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Query: UMLS:C0022568 (keratitis)
 5,133 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The diagnosis of fungal keratitis can be difficult and is often delayed. The distinction between moniliaceous and dematiaceous (pigmented) keratomycoses is not commonly possible on clinical examination. We report a case of a Curvularia lunata fungal keratitis in a 40-year-old patient who presented with diffuse brown pigmentation throughout the ulcer bed. Histologic staining and growth on Sabourad's dextrose agar demonstrated the brown pigmentation characteristic of this pigmented fungus. We call attention to this clinical pigmentation as a helpful clue in the detection of dematiaceous fungal keratitis.
Cornea 1991 May
PMID:Macroscopic pigmentation in a dematiaceous fungal keratitis. 205 34

Extended wear soft contact lenses are associated with an increased incidence of Pseudomonas aeruginosa keratitis. Because the first step in the pathogenesis of this disease is adherence of the microorganism to the corneal surface, we studied the effect of soft contact lens wear on the adherence of P. aeruginosa to the cornea. Rabbits were fitted for extended wear soft contact lenses in the left eye, and the right eye served as a control. Both eyes were then closed with a partial tarsorrhaphy. After 1-5 days of wear, the lenses were removed and the corneas of the left and right eye were removed. Differences in the number of adherent Pseudomonas and in lectin binding to lens-wearing corneas and non-lens-wearing corneas were determined. After 1, 3, and 5 days of soft contact lens wear, there was a significant increase in the number of P. aeruginosa adherent to the lens-wearing cornea. Three to eight times as many bacteria adhered to the lens-wearing eye as compared with the control eye (p less than 0.05). In addition, a soft contact lens placed in the eye followed by the immediate application of P. aeruginosa resulted in an eightfold increase in adherence of bacteria to the lens-wearing cornea (p less than 0.05). Lens wear also led to an increase in binding of concanavalin A (Con A), wheat germ agglutinin (WGA), and Maclura pomifera agglutinin (MPA) to surface epithelium covered by the lens. These corneal epithelial changes induced by extended wear soft contact lenses may provide some insight as to why soft contact lens wearers are predisposed to Pseudomonas keratitis.
Cornea 1990 Jul
PMID:Contact lens wear enhances adherence of Pseudomonas aeruginosa and binding of lectins to the cornea. 211 22

Acanthamoeba may cause a severe keratitis in contact lens wearers. Since most sterilization techniques require rinsing the lenses prior to insertion, contaminated solutions represent a potential vector for transmission of Acanthamoeba. The ability of rinse solutions to sustain an inoculum of Acanthamoeba polyphaga was investigated. A. polyphaga was exposed to 0.1% benzalkonium chloride, 0.001% thimerosal/0.1% edetate disodium, 0.1% edetate disodium, saline, tap water, and distilled water. The status of the organism was evaluated with direct microscopic counts and cultures to confirm viability. Incubation with 0.1% edetate disodium, saline, tap water, and distilled water resulted in the maintenance of reduced populations of viable organisms for 7 days. Benzalkonium chloride preserved saline and solutions containing thimerosal with edetate rendered the Acanthamoeba nonviable.
Cornea 1990 Oct
PMID:Survival of Acanthamoeba in contact lens rinse solutions. 212 39

Microbial keratitis with Pseudomonas aeruginosa is the most common corneal infection associated with contact lenses (CLs). Pseudomonas organisms are ubiquitous in nature, and can colonize CLs without a prior breach in lens care or hygiene. Although poor lens care is often found in affected patients, lens contamination and traumatic epithelial defects are more relevant. Hydrophilic lenses, particularly extended wear lenses, have been associated with a greater frequency of Pseudomonas keratitis. The polymer matrix of these lenses is apparently suited to the avid adherence of Pseudomonas organisms. Adherence is promoted by the presence of lens coatings, which begin to accumulate upon lens insertion and whose level mounts over time. Evidence suggests that infection is more common with mucin-coated contaminated CLs than with noncoated contaminated CLs. In general, lens wear can promote bacterial adherence to the ocular surface by shielding the cornea from the wiping action of the eyelids and immune components in tears. Still, experimental models have shown that keratitis develops regularly (84%) only in corneas that have been traumatized. Trauma may arise through lens insertion or removal, deposits or debris entrapment, hypoxia, or toxic reactions to solution preservatives. Extended wear is believed to facilitate the infectious process because of the chronic accumulation of coatings, the chronic exposure of CLs to potentially adherent bacteria, the continuous presence of irritating lens deposits, the prolonged entrapment of debris beneath the lens, and the relative infrequency of lens cleaning and disinfection.
Cornea 1990
PMID:Pseudomonas keratitis and contact lens wear: the lens/eye is at fault. 218 78

The overriding consideration in choosing between soft contact lenses (SCLs) and rigid gas-permeable (RGP) lenses is the severity of the changes each induces in the corneal epithelium, endothelium, and conjunctival structures. Lens-related epithelial changes are largely the consequence of relative oxygen deprivation and consequent corneal edema. Factors such as lower oxygen transmissibility, minimal tear exchange capacity, and large diameters may explain why SCL wearers show a higher rate of corneal infiltrates, sterile ulcers, and irregular staining patterns than users of RGP lenses. The greater association of hydrogels with infectious keratitis may reflect their tendency to accumulate proteinaceous deposits, harbor bacteria in the polymer matrix, and resist easy disinfection. SCL wear has been linked to endothelial polymegethism, a largely irreversible condition that may cause more rapid corneal swelling and slower deswelling after periods of hypoxic stress. Among the conjunctival problems more often seen in SCL wearers are superficial neovascularization, contact lens-related superior limbic keratoconjunctivitis, and giant papillary conjunctivitis. Mechanical irritation from large-diameter lenses, a tendency to build up mucoproteinaceous deposits, corneal draping, and hypersensitivity to preservatives in SCL care products may play a role in these problems.
Cornea 1990
PMID:Are hard lenses superior to soft? Arguments in favor of hard lenses. 218 86

We reviewed the records of 22 patients whose corneal ulcers were associated with therapeutic soft contact lens wear. The patients required hospitalization on the Cornea Service at Wills Eye Hospital between January 1, 1978 and September 1, 1988. A majority of the ulcers were associated with pseudophakic or aphakic bullous keratopathy (9 of 22 cases; 41%); neurotrophic/exposure keratitis was the second most common diagnosis (7 of 22; 32%). Most patients used topical antibiotics (15 of 22; 68%) and/or corticosteroids (13 of 22; 59%). Cultures were positive in 15 of 22 cases (68%). Gram-positive organisms were isolated in 60% the culture-positive cases (9 of 15). Streptococcus was the most common organism isolated (6 of 15 culture positive-cases; 40%). Gram-negative organisms were found in four of 15 culture-positive ulcers (27%). There was only one Pseudomonas infection in the series. Uncommon organisms--including Candida, atypical mycobacteria, Achromobacter, Acinetobacter and Micrococcus--were isolated in five cases. Therapeutic soft contact lens wearers are at risk for developing corneal ulcers; most often these are caused by gram-positive bacteria, especially streptococci, and uncommon organisms.
 ...
PMID:Microbial keratitis and corneal ulceration associated with therapeutic soft contact lenses. 230 53

Two hundred thirty consecutive cases of presumed infectious keratitis were reviewed. Cultures were positive in 49.5% (114 of 230). Acridine orange stain sensitivity (81%) was significantly greater than gram stain sensitivity (65%) (p less than 0.002). Gram stain specificity was 92%, and acridine orange specificity was 89%. In keratitis with low or moderate growth, acridine orange was positive in 73% (61 of 84) as compared with Gram stain 53% (45 of 84), (p less than 0.001). In cases of heavy microbial growth, Gram stain was positive in 97% (29 of 30), acridine orange in 100% (30 of 30). This study demonstrates that both Gram stain and acridine orange stain are excellent in cases of infectious keratitis with heavy microbial growth, but that acridine orange is significantly better than Gram stain in cases with low amounts of organisms.
Cornea 1990 Apr
PMID:Acridine orange and Gram stains in infectious keratitis. 232 81

This paper reviews the data of Frank et al. in the light of increasing concern over the safety of contact lenses used for extended wear. Relative risks were calculated for four types of contact lenses (CLs): extended wear soft, daily wear soft, rigid gas-permeable (RGP), and polymethylmethacrylate (PMMA) lenses--worn by a group of patients who presented themselves for emergency ocular treatment. The cases comprised 329 CL wearers who were found to have lens related metabolic disorders, toxic or hypersensitivity reactions, cornea abrasions, microbial keratitis, or some other lens-induced problem. Controls comprised 64 CL wearers whose ocular problems were unrelated to lens use. It was found that extended wear soft lenses were nearly 7 times more likely to be associated with an ocular disorder than PMMA hard lenses, and approximately 3.4 times more likely than daily wear soft lenses. Furthermore, extended wear soft lenses were nearly 5 times more likely to be linked with microbial keratitis than daily wear soft lenses, and approximately 7.5 times more likely than RGP lenses. Metabolic disorders were also more common with extended wear lenses (relatively risk: 3.3) than with either RGP (1.8) or daily wear soft lenses (2.0) or PMMA lenses (1.0). If the association between extended wear soft lenses and ocular complications is borne out in large population studies, eye-care professionals may need to reconsider the wisdom of prescribing these lenses for the cosmetic correction of vision.
Cornea 1990
PMID:A review of relative risks associated with four types of contact lenses. 234

Corneal neovascularization (CNV) can cause significant visual loss because of the scarring and lipid deposition that frequently accompany it. In addition, penetrating keratoplasty in a vascularized recipient carries a significant risk of failure from allograft rejection. Frequently CNV is induced by nonspecific inflammatory stimuli, mediated primarily by polymorphonuclear neutrophils. Neovascularization can also be associated with specific corneal immune reactions, such as herpes simplex keratitis. Immunologically mediated CNV may be more amenable to treatment than CNV that results from nonspecific inflammation. Photodynamic therapy (PDT) following the intravenous injection of hematoporphyrin derivative or purified dihematoporphyrin ether (DHE) has been shown to suppress tumor growth and blood vessel growth in the eye. We have developed a murine model of CNV induced by the intrastromal injection of stimulated lymphocytes or interleukin-2 (IL-2). We have noted corneal DHE retention following its intravenous injection in mice with IL-2 induced CNV. Preliminary studies indicate that PDT can induce regression of CNV in these mice. Other recent studies that have enhanced our understanding of the pathogenesis and treatment of CNV are reviewed, and directions for future research are discussed.
Cornea 1987
PMID:Corneal neovascularization. Pathogenesis and inhibition. 244 23

We studied the effect of minimal antibiotic therapy on pseudomonas keratitis in rabbits. Both corneas of 12 rabbits were infected with Pseudomonas aeruginosa and treated 24 and 48 h later with two drops of tobramycin or placebo. Corneal infections in antibiotic- and placebo-treated groups were comparable in appearance 24 and 48 h after inoculation. However, bacterial recovery was significantly less in eyes treated with minimal antibiotic therapy (p = 0.009). Although negative cultures were obtained from 11 of 12 antibiotic-treated eyes, bacteria could be recovered from eight of these culture negative corneas when corneas were ground and cultured. These studies suggest that minimal antibiotic therapy may impair bacterial recovery without completely eradicating live organisms.
Cornea 1989 Sep
PMID:Effect of minimal antibiotic treatment on bacterial keratitis. 250 Oct 67


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