiple, diffuse, punctate corneal epithelial opacities associated with B. cereus contamination in the contact lens and lens case compartment. The contact lens cases of both patients contained Bacillus spores that survived multiple heat disinfection treatments. Three different contact lens chemical disinfection systems used for the minimum recommended time failed to kill the Bacillus organisms.

Adult↗

Light-induced maculopathy and cystoid macular edema.

We present two patients with paramacular burns induced by the operative light microscope. In one case there was associated cystoid macular edema. Of the 34 total reported cases of paramacular burns, there have been only two cases of cystoid macular edema. Thus, although the total number of reported cases of light-induced maculopathy is small, this disorder does not appear to predispose to cystoid macular edema. Loss of visual acuity is mainly caused by the proximity of the burn to the fovea.

Aged↗

Stromal corneal scar following YAG capsulotomy.

The case of a 70-year-old patient who suffered inadvertant YAG laser burns to the central corneal stroma is presented. Although focal stromal scarring resulted, no endothelial damage or corneal decompensation was noted, and the patient was asymptomatic.

Aged↗

Microbial contamination of contact lens care systems.

We examined the contact lens care systems of 100 asymptomatic patients who used hard or soft contact lenses for correction of refractive errors for the presence of bacteria, fungi, Acanthamoeba, and endotoxin. Of 100 patients, 52 had contaminated contact lens care systems. Sixteen of 126 bottles (13%) of commercial contact lens care solutions were contaminated. Contaminated commercial solutions were opened and used for a longer period of time than uncontaminated solutions. Contamination was not found in bottles of preserved commercial solutions that were opened and used for less than 21 days. All 12 bottles of homemade saline were contaminated with bacteria, and Acanthamoeba was isolated from two of these bottles. Pseudomonas was found in the care systems of 12 patients. Bacillus species, which form spores resistant to heat, were found in the care systems of seven patients. Endotoxin, which is also resistant to heat, was detected in nine of 35 care systems (26%) tested. Potential pathogens were isolated from the conjunctiva of six patients.

Adolescent↗

Prediction of aphakic refractive error in children.

Formulas created to predict the optical requirements of the aphakic eye have been tested mainly in adult eyes. The accuracy of these formulas in shorter pediatric aphakic eyes was examined using retrospective analysis of 17 aphakic pediatric patients. The Sanders-Retzlaff-Kraff contact lens formula, used previously to predict required lens powers for epikeratophakia, consistently underestimated the required aphakic correction in the shorter eyes, which may have been responsible in part for the large undercorrections obtained previously in patients under one year of age. The Hoffer-Colenbrander and Binkhorst theoretical formulas, Donzis-Kastl-Gordon percentage change formula, and a linear regression formula derived from the present data (LIN), were significantly more accurate. The differences between these formulas were not significant. The use of one of these formulas should facilitate prediction of required epikeratophakia lenticule power or intraocular lens power in young children.

Aphakia, Postcataract↗

Keratitis and contact lens wear: a review.

The most feared complications of contact lens wear are keratitis and infectious corneal ulceration. This article first defines terms for the clinical practitioner, and then describes and illustrates clinical presentation and management.

Bacterial Infections↗

Myopia associated with retinopathy of prematurity.

A complete analysis of the components of refractive error was performed on ten eyes of five patients with myopia and retinopathy of prematurity (ROP). In comparison to an age-matched control group, these eyes exhibited both lenticular and axial myopia. Only the high crystalline lens powers, which ranged from 22.20 to 44.13 diopters (D) (mean value, 31.27 D), were found to be statistically significant. In two patients, only one eye had high myopia. The lens power in these eyes was approximately 11 D more powerful than the lens of the fellow eye. Further investigation into the ocular changes induced by prematurity and abnormal oxygen metabolism is needed to determine the reason for the high degree of lenticular myopia.

Child↗