The Antioxidants in Prevention of Cataracts Study: effects of antioxidant supplements on cataract progression in South India.

AIM: To determine if antioxidant supplements (beta carotene and vitamins C and E) can decrease the progression of cataract in rural South India. METHODS: The Antioxidants in Prevention of Cataracts (APC) Study was a 5 year, randomised, triple masked, placebo controlled, field based clinical trial to assess the ability of interventional antioxidant supplements to slow cataract progression. The primary outcome variable was change in nuclear opalescence over time. Secondary outcome variables were cortical and posterior subcapsular opacities and nuclear colour changes; best corrected visual acuity change; myopic shift; and failure of treatment. Annual examinations were performed for each subject by three examiners, in a masked fashion. Multivariate modelling using a general estimating equation was used for analysis of results, correcting for multiple measurements over time. RESULTS: Initial enrolment was 798 subjects. Treatment groups were comparable at baseline. There was high compliance with follow up and study medications. There was progression in cataracts. There was no significant difference between placebo and active treatment groups for either the primary or secondary outcome variables. CONCLUSION: Antioxidant supplementation with beta carotene, vitamins C and E did not affect cataract progression in a population with a high prevalence of cataract whose diet is generally deficient in antioxidants.

A novel arginine substitution mutation in 1A domain and a novel 27 bp insertion mutation in 2B domain of keratin 12 gene associated with Meesmann's corneal dystrophy.

AIM: To determine the disease causing gene defects in two patients with Meesmann's corneal dystrophy. METHODS: Mutational analysis of domains 1A and 2B of the keratin 3 (K3) and keratin 12 (K12) genes from two patients with Meesmann's corneal dystrophy was performed by polymerase chain reaction amplification and direct sequencing. RESULTS: Novel mutations of the K12 gene were identified in both patients. In one patient a heterozygous point mutation (429A-->C = Arg135Ser) was found in the 1A domain of the K12 gene. This mutation was confirmed by restriction digestion. In the second patient a heterozygous 27 bp duplication was found inserted in the 2B domain at nucleotide position 1222 (1222ins27) of the K12 gene. This mutation was confirmed by gel electrophoresis. The mutations were not present in unaffected controls. CONCLUSION: Novel K12 mutations were linked to Meesmann's corneal dystrophy in two different patients. A missense mutation replacing a highly conserved arginine residue in the beginning of the helix initiation motif was found in one patient, and an insertion mutation, consisting of a duplication of 27 nucleotides, was found before the helix termination motif in the other.

Ocular and sinus microsporidial infection cured with systemic albendazole.

PURPOSE: To report treatment of a patient with acquired immunodeficiency syndrome (AIDS) and ocular and paranasal sinus microsporidial infection. METHOD: Case report. RESULTS: A patient with AIDS and ocular microsporidial infection experienced resolution of ocular symptoms with topical fumagillin, but symptoms recurred upon cessation of therapy. Paranasal sinus microsporidial infection was diagnosed. The patient received sequential systemic treatment with itraconazole followed by albendazole. Sinus symptoms resolved with albendazole. He remained symptom-free with a normal examination 17 months after concluding therapy. CONCLUSIONS: Although fumagillin and itraconazole may have played a role, systemic albendazole appears to be responsible for clinical resolution of microsporidial infection.

Ocular flora of patients with AIDS compared with those of HIV-negative patients.

PURPOSE: To determine whether there are quantitative or qualitative differences in the ocular flora of patients with acquired immunodeficiency syndrome (AIDS) compared with human immunodeficiency virus (HIV)-negative patients. METHODS: Forty patients with AIDS and 42 HIV-negative controls were sex and age matched. All subjects had a detailed anterior segment examination, including Schirmer's test, rose bengal staining, and quantitative cultures of the conjunctiva and lids. Statistical evaluation of the relation between AIDS, keratoconjunctivitis sicca (KCS), and ocular flora was performed. RESULTS: No differences were observed in the types or numbers of organisms isolated from the conjunctiva or lids of patients with AIDS and HIV-negative subjects. Ocular flora was not influenced by use of systemic antibiotics, level of immunosuppression as measured by CD4 lymphocyte counts, KCS, or other ocular-surface disease. One AIDS patient was colonized by large numbers of Haemophilus influenzae OU with minimal clinical signs of inflammation or infection. CONCLUSION: There do not appear to be any differences in the ocular flora of HIV-negative patients and patients with AIDS. Presence of KCS and level of immunosuppression do not appear to affect the ocular flora in patients with AIDS.

Antibiotic supplementation of intraocular irrigating solutions. An in vitro model of antibacterial action.

PURPOSE: The addition of antibiotics to infusion solutions for cataract surgery is becoming increasingly popular. The authors developed an in vitro model to evaluate antibacterial effects of this use of antibiotics. METHODS: Clinical isolates and/or reference strains of the following organisms were examined: coagulase-negative Staphylococcus spp, Staphylococcus aureus, Streptococcus pneumoniae, Streptococcus viridans, Streptococcus spp, Enterococcus spp, Proprionibacterium acnes, Moraxella nonliquifaciens, and Pseudomonas aeruginosa. Standardized suspensions of each organism were incubated with a control solution (Balanced Salt Solution) or Balanced Salt Solution containing the following antibiotics: vancomycin (20 micrograms/ml) or gentamicin (8 micrograms/ml) or gentamicin and vancomycin combined (8 and 20 micrograms/ml, respectively). Suspensions were incubated for 30, 60, and 120 minutes at room temperature. Samples were centrifuged, and the organisms were washed with Balanced Salt Solution before quantitative culturing. Each organism also was incubated for 48 hours in Mueller-Hinton broth with the same antibiotic concentrations. RESULTS: Most of the organisms were not affected by exposure to the antibiotics for up to 140 minutes. P. aeruginosa and M. nonliquifaciens were exceptions, decreasing in colony numbers even with 30 minutes of exposure. Several Staphylococcus spp yielded variable results. All organisms demonstrated nearly complete inhibition of growth when exposed for an extended time to the appropriate antibiotic in broth. CONCLUSIONS: Exposure to antibiotics for a short period of time, such as during intraocular surgery, generally has no effect on organisms commonly responsible for endophthalmitis. The use of antibiotics in this manner should be critically reassessed until further study.

Ultrastructural localization of hydrogen peroxide in experimental autoimmune uveitis.

One of the most prominent features of S-antigen induced uveitis is the massive infiltration of polymorphonuclear leukocytes (PMNs) and mononuclear cells in the ocular tissues and fluids. These inflammatory cells generate reactive oxygen metabolites as microbicidal agents and release these oxidants into the surrounding tissues. Using the cerium perhydroxide method, we have localized subcellular hydrogen peroxide in various inflamed ocular tissues. Most notably, the positive electron-dense granules were seen in the plasma membranes of PMNs that were infiltrating in the retina and uvea. These deposits were noted also in PMNs located within the extravascular spaces. For the intravascular PMNs, the positive reaction products were seen in much lower concentrations. A direct demonstration of substantial concentrations of hydrogen peroxide in experimental autoimmune uveitis, therefore, suggests the possibility that this reactive metabolite is an inflammatory mediator in this condition.

Anti-inflammatory therapy and outcome in a guinea pig model of Pseudomonas keratitis.

Corneal scarring as a consequence of bacterial keratitis is an important cause of visual loss and a major indication for penetrating keratoplasty. Anti-inflammatory agents might be useful in this condition for limiting corneal damage, but benefit from adjunctive anti-inflammatory therapy has never been demonstrated. In this limited pilot study, we compared the effect on clinical outcome of treating Pseudomonas keratitis in guinea pigs with prednisolone (a corticosteroid), flurbiprofen (a cyclo-oxygenase inhibitor), nordihydroguaiaretic acid (a lipoxygenase inhibitor), and a leukotriene antagonist, SKF104353 [R-(R*, S*)]-beta-[(2-carboxyethyl) thio-alpha-hydroxy-2-(8-phenyloctyl) benzenepropanoic acid, zinc salt]. None of the anti-inflammatory agents prevented sterilization of ulcers with antibiotic (ofloxacin) therapy. Therapy with the leukotriene antagonist appeared to reduce infiltrate size more quickly and produce a more rapid reduction in lesion size, but the differences were not statistically significant. Sample size calculations suggest that very large numbers of animals would be required to prove efficacy. The role of anti-inflammatory agents in reducing the stromal destruction caused by bacterial keratitis remains controversial.

Recurrence of microbial keratitis concomitant with antiinflammatory treatment in an animal model.

Recurrence of Pseudomonas keratitis during treatment with corticosteroids has been reported previously in humans. Rabbits with keratitis due to Pseudomonas aeruginosa or Streptococcus pneumoniae were treated with antibiotics and either vehicle, methylprednisolone acetate, flurbiprofen, or nordihydroguaiaretic acid (NDGA). Cultures performed after 7 days were negative, and antibiotics were discontinued. Two weeks later, Pseudomonas keratitis recurred in 6 of 7 (85.7%) steroid-treated rabbits, 1 of 8 (12.5%) flurbiprofen-treated rabbits, 1 of 8 (12.5%) NDGA-treated rabbits, and none of 8 vehicle-treated rabbits. None of the 31 rabbits infected with Streptococcus pneumoniae experienced recurrence. These data confirm the clinical observation that Pseudomonas keratitis may recur if antibiotic therapy is discontinued and corticosteroids are administered; the risk of recurrence appears to be much less with nonsteroidal antiinflammatory agents.

Infectious crystalline keratopathy with ring opacity.

A 41-year-old physician was treated for 3 months with antiviral medications, antibiotics, and steroids for presumed herpetic keratitis. When seen by us, an annular infiltrate was observed, along with crystalline-like opacities in the superficial one third of the stroma. Cultures of scrapings and of subsequent biopsies were positive for Streptococcus mitis of the viridans group; histopathology demonstrated large aggregates of cocci between the stroma lamellae. Tapering of topical corticosteroids and treatment with topical penicillin resulted in resolution of the infiltrates. The clinical appearance and findings in this patient suggest that infectious crystalline keratitis can produce an annular infiltrate. Injection of the organism into rabbit corneas produced a crystalline infiltrate, but no annular opacity was observed. Corticosteroids altered the clinical and histopathologic appearance of the lesions in rabbits.

Topical ofloxacin in the treatment of Pseudomonas keratitis in a rabbit model.

Ofloxacin, a new quinolone antibiotic with a broad spectrum of activity, is very effective against Pseudomonas aeruginosa in vitro. Its effectiveness was studied in a rabbit model of tobramycin-sensitive P. aeruginosa. Treatment groups received either vehicle, tobramycin 0.3%, or ofloxacin 0.3%. Twelve hours of treatment decreased the bacterial counts from a mean of 2.2 +/- 0.7 x 10(6) colony forming units (cfu) per cornea in the vehicle group to means of 513 +/- 670 and 435 +/- 524 cfu in the tobramycin and ofloxacin groups, respectively. This decrease in bacterial counts was statistically significant (p = 0.001 for tobramycin and ofloxacin each compared with control, p = 0.86 for tobramycin compared with ofloxacin). After seven days, all antibiotic-treated corneas were sterile and the epithelial defects healed at comparable rates. Aqueous humor drug levels were higher in infected eyes without an intact epithelium (p = 0.02); in eyes with intact epithelium, concentrations of ofloxacin were higher than were those of tobramycin (p = 0.002). In this animal model, ofloxacin proved to be an effective antibiotic with no evidence of toxicity.

Diurnal variation of corneal topography after radial keratotomy.

A computerized videokeratography system was used to evaluate diurnal changes in corneal curvature of both untreated and surgically treated eyes of 11 patients who had undergone unilateral radial keratotomy. The mean postoperative interval was 34.5 months. Both corneas operated on and those not operated on steepened on average from morning to evening. For untreated eyes, this diurnal steepening was statistically significant at a distance of 0.5 mm from the corneal apex (mean +/- SE, 0.36 +/- 0.07 diopter) and in the inferotemporal quadrant (0.28 +/- 0.08 D); in eyes that had undergone radial keratotomy, steepening was significant at from 1.0 to 3.0 mm from the corneal apex (0.39 +/- 0.07 D) and temporal, inferotemporal, inferior, inferonasal, nasal, and superonasal to the corneal apex (0.42 +/- 0.08 D). The greatest steepening in the eyes treated with radial keratotomy compared with the untreated eyes occurred at 1.5 to 2.5 mm peripheral to the corneal apex in the inferonasal and nasal octants. Diurnal changes in intraocular pressure, corneal thickness, number of incisions, clear-zone size, postoperative period, and patient sex were not predictive of the magnitude of morning-to-evening change. Furthermore, diurnal changes in corneal curvature of untreated eyes were not predictive of diurnal changes in the fellow eyes after radial keratotomy.

Chemotactic activity of the peroxidized retinal membrane lipids in experimental autoimmune uveitis.

We investigated the mechanism for amplification of intraocular inflammation in rats with experimental autoimmune uveitis by examining the chemotaxis potentials of peroxidized lipids extracted from the retinas. Utilizing thin layer chromatography, we found that the peroxidized products isolated from the inflamed retinas were fatty acid hydroperoxides that corresponded to the autooxidized products from commercial methyl docosahexaenoate, with Rf values ranging from 0.30 to 0.37. These were not demonstrated in similar preparations from normal retinas or in unoxidized docosahexaenoate. Boyden chamber assay revealed that the hydroperoxides isolated from inflamed eyes and the products of oxidized methyl docosahexaenoate possessed significantly higher chemotactic activity than did the retinal lipids isolated from normal eyes (P less than 0.01). These findings may help to explain the mechanism of inflammatory amplification induced by peroxidized retinal lipids that is seen in this animal model of uveitis.

Histochemical localization of superoxide production in experimental autoimmune uveitis.

Although the presence and role of oxygen reactive species in uveal inflammation is the subject of intense investigation, there is little direct evidence that oxygen metabolites are present at the site of inflammation. We used the nitroblue tetrazolium test for superoxide to determine production of this oxygen reactive species in experimental autoimmune uveitis (EAU). The choroidal tissues of animals with this disease contained intracellular, blue-staining granules. Most of the positive staining cells appeared to be polymorphonuclear leukocytes. This localization of superoxide in EAU is further evidence of the generation of oxygen reactive species in uveal inflammation.

Fluorescence of blood-stained cornea.

Corneal blood staining represents deposition of hemoglobin and its breakdown products within the cornea. Pathologic examination of these corneas typically reveals degenerating endothelial cells and keratocytes. These degenerative changes have typically been attributed to the blunt trauma itself or to toxicity of the erythrocytic debris (a "localized hemosiderosis"). Another possible mechanism for this injury, however, is porphyrin-induced photosensitivity. Examination of frozen sections of an acutely blood-stained human cornea demonstrated fluorescence within all layers of the cornea, similar to that seen with hematoporphyrin derivative. The production of cytotoxic oxygen species within the blood-stained cornea exposed to light may contribute to endothelial and keratocyte degeneration. Limiting light exposure of blood-stained corneas or eyes with hyphemas might theoretically reduce light-induced and porphyrin-mediated toxicity.