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Acanthamoeba Keratitis

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J Y Niederkorn – One of the best experts on this subject based on the ideXlab platform.

  • The immunobiology of Acanthamoeba Keratitis
    Microbes and infection, 2006
    Co-Authors: Daniel W. Clarke, J Y Niederkorn
    Abstract:

    Acanthamoeba spp. are free-living amoebae that cause Acanthamoeba Keratitis, a blinding corneal infection. The innate immune apparatus is crucial for the resolution of the disease. With the exception of mucosal antibody, elements of the adaptive immune system fail to prevent infection or contribute to its resolution in experimental animals.

  • Role of tear anti-Acanthamoeba IgA in Acanthamoeba Keratitis.
    Advances in experimental medicine and biology, 2002
    Co-Authors: J Y Niederkorn, H Alizadeh, Harrison D Cavanagh, Henry Leher, Sherine Apte, S. El Agha, L. Ling, Michael Hurt, Kevin Howard, J P Mcculley
    Abstract:

    Acanthamoeba Keratitis is a sight-threatening corneal disease caused by pathogenic free-living amoebae.1The organisms have been isolated from a wide variety of environments and from nasopharyngeal washes of asymptomatic individuals. 1Contact lens wear, practiced by over 25 million individuals in the United States, is the leading risk factor. Over 85% of the cases of Acanthamoeba Keratitis occurred in contact lens wearers.2 Antibodies against Acanthamoeba spp. were detected in 52-100% of normal subjects tested in two serological surveys.3,4 In spite of the ubiquity of Acanthamoeba spp., the large number of contact lens wearers, and the apparent frequency of exposure to Acanthamoeba antigens, Acanthamoeba Keratitis is rare. We hypothesized that frequent environmental exposure to Acanthamoeba antigens induces an immunity that protects against corneal infection in most contact lens wearers.

  • The diagnosis and management of Acanthamoeba Keratitis.
    The CLAO journal : official publication of the Contact Lens Association of Ophthalmologists Inc, 2000
    Co-Authors: J P Mcculley, H Alizadeh, J Y Niederkorn
    Abstract:

    Purpose: The purpose of this study was to evaluate the immunology, pathogenesis and therapy of Acanthamoeba Keratitis. Methods: The recent development of an animal model of Acanthamoeba Keratitis and its impact on the medical treatment and immunology of Acanthamoeba Keratitis was reviewed. Results: After initial reports, Acanthamoeba infection of the cornea remained a rare disease until an association with contact lens wear was first recognized. Although the disease is closely associated with contact lens wear, it appeared that the contaminated solutions that were coming into contact with the lenses caused the disease. All types of contact lenses can be associated with development of Acanthamoeba Keratitis. Therefore, the contact lens serves as a carrier of Acanthamoeba to the surface of the eye. The typical patient with Acanthamoeba Keratitis is a young healthy individual who is either a contact lens wearer or has had significant exposure to water contaminated with Acanthamoeba. There are several risk factors such as corneal trauma, contaminated solution and contact lenses that have been reported to be associated with Acanthamoeba Keratitis. In spite of significant improvement in the diagnosis of Acanthamoeba Keratitis, progress in developing and utilizing effective antimicrobial agents for treating this disease have been disappointing. A growing body of evidence suggests that the mammalian immune system, if properly activated, is capable of preventing and controlling ocular infections. Conclusions: In order to develop effective immunotherapeutic modalities, and to better understand the immune effector mechanisms that protect the cornea against Acanthamoeba infection, it is necessary to fully characterize and evaluate the immunobiology of Acanthamoeba Keratitis.

J P Mcculley – One of the best experts on this subject based on the ideXlab platform.

  • Updates in Acanthamoeba Keratitis
    Eye & contact lens, 2007
    Co-Authors: Shady T. Awwad, J P Mcculley, Walter M Petroll, Harrison D Cavanagh
    Abstract:

    Acanthamoeba Keratitis is a potentially blinding microbial disease that has been increasing in incidence during the past two decades. Prognosis of this serious disease had been dismal, but improvement in diagnosis, a better understanding of the natural course of the disease, and recent introduction of multiple and effective therapeutic agents have resulted in improvement of visual outcomes. A review of literature pertaining to Acanthamoeba Keratitis. Contact lens wear and exposure to contaminated water sources remain the most important risk factors; however, in vivo confocal microscopy and improved biomicroscopic screening have proven instrumental in accurate early diagnosis. Complications of Acanthamoeba Keratitis include dacryoadenitis, corneal melting and scarring, severe secondary glaucoma, cataract, and chronic anterior segment inflammation that can rarely lead to reactive blinding retinal ischemia. Combination chemotherapeutic agents have been shown to be more effective than monotherapy, whereas rehabilitative surgery such as penetrating keratoplasty is best performed on a quiet eye free of ocular inflammation and with no residual amoebae. Increased suspicion by clinicians for Acanthamoeba and confocal microscopy have allowed more rapid and accurate diagnosis; treatment with multiple antiamoeba drugs is essential to disease resolution. Provided there are no residual amoebae after treatment, penetrating keratoplasty has been successful in visual rehabilitation. Secondary glaucoma occurs frequently and may require drainage procedures for control of intraocular pressure. Posterior complications are rare but may lead to ischemic retinitis.

  • updates in Acanthamoeba Keratitis
    Eye & Contact Lens-science and Clinical Practice, 2007
    Co-Authors: J P Mcculley, Shady T. Awwad, Walter M Petroll, Harrison D Cavanagh
    Abstract:

    Purpose. Acanthamoeba Keratitis is a potentially blinding microbial disease that has been increasing in incidence during the past two decades. Prognosis of this serious disease had been dismal, but improvement in diagnosis, a better understanding of the natural course of the disease, and recent introduction of multiple and effective therapeutic agents have resulted in improvement of visual outcomes. Methods. A review of literature pertaining to Acanthamoeba Keratitis. Results. Contact lens wear and exposure to contaminated water sources remain the most important risk factors; however, in vivo confocal microscopy and improved biomicroscopic screening have proven instrumental in accurate early diagnosis. Complications of Acanthamoeba Keratitis include dacryoadenitis, corneal melting and scarring, severe secondary glaucoma, cataract, and chronic anterior segment inflammation that can rarely lead to reactive blinding retinal ischemia. Combination chemotherapeutic agents have been shown to be more effective than monotherapy, whereas rehabilitative surgery such as penetrating keratoplasty is best performed on a quiet eye free of ocular inflammation and with no residual amoebae. Conclusions. Increased suspicion by clinicians for Acanthamoeba and confocal microscopy have allowed more rapid and accurate diagnosis; treatment with multiple antiamoeba drugs is essential to disease resolution. Provided there are no residual amoebae after treatment, penetrating keratoplasty has been successful in visual rehabilitation. Secondary glaucoma occurs frequently and may require drainage procedures for control of intraocular pressure. Posterior complications are rare but may lead to ischemic retinitis.

  • Role of tear anti-Acanthamoeba IgA in Acanthamoeba Keratitis.
    Advances in experimental medicine and biology, 2002
    Co-Authors: J Y Niederkorn, H Alizadeh, Harrison D Cavanagh, Henry Leher, Sherine Apte, S. El Agha, L. Ling, Michael Hurt, Kevin Howard, J P Mcculley
    Abstract:

    Acanthamoeba Keratitis is a sight-threatening corneal disease caused by pathogenic free-living amoebae.1The organisms have been isolated from a wide variety of environments and from nasopharyngeal washes of asymptomatic individuals. 1Contact lens wear, practiced by over 25 million individuals in the United States, is the leading risk factor. Over 85% of the cases of Acanthamoeba Keratitis occurred in contact lens wearers.2 Antibodies against Acanthamoeba spp. were detected in 52-100% of normal subjects tested in two serological surveys.3,4 In spite of the ubiquity of Acanthamoeba spp., the large number of contact lens wearers, and the apparent frequency of exposure to Acanthamoeba antigens, Acanthamoeba Keratitis is rare. We hypothesized that frequent environmental exposure to Acanthamoeba antigens induces an immunity that protects against corneal infection in most contact lens wearers.

Harrison D Cavanagh – One of the best experts on this subject based on the ideXlab platform.

  • Updates in Acanthamoeba Keratitis
    Eye & contact lens, 2007
    Co-Authors: Shady T. Awwad, J P Mcculley, Walter M Petroll, Harrison D Cavanagh
    Abstract:

    Acanthamoeba Keratitis is a potentially blinding microbial disease that has been increasing in incidence during the past two decades. Prognosis of this serious disease had been dismal, but improvement in diagnosis, a better understanding of the natural course of the disease, and recent introduction of multiple and effective therapeutic agents have resulted in improvement of visual outcomes. A review of literature pertaining to Acanthamoeba Keratitis. Contact lens wear and exposure to contaminated water sources remain the most important risk factors; however, in vivo confocal microscopy and improved biomicroscopic screening have proven instrumental in accurate early diagnosis. Complications of Acanthamoeba Keratitis include dacryoadenitis, corneal melting and scarring, severe secondary glaucoma, cataract, and chronic anterior segment inflammation that can rarely lead to reactive blinding retinal ischemia. Combination chemotherapeutic agents have been shown to be more effective than monotherapy, whereas rehabilitative surgery such as penetrating keratoplasty is best performed on a quiet eye free of ocular inflammation and with no residual amoebae. Increased suspicion by clinicians for Acanthamoeba and confocal microscopy have allowed more rapid and accurate diagnosis; treatment with multiple antiamoeba drugs is essential to disease resolution. Provided there are no residual amoebae after treatment, penetrating keratoplasty has been successful in visual rehabilitation. Secondary glaucoma occurs frequently and may require drainage procedures for control of intraocular pressure. Posterior complications are rare but may lead to ischemic retinitis.

  • updates in Acanthamoeba Keratitis
    Eye & Contact Lens-science and Clinical Practice, 2007
    Co-Authors: J P Mcculley, Shady T. Awwad, Walter M Petroll, Harrison D Cavanagh
    Abstract:

    Purpose. Acanthamoeba Keratitis is a potentially blinding microbial disease that has been increasing in incidence during the past two decades. Prognosis of this serious disease had been dismal, but improvement in diagnosis, a better understanding of the natural course of the disease, and recent introduction of multiple and effective therapeutic agents have resulted in improvement of visual outcomes. Methods. A review of literature pertaining to Acanthamoeba Keratitis. Results. Contact lens wear and exposure to contaminated water sources remain the most important risk factors; however, in vivo confocal microscopy and improved biomicroscopic screening have proven instrumental in accurate early diagnosis. Complications of Acanthamoeba Keratitis include dacryoadenitis, corneal melting and scarring, severe secondary glaucoma, cataract, and chronic anterior segment inflammation that can rarely lead to reactive blinding retinal ischemia. Combination chemotherapeutic agents have been shown to be more effective than monotherapy, whereas rehabilitative surgery such as penetrating keratoplasty is best performed on a quiet eye free of ocular inflammation and with no residual amoebae. Conclusions. Increased suspicion by clinicians for Acanthamoeba and confocal microscopy have allowed more rapid and accurate diagnosis; treatment with multiple antiamoeba drugs is essential to disease resolution. Provided there are no residual amoebae after treatment, penetrating keratoplasty has been successful in visual rehabilitation. Secondary glaucoma occurs frequently and may require drainage procedures for control of intraocular pressure. Posterior complications are rare but may lead to ischemic retinitis.

  • Secondary glaucoma associated with advanced Acanthamoeba Keratitis.
    Eye & contact lens, 2006
    Co-Authors: Patrick S. Kelley, Adam P. Dossey, David Patel, Jess T. Whitson, Robert N Hogan, Harrison D Cavanagh
    Abstract:

    PURPOSE To describe the association of Acanthamoeba Keratitis and glaucoma, to establish an incidence of glaucoma in patients with Acanthamoeba Keratitis, to discuss treatment options and outcomes in these patients, and to describe the histopathologic findings and pathogenesis of glaucoma secondary to Acanthamoeba Keratitis. METHODS After Institutional Review Board approval, the charts of all patients suspected of having Acanthamoeba Keratitis at Aston Ambulatory Center at The University of Texas Southwestern Medical Center were reviewed. Inclusion criteria were as follows: diagnosis of Acanthamoeba Keratitis by positive confocal microscopy or culture, diagnosis of glaucoma or ocular hypertension secondary to Acanthamoeba Keratitis, and at least 6 months of follow-up. Exclusion criteria included a previous diagnosis of glaucoma or ocular hypertension and any history of intraocular surgery before the development of glaucoma. The date of Keratitis development, pneumotonometry on initial and follow-up examinations, glaucoma medications used, and surgical procedures performed were tabulated. RESULTS Twenty patients (20 eyes) were included. Six (30%) eyes developed secondary glaucoma during the review period. Of the patients treated for glaucoma with medication alone, the visual acuity of three (75%) of four became light perception or no light perception. Three of six patients required glaucoma drainage device implantation for intraocular pressure control. Of these, the vision of one eye became no light perception, and the other two eyes maintained better than 20/100 vision. Histopathologic examination showed chronic inflammation of the trabecular meshwork and angle closure. No Acanthamoeba organisms were found in the angle structures. CONCLUSIONS The development of secondary glaucoma is not uncommon in Acanthamoeba Keratitis and is a poor prognostic sign in patients with Acanthamoeba Keratitis, because most progress to light perception or no light perception vision. Histopathologic findings suggest an inflammatory angle-closure mechanism, apparently without direct infiltration of the organism. The glaucoma associated with Acanthamoeba Keratitis is often severe and frequently requires surgical intervention for intraocular pressure control and vision preservation.