Association between moxifloxacin ophthalmic solution and fungal infection in patients with corneal ulcers and microbial keratitis.

BACKGROUND: Fungal keratitis is a painful and dangerous fungal infection of the cornea. Recently, use of a contact lens solution with a novel ophthalmic preservative was linked to an increased risk of fungal keratitis. This study investigated whether fungal contamination was present in bottles of a widely used moxifloxacin ophthalmic solution, and whether there was an association between the use of this solution and fungal keratitis in a corneal referral practice. METHODS: Fungal cultures were obtained for 32 moxifloxacin bottles brought in by 32 keratitis patients referred to our cornea practice from June 2003 to March 2006. Demographic and clinical data were also collected for 29 patients with fungal keratitis and 82 patients with bacterial keratitis, referred to our practice for corneal ulcers between June 2003 and April 2006. These two groups were compared with respect to moxifloxacin use and other variables. Logistic regression was carried out to determine whether an association between fungal keratitis and moxifloxacin use was present after taking into account potential confounding variables. RESULTS: Thirteen (41%) of the bottles of moxifloxacin solution grew fungus on culture. Patients with fungal keratitis were nearly twice as likely as patients with bacterial keratitis to report the use of moxifloxacin ophthalmic solution: 41% vs. 22% (P = 0.043). The association between fungal keratitis and moxifloxacin use persisted after taking into account potential confounding variables. CONCLUSIONS: Fungal contamination is present in the moxifloxacin bottles used by some keratitis patients. There appears to be an association between the use of moxifloxacin ophthalmic solution and fungal keratitis.

Variable responses of Acanthamoeba strains to three multipurpose lens cleaning solutions.

PURPOSE: A novel method has been developed to compare Acanthamoeba strain differences by testing their susceptibility to multipurpose contact lens cleaning solutions (MPS). METHODS: This method uses surface-attached amoebae that mimic cells attached to a contact lens. In brief, acanthamoebae were grown on non-nutrient agar plates with Escherichia coli prey. Blocks of agar with cysts or trophozoites (approximately 50 cells) were cut out and transferred to MPS [ReNu MultiPlus; (Bausch & Lomb, Rochester, NY), Complete (Allergan, Irvine, CA), and Opti-Free Express (Alcon, Ft. Worth, TX)] for up to 24 h treatment. After neutralizing in Dey Engley broth (Difco), blocks were washed in amoeba saline and reinoculated onto fresh prey bacteria. Positive growth was indicative of survival. RESULTS: Testing showed that the efficacy of the three MPS was different. Opti-Free was the most effective against cysts, followed by ReNu while Complete was relatively ineffective. Not surprisingly, trophozoites were more susceptible than cysts. CONCLUSIONS: Findings for individual MPS complement previous work with other methods. This study has also identified that environmental strains vary in their sensitivity to disinfecting solutions. Overall, Acanthamoeba genotypes T3, T5, and T11 from the environment were more resistant than the T4 isolates from the cornea and beach. This resilience supports previous work on temperature tolerance, in which T3 and T5, and T11 acanthamoebae grew in temperatures up to 41 degrees C. Investigators should therefore consider the strain genotype and its source before embarking on MPS sensitivity testing.

Myopic progression and dark focus variation in optometric students during the first academic year.

BACKGROUND: The aim of this research was to investigate the change in refractive error (RE) of optometric students during their first academic year and whether these changes relate to changes in their dark focus (DF). METHOD: The RE and DF of 64 students were measured objectively every three months during the first academic year, a total of four times, using a Canon R-1 infrared optometer. Thirty-five of the 64 students had an additional RE and DF measurement three weeks immediately after their Summer vacation. Students completed a survey regarding the near work demands they experienced during the Winter break and the teaching semesters. RESULTS: Over nine months, the average RE of the students changed significantly from -2.22 +/- 1.93 (SD) D to -2.50 +/- 2.05 D (p = 0.0002). The rate of myopic progression averaged -0.37 dioptres per year. Inclusion of measurements taken on 35 students immediately after the Summer vacation showed that their change in RE during the Summer vacation was not significant (p = 0.79). For these subjects, the DF measured immediately after the vacation was significantly lower than the DF measured before the vacation (p = 0.007). The reduction in the DF after the vacations corresponded to a period of relative myopic stability in these subjects. CONCLUSIONS: The results of this study suggest that optometric students performing extensive near work are at risk of developing myopia. The variation of their DF values indicates the changing demand for near work during different periods of the year. After Winter and Summer vacations, the DF was lower and the myopic progression was suspended. These findings further support the notion that myopic progression is related to high near work demands and suggest that this progression can be slowed by a period of reduced near work, for example, vacation periods.

Choroiditis, pigment epithelial detachment, and cystoid macular edema as complications of poststreptococcal syndrome.

PURPOSE: Two cases of poststreptococcal uveitis are presented. One patient developed nongranulomatous anterior uveitis (case 1). A second patient developed nongranulomatous anterior uveitis followed by granulomatous uveitis with concurrent choroiditis, retinal pigment epithelial detachment, and cystoid macular edema (case 2). Current concepts regarding the pathogenesis of poststreptococcal syndrome and its ocular sequelae are also discussed. CASE REPORTS: Case 1: A 31-year-old female patient presented with bilateral nongranulomatous uveitis after a recent onset of sore throat. A past diagnosis of rheumatic fever was revealed during acquisition of the patient's history. Blood chemistry analysis indicated elevated anti-streptolysin O antibody titers as the only significant elevated result. Case 2: A 33-year-old female presented initially with bilateral nongranulomatous uveitis. A history of recurrent sore throat was reported. Blood chemistry analysis revealed elevated anti-streptolysin O antibody titers only. "Mutton fat" keratic precipitates eventually developed; however, the bilateral uveitis resolved after topical cycloplegic and corticosteroid treatment. An anterior granulomatous uveitis with concurrent choroiditis, retinal pigment epithelial detachment, and cystoid macular edema ensued during a recurrent episode. Blood chemistry analysis was unremarkable at that time. CONCLUSIONS: : Anterior nongranulomatous/granulomatous and posterior uveitis should be considered clinical manifestations of poststreptococcal syndrome in patients with a clinical history and/or serological evidence indicating possible past streptococcal infection. A variation of host-genetic-predisposed immune response, the patient's human leukocyte antigen haplotype, pathogen virulence, and/or deposition location of immune circulating complexes may give rise to the diverse spectrum of clinical ocular sequelae in poststreptococcal syndrome. Poststreptococcal uveitis may comprise a similar immunologic pathogenesis to that of acute rheumatic fever, acute glomerulonephritis, and other autoimmune diseases.

Ophthalmomyiasis caused by the sheep bot fly Oestrus ovis in northern Iraq.

Myiasis is the feeding of fly larvae on vertebrates. The sheep bot fly larva of Oestrus ovis is a mammalian parasite of the skin, nose, ears, and eyes. When the larvae infest and feed on the structures of the eye, the condition is termed ophthalmomyiasis. Most often this infestation is limited to the external structures of the eye and is referred to as ophthalmomyiasis externa. The features of this condition are severe local inflammation, positive foreign body sensation, erythema, and lacrimation. Vision may or may not be reduced, depending on involvement of the cornea. A 20-year-old white male soldier sought treatment for an inflamed eye and an irritated cornea OS. His eyelids were swollen with marked periorbital edema and conjunctival erythema OS. On slitlamp examination, small whitish organisms were viewed on the conjunctiva OS. The organisms were removed, preserved, and sent to Nova Southeastern University where they were identified as O. ovis first-stage larvae. The patient was treated with antibiotic ointment, and the inflammation resolved within 1 week. O. ovis has a worldwide distribution, and although sheep are the preferred host, humans may also serve as an intermediate host in the organism's life cycle. This case represents one of several reports of ophthalmomyiasis in the Middle East caused by O. ovis. U.S. troops stationed in Iraq and surrounding areas are vulnerable to eye infestation by fly larvae, and health care providers need to include this condition in their differential diagnosis of anterior segment inflammatory disorders.

Vitreal pathogenic role in optic pit foveolar retinoschisis and central serous retinopathy.

PURPOSE: To expand on current theories concerning the vitreal-induced mechanism underlying the development of foveolar retinoschisis and macular sensory detachments associated with optic nerve head pits. To propose the notion that vitreal traction may contribute to the pathogenesis of serous detachments in central serous chorioretinopathy (CSC). REPORTS: We describe two patients, one with macular retinoschisis and the other with central serous detachment. The first patient, a 45-year-old Hispanic female, presented with a temporally located optic nerve head pit, foveolar retinoschisis and schisis retinal spaces extending to the surrounding macula and to the disc. The second patient, a 43-year-old Haitian male, developed a central serous retinal detachment OS with decreased visual acuity one day following in-office administration of Apraclonidine (0.5 per cent Iopidine, Alcon) and Dorzolamide-Timolol Maleate (Cosopt, Merck) to lower elevated intraocular pressure (IOP). Macular retinal pigment mottling and epiretinal membrane sheen OU had been observed on his initial visit. Visual acuity improved within a three-day period with resolution of the serous detachment. CONCLUSION: We suggest that the persistence of Cloquet's canal may permit fluid leakage into the proximal vitreous in cases of congenital optic nerve head pits. Tangential vitreal traction may promote the opening of a fistula at the optic pit and additionally thrust vitreal fluid into the pit and retinal space inducing the formation of schisis spaces, foveolar-schisis and underlying sensory serous detachment. We question whether a reduction in vitreous volume, induced by initial administration of anti-glaucoma medications, may contribute to the development and/or recurrence of central serous choroidopathy in predisposed individuals.