Louis A. Wilson

Spectrum and Susceptibilities of Microbiologic Isolates in the Endophthalmitis Vitrectomy Study

PURPOSE To determine the microbiologic spectrum and antibiotic susceptibilities of infecting organisms in postoperative endophthalmitis and to evaluate the effects of operative factors on the microbiologic spectrum. METHODS Patients with bacterial endophthalmitis presenting within six weeks of cataract extraction or secondary intraocular lens implantation (IOL) were evaluated. Cultures and Gram stains were performed on intraocular specimens and susceptibility tests on the isolates. RESULTS Confirmed microbiologic growth was demonstrated from intraocular specimens from 291 of 420 patients (69.3%). Gram-positive bacteria were isolated from 274 patients (94.2%) with confirmed growth and gram-negative bacteria from 19 (6.5%). Two hundred twenty-six of the 323 isolates obtained (70.0%) were gram-positive, coagulase-negative micrococci, 32 (9.9%) Staphylococcus aureus, 29 (9.0%) Streptococcus species, seven (2.2%) Enterococcus species, ten (3.1%) miscellaneous gram-positive species, and 19 (5.9%) gram-negative species. All gram-positive isolates tested were susceptible to vancomycin. Seventeen gram-negative isolates (89%) were susceptible to both amikacin and ceftazidime and two (11%) were resistant to both. Anterior chamber or secondary IOL implantations were associated with higher rates of infection with gram-positives other than coagulase-negative micrococci than were posterior chamber IOL implantations (P = .022) or primary cataract extractions (P = .024). CONCLUSIONS Gram-positive, coagulase-negative micrococci predominated in this series. Vancomycin was active against all gram-positive isolates tested. Amikacin and ceftazidime showed equivalent activity against gram-negative isolates. Secondary or anterior chamber lens implantations were associated with a possible spectrum shift toward gram-positive organisms other than the coagulase-negative micrococci.

Mortality rate in rheumatoid arthritis patients developing necrotizing scleritis or peripheral ulcerative keratitis. Effects of systemic immunosuppression.

We performed a nonrandomized clinical trial comparing the ocular and systemic efficacy of cytotoxic immunosuppression with steroidal and nonsteroidal anti-inflammatory therapy in the care of 34 patients with rheumatoid arthritis who developed peripheral ulcerative keratitis and/or necrotizing scleritis. Nine of the 17 patients managed with conventional therapy died of a vascular-related event during the ten-year period of the study. In 13 of the 17 patients, the ocular inflammatory process progressed, and in 5 patients extraocular, although nonlethal, vasculitic lesions developed. One of 17 patients treated with long-term immunosuppressive therapy died during the ten-year follow-up period, and this death occurred after cytotoxic therapy was withdrawn. None of the patients on immunosuppressive regimens developed extraocular vasculitis while taking the drug, and none had progression of the ocular destructive lesion. The results of this study emphasize that the eye is a sensitive indicator for potentially lethal occult systemic vasculitis in patients with rheumatoid arthritis who develop peripheral ulcerative keratitis or necrotizing scleritis. Our mortality data strongly suggest that the use of cytotoxic drugs may alter favorably the general as well as the ocular prognosis in these patients.

Results of the Prospective Evaluation of Radial Keratotomy (PERK) Study One Year After Surgery

The Prospective Evaluation of Radial Keratotomy (PERK) study is a nine-center, self-controlled clinical trial of a standardized technique of radial keratotomy in 435 patients who had physiologic myopia with a preoperative refraction between -2.00 and -8.00 diopters. The surgical technique consisted of eight incisions using a diamond micrometer knife with blade length determined by intraoperative ultrasonic pachymetry and the diameter of central clear zone determined by preoperative refraction. At one year after surgery, myopia was reduced in all eyes; 60% were within +/- 1.00 diopter of emmetropia; 30% were undercorrected and 10% were overcorrected by more than 1.00 diopter (range of refraction, -4.25 to +3.38 D). Uncorrected visual acuity was 20/40 or better in 78% of eyes. The operation was most effective in eyes with a refraction between -2.00 and -4.25 diopters. Thirteen percent of patients lost one or two Snellen lines of best corrected visual acuity. However, all but three eyes could be corrected to 20/20. Ten percent of patients increased astigmatism more than 1.00 diopter. Disabling glare was not detected with a clinical glare tester, but three patients reduced their driving at night because of glare. Between six months and one year, the refraction changed by greater than 0.50 diopters in 19% of eyes.

Immunosuppressive Therapy for Progressive Ocular Cicatncial Pemphigoid

In a controlled, nonrandomized, longitudinal cohort study, we studied the efficacy of systemic immunosuppression in treatment of progressive cicatricial pemphigoid affecting the eyes. Twenty-six patients were studied; 18 received systemic immunosuppressive drugs, and eight received conventional therapy. Three patients who received cytotoxic agents withdrew from the study with intolerable gastrointestinal distress. Fourteen of the 15 patients who were immunosuppressed successfully for prolonged periods experienced a cessation of their episodic ocular inflammation and a halting of their progressive conjunctival cicatrization. They maintained vision at least as good as that present when disease activity was brought under control; in two patients vision improved. The one patient who was adequately immunosuppressed and successfully maintained in such a state for two years but who had progressive ocular surface pathology with eventual blindness had concomitant rheumatoid arthritis and severe sicca syndrome. The three patients who withdrew from immunosuppressive therapy and the eight concomitant controls all showed continued episodic conjunctival inflammation and conjunctival cicatrization with development of severe keratopathy and profound visual loss. Complications in this series included alopecia (100%), anemia (78%), gastrointestinal distress (22%), hemorrhagic cystitis (11.1%), and severe leukopenia (5.5%). These results support the notion that abnormal immunoregulatory mechanisms are involved in the progressive disease activity in cicatricial pemphigoid and that systemic immunosuppression may have an appropriate role in the treatment of this disease.

Herpetic Eye Disease Study: A Controlled Trial of Oral Acyclovir for Herpes Simplex Stromal Keratitis

PURPOSE To evaluate the efficacy of oral acyclovir in treating stromal keratitis caused by herpes simplex virus (HSV) in patients receiving concomitant topical corticosteroids and trifluridine. METHODS The authors performed a randomized, double-masked, placebo-controlled, multicenter trial in 104 patients with HSV stromal keratitis without accompanying HSV epithelial keratitis. Sample size was chosen so that a 5%, one-tailed test would have an 80% chance of detecting a doubling of the median time to treatment failure. Patients were randomized to receive a 10-week course of either oral acyclovir (400 mg 5 times daily, n = 51) or placebo (n = 53). All patients also received a standard regimen of topical prednisolone phosphate and trifluridine. Ophthalmologic examinations were performed weekly during the 10-week treatment period, every 2 weeks for an additional 6 weeks, and at 6 months after entry into the trial. RESULTS The median time to treatment failure (defined as worsening or no improvement of stromal keratitis or an adverse event) was 84 days (95% confidence interval, 69-93 days) for the acyclovir group and 62 days (95% confidence interval, 57-90 days) for the placebo group. By 16 weeks, 38 patients (75%) in the acyclovir group and 39 patients (74%) in the placebo group had failed treatment. Also by that time, the keratitis had resolved with trial medications, and there was no subsequent worsening in nine patients (18%) in the acyclovir group and ten (19%) in the placebo group. None of these results were significantly different between the two groups. However, visual acuity improved over 6 months in significantly more patients in the acyclovir group than in the placebo group. CONCLUSION There was no statistically or clinically significant beneficial effect of oral acyclovir in treating HSV stromal keratitis in patients receiving concomitant topical corticosteroids and trifluridine with regard to time to treatment failure, proportion of patients who failed treatment, proportion of patients whose keratitis resolved, time to resolution, or 6-month best-corrected visual acuity. Visual acuity improved over 6 months in more patients in the acyclovir group than in the placebo group.

Acanthamoeba Keratitis: A Growing Problem in Soft and Hard Contact Lens Wearers

Eleven contact lens-wearing patients presented with Acanthamoeba keratitis. Eight cases were culture- and/or stain-positive for Acanthamoeba and three were presumed to have Acanthamoeba keratitis based on history and clinical findings. Six wore daily wear soft contact lenses, two wore extended-wear soft contact lenses, one wore a polymethylmethacrylate hard contact lens, one wore a gas-permeable hard contact lens, and one wore a Saturn lens (combined hard and soft lens). Four patients used distilled water and salt tablet saline, three used tap water and salt tablet saline, two used tap water rinse, two used well water rinse or storage, and one used intravenous (IV) saline. It is apparent that all contact lens wearers are at some risk for Acanthamoeba keratitis developing if proper contact lens care is not maintained. Of great concern is the inability of most current chemical sterilization methods to kill the organism if the lens becomes contaminated. Heat disinfection will kill Acanthamoeba trophozoites and cysts but the lens must not be placed into contaminated solutions afterward. Prevention is very important because medical and surgical treatment failures are frequent. Eye care practitioners who fit contact lenses are advised to use heat disinfection for low-water content stock soft contact lenses, and to use hydrogen peroxide without a catalyst for a minimum of 6 hours for all other stock lens fitting sets, to specifically inquire about contact lens care habits used by their patients, and to discourage the use of homemade saline solutions.

Penetrating Keratoplasty for Herpes Simplex Keratitis and Keratoconus: Allograft Rejection and Survival

To determine the relationship between corneal allograft rejection and failure, we studied patients who underwent penetrating keratoplasty for herpes simplex keratitis (n = 82) and keratoconus (n = 345), two frequent indications for keratoplasty in young patients, using survival analysis. For first grafts for herpes, the probability of survival was significantly less than it was for keratoconus (P less than 0.0001). For second grafts, this difference was less pronounced, and for three or more grafts, the difference in survival was not significant. The incidence of rejection episodes was similar in first grafts for herpes (16.6%) and keratoconus (18.5%) (P greater than 0.05). However, the incidence of rejection episodes in regrafts for herpes was significantly greater than in keratoconus (23.7 versus 17%, P less than 0.01). The incidence of failure after rejection episodes (first grafts and regrafts combined) was significantly greater in grafts for herpes (52.4 versus 16.2%, P less than 0.001). Because survival after multiple regrafts in both groups is poor, additional measures, such as tissue matching, may be necessary to improve the likelihood of success in these high-risk cases.

Bacterial and Fungal Endophthalmitis After Penetrating Keratoplasty

We analyzed 1,010 consecutive penetrating keratoplasties to determine the incidence of postoperative endophthalmitis, the frequency of positive donor rim cultures, and whether a correlation between these two factors exists. There were three cases of bacterial endophthalmitis, all caused by streptococci, and one case of Candida albicans endophthalmitis. In all cases except one case of streptococcal endophthalmitis, the same organism was cultured from the donor rim. We cultured 138 organisms from 128 of 932 donor rims (14%). A remarkable percentage of gram-positive organisms were resistant to gentamicin, the only antibiotic contained in corneal storage media. On the basis of our data and previously published data, we believe that donor material is frequently the source of microorganisms in endophthalmitis after penetrating keratoplasty.

Microbial contamination of contact lens storage cases and solutions

We compared microbial contamination of contact lens storage cases of asymptomatic contact lens wearers (Group 1; No. = 118; sampled once) and of contact lens wearers with manufacturers lens-care instructions reinforced (Group 2; No. = 62; sampled three, six, 12, and 20 weeks after initial advisement). A significantly higher incidence of contamination of contact lens storage cases and solutions was observed among samples from Group 1 (132 of 247 samples) as compared to samples from Group 2 (30 of 500 samples; P = .000). Contact lens storage cases of individuals in Group 2 who used hydrogen peroxide systems (four of 78) showed a significantly lower incidence of contamination as compared to individuals who used other chemical disinfection (11 of 62 soft lens users; 10 of 59 rigid gas-permeable lens users; P = .041). Biofilms, adhered microorganisms embedded in a glycocalyx, in contact lens storage cases were not always inactivated by the addition of fresh solutions. Cleaning and periodic replacement of contact lens storage cases is recommended.

Treatment of Microsporidial Keratoconjunctivitis with Topical Fumagillin

Encephalitozoon hellem is a newly described cause of microsporidial keratoconjunctivitis, occurring chiefly in patients with significantly diminished CD4+ T-lymphocyte levels. This disorder is symptomatically disabling and generally recalcitrant to topical antimicrobial therapy. Two homosexual men with E. hellem keratoconjunctivitis diagnosed by Gram stain, transmission electron microscopy, and specific indirect immunofluorescent assay were treated with topical fumagillin (Fumidil B). Both patients had marked symptomatic improvement with reduction of clinical findings. Symptoms and signs recurred with temporary discontinuation of the drug. Both patients, however, remained symptom-free on maintenance levels of topical fumagillin with no evidence of toxic side effects.