Search PubMed⌕ Search

Biomedical subjects

R K Forster

Publications and source records attributed to R K Forster.

At least 37 records · Page 2Linked to original sources
PubMed1988

Exogenous fungal endophthalmitis.

The authors report 19 cases of exogenous fungal endophthalmitis managed between 1969 and 1986. These developed after ocular surgery (5 cases), after trauma (6 cases), by intraocular spread from fungal keratitis (4 cases), after therapeutic keratoplasty for keratitis (3 cases), and by spontaneous infection of a filtration bleb (1 case). The diagnosis of endophthalmitis was made from 3 days to 4 months after surgery or trauma. In patients with preexisting keratitis, endophthalmitis was noted 2 weeks to 5 months after the onset of keratitis. Seventeen cases were caused by filamentous fungi; two were caused by yeast. Fusarium (6 cases) and Acremonium (3 cases) accounted for approximately one half of the isolates. Forty-two percent of the patients recovered 20/400 or better acuity (3 of 5 postoperative cases, 4 of 6 trauma cases, and 1 of 4 keratitis cases). The clinical and microbiologic features of these cases are presented, and recommendations for management are offered.

Electroretinography↗
PubMed1987

Branhamella catarrhalis keratitis.

Branhamella catarrhalis, formerly known as Neisseria catarrhalis, has structural similarities to Neisseria gonorrhoeae, but is generally considered to be nonpathogenic. We studied the clinical and laboratory data of four previously reported cases and six additional cases of B. catarrhalis keratitis. All patients had a predisposing ocular or systemic condition, or both. There were various clinical characteristics, but in most cases the infiltrate occurred in the central or paracentral cornea. A prompt response to treatment with a cephalosporin and aminoglycoside antibiotic was noted in all cases. Two patients had corneal perforations, which probably resulted from a delay in treatment. Gram-negative diplococci from corneal scrapings may not necessarily represent N. gonorrhoeae.

Adolescent↗
PubMed1987

Zonular dialysis during extracapsular cataract extraction in pseudoexfoliation syndrome.

Five patients with pseudoexfoliation syndrome (PES) and glaucoma developed extensive zonular dialyses during extracapsular cataract extractions. Weakness of the lens zonules or their attachments to the ciliary processes, which has been described in association with PES, may explain this complication. We believe that patients with PES are at particular risk for developing large zonular dialyses during extracapsular surgery. Preoperative phakodonesis, anterior chamber depth asymmetry, and excessive lens movement during the anterior capsulotomy should alert the surgeon to this problem.

Aged↗
PubMed1987

Intravitreal vancomycin. Retinal toxicity, clearance, and interaction with gentamicin.

Some of the gram-positive isolates from exogenous bacterial endophthalmitis cases treated at our institution have been found to be resistant to either cefazolin sodium, gentamicin sulfate, or both. However, all of these isolates have been sensitive to vancomycin. These findings prompted us to reevaluate the retinal toxicity and clearance of intravitreal vancomycin in pigmented rabbits. Doses up to 2 mg were found to be nontoxic in phakic and aphakic-vitrectomized eyes. Clearance was determined in phakic and aphakic-vitrectomized rabbit eyes with or without intact lens capsules. The antibiotic was cleared most slowly in phakic eyes. Aphakic-vitrectomized eyes without an intact lens capsule cleared antibiotic most rapidly, while aphakic-vitrectomized eyes with intact capsules exhibited an intermediate clearance rate. In addition, the interaction between vancomycin and gentamicin on gram-positive endophthalmitis isolates was found to be additive or synergistic depending on the bacterial species. Based on these data, we recommend the combination of vancomycin and an aminoglycoside as the initial antibiotic therapy for exogenous bacterial endophthalmitis.

Animals↗
PubMed1987

Amelioration of experimental lipid keratopathy by photochemically induced thrombosis of feeder vessels.

The photochemical interaction between intravenously injected rose bengal dye and 514.5-nm argon laser irradiation was employed to initiate permanent thrombotic occlusions in the corneal neovasculature of rabbit eyes with experimentally induced lipid keratopathy. This photothrombotic procedure did not produce corneal edema or polymorphonuclear leukocyte infiltration, as was found in previous studies employing laser-induced photocoagulation. Thus, by means of the new technique, we avoided the formation of additional neovascularization and lipid deposition. Vascular occlusion by photothrombosis, effected with 8.5 times less incident intensity and 27.5 times less total light exposure than with photocoagulation, yielded an average reduction of corneal cholesterol content of 36% as opposed to an increase of 24% found with previous argon laser photocoagulation.

Animals↗
PubMed1987

Control of corneal astigmatism following cataract extraction by selective suture cutting.

We evaluated the ability of selective suture cutting to reduce postoperative corneal astigmatism in 75 eyes of 68 patients who underwent extracapsular cataract extraction with posterior chamber intraocular lens implantation. Keratometric and refractive measurements were obtained before and at selected intervals (3, 6, 10, 26, and 52 weeks) after surgery. The number of sutures cut during the sixth week after surgery was based on the degree of astigmatism (0.00 to 2.00 diopters (D), no sutures cut; 2.25 to 3.00 D, one suture cut; 3.25 to 4.00 D, two sutures cut; greater than or equal to 4.25 D, three sutures cut). Our analysis demonstrated the following: (1) a spontaneous reduction of 0.5 D in surgically induced astigmatism in eyes without suture cutting, (2) an additional reduction of 1.2 D in postoperative astigmatism for each suture cut, and (3) attainment of 75% to 93% of the total effect of suture cutting within four weeks. The final astigmatism one year after surgery had increased by a mean of 0.9 D, exhibited predominantly with-the-rule properties, and showed no significant difference among the four groups of patients. Vector analysis revealed that only small shifts in the axis of astigmatism occurred after suture cutting. A strong correlation between the keratometric and subjective refractive measurements during all postoperative examinations indicated that corneal astigmatism is primarily responsible for postoperative astigmatism.

Astigmatism↗
PubMed1987

Neisseria gonorrhoeae keratoconjunctivitis.

Clinical and laboratory findings of 47 patients with ocular infections secondary to Neisseria gonorrhoeae during a 5 1/2-year period were reviewed. In 16 patients (34%), corneal involvement was noted. Six of these patients had a severe ulcerative keratitis resulting in permanent visual loss and five required surgery for a corneal perforation. Patients with corneal involvement were older and presented later in the course of their disease than patients with isolated conjunctival involvement (P less than 0.005). An out-patient regimen of intramuscular antibiotics (either penicillin, cephalosporin, or spectinomycin [Trobicin]) appeared to be effective for infections limited to the conjunctiva in adults. If a topical antibiotic ointment is used in addition to parenteral antimicrobial agents, the authors' laboratory sensitivities suggest that erythromycin may be the drug of choice.

Acute Disease↗
PubMed1987

Accommodation of an endocapsular silicone lens (Phaco-Ersatz) in the nonhuman primate.

In owl monkeys, as a model of endocapsular cataract extraction, the lens material was removed through a small hole in the capsule and was replaced with a silicone polymeric gel. The ability of this endocapsular implant (Phaco-Ersatz) to accommodate was documented when pilocarpine produced an increase in the curvature of the lens surface and a decrease in the anterior chamber depth, just as occurs with the untouched natural lens. Refinements of the surgical technique are required to achieve a controlled degree of filling of the capsular bag and inhibit postoperative epithelial proliferation on the inner capsular surface.

Accommodation, Ocular↗
PubMed1987

Microbial endophthalmitis resulting from ocular trauma.

Twenty-seven cases of culture-positive endophthalmitis that developed after ocular trauma were reviewed. The intraocular culture specimens showed a virulent microbiologic spectrum with Bacillus sp as the most common isolate (8 eyes). The visual prognosis was poor, with only 22% of patients retaining 20/400 or better vision. This level of vision was achieved in 2 of 22 (9%) bacterial cases and in four of five (80%) fungal cases. Retinal detachment (5 cases) or retinal breaks (2 cases) at the time of the initial injury had a uniformly poor visual prognosis. Postoperative retinal detachment not associated with phthisis bulbi occurred in five eyes, three of which had successful retinal reattachment surgery. Delayed onset retinal detachment after successful initial management of traumatic endophthalmitis had a greater frequency of successful retinal reattachment surgery.

Adolescent↗
PubMed1987

Specular microscopy in aniridia.

Aniridia and the iridocorneal endothelial (ICE) syndromes both are conditions which include abnormalities of the cornea, iris, and progressive iridocorneal adhesions which may result in glaucoma. In order to investigate the similarities between aniridia and the ICE syndromes, we performed specular microscopy of the corneal endothelium in nine patients with aniridia. Morphology and density of the corneal endothelium appeared normal for age. We found no evidence of the beaten metal appearance classically seen on specular microscopy in patients with ICE symptoms. This study did not support either an anatomic or pathogenic relationship between aniridia and the ICE syndromes.

Adolescent↗
PubMed1987

Comparative tonometric measurements of eye bank eyes.

A comparison was made of the accuracy of the Tono-Pen, Pneumatonometer, and Perkins hand-held tonometers by measuring the hydrostatically controlled intracular pressure from 10 to 50 mm Hg in human eye bank eyes. The open stopcock method was used in which the cannulated eye, the hydrostatic pressure controlling column, and a manometer were continuously open to each other. The Pneumatonometer gave accurate results at 50 mm Hg but overestimated the lower intraocular pressures; whereas, the Perkins gave satifactory results at 10 and 20 mm Hg but underestimated higher intraocular pressures. The Tono-Pen displayed the least deviation from the controlled pressure over the entire range studied. Another aspect of this study involved determining that a therapeutic soft contact lens did not have any noticeably adverse effect on the accuracy of the Pneumatonometer and Tono-Pen tonometers.

Contact Lenses, Hydrophilic↗
PubMed1986

Ulcerative keratitis associated with contact lens wear.

A review of 573 cases of ulcerative keratitis cultured at the Bascom Palmer Eye Institute from January 1977 through September 1982 showed that 118 cases (21%) were associated with contact lens wear; of these, 64 were culture-positive. Of these culture-positive cases, 50 (78%) were caused by gram-negative bacteria, nine (14%) by gram-positive organisms, and two (3%) by fungal organisms. Of the 264 culture-positive ulcers not associated with contact lens wear, 119 (45%) were caused by gram-negative bacteria, 74 (28%) by gram-positive organisms, and 63 (24%) by fungal organisms. These statistically significant differences suggested that the organisms associated with ulcerative keratitis within our geographic region are modified by contact lens use. Pseudomonas was the organism most frequently isolated from ulcers associated with contact lenses and was responsible for nearly two thirds of the culture-positive cases.

Contact Lenses↗
PubMed1986

Neodymium-YAG laser posterior capsulotomy. Central corneal endothelial cell density.

We determined central corneal endothelial cell densities in 39 eyes in a masked fashion before and after Q-switched neodymium-YAG laser posterior capsulotomy. The mean preoperative endothelial cell count was 1,840 cells per square millimeter (SD, 611 cells per square millimeter; range, 522 to 2,742 cells per square millimeter). The mean postoperative endothelial cell count was 1,798 cells per square millimeter (SD, 600 cells per square millimeter; range, 478 to 2,750 cells per square millimeter). The difference between the mean preoperative and postoperative cell density was 42 cells per square millimeter (2.3% cell loss). There was no significant correlation between central corneal endothelial cell loss and the laser energy used, pseudophakic status (posterior chamber intraocular lens vs no intraocular lens), size of capsulotomy, vitreocorneal touch, or preoperative corneal endothelial cell density.

Cataract Extraction↗
PubMed1986

Late development of ulcerative keratitis in radial keratotomy scars.

We describe three patients in whom ulcerative keratitis developed seven months to 2 1/2 years after uncomplicated radial keratotomy. All ulcers occurred along keratotomy scars within the interpalpebral fissure or inferiorly. At least one case developed spontaneously; another patient may have sustained an unrecognized corneal injury. The third patient was using an extended-wear soft contact lens for correction of residual myopia. Bacteria were isolated from two of the ulcers. With therapy, all ulcers healed without reducing visual acuity. We hypothesize that the altered structure of the slowly healing keratotomy incisions coupled with redistribution of the tear film due to changes in corneal topography may result in intermittent epithelial irregularities. Alone or in conjunction with any form of mechanical or hypoxic corneal injury, these changes along keratotomy incisions may predispose to corneal infection.

Adult↗
PubMed1986

Pseudophakic endophthalmitis. Diagnosis and management.

Eighty-three cases of endophthalmitis occurring in eyes with intraocular lenses are presented. A problem with the cataract section was felt to contribute to development of the endophthalmitis in 22% of patients. Seventy-five percent of eyes were culture positive with a microbiologic spectrum similar to other reported series without lens implants. Staphylococcus epidermidis was the most common organism accounting for 38% of the isolates. Therapeutic vitrectomy was performed in 46 cases (55%), generally in those eyes with the most severe inflammation. Intraocular lenses were removed in 23 cases (28%), usually to facilitate vitrectomy. Only 1 of 57 eyes with bacterial endophthalmitis could not be sterilized while the intraocular lens was retained. Visual acuity of 20/400 or better was achieved in 63% of culture positive cases, in 78% of eyes infected with S. epidermidis, and in 94% of culture negative eyes.

Aged↗