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Recurrent Corneal Erosions
Ophthalmology Volume 117, Number 2, February 2010 FRIEDERIKE MACKENSEN, MD MATTHIAS BECKER, MD STEFAN ZIMMERMANN, MD Heidelberg, Germany References 1. Ang M, Htoon HM, Chee SP. Diagnosis of tuberculous uveitis: clinical application of an interferon-gamma release assay. Ophthalmology 2009;116:1391– 6. 2. Kurup SK, Buggage RR, Clarke GL, et al. Gamma interferon assay as an alternative to PPD skin testing in selected patients with granulomatous intraocular inflammatory disease. Can J Ophthalmol 2006;41:737– 40. 3. Mackensen F, Becker MD, Wiehler U, et al. QuantiFERON TB-Gold–a new test strengthening long-suspected tuberculous involvement in serpiginous-like choroiditis. Am J Ophthalmol 2008;146:761– 6. 4. Itty S, Bakri SJ, Pulido JS, et al. Initial results of QuantiFERON-TB Gold testing in patients with uveitis. Eye 2009;23:904 –9.
Author reply Dear Editor: We would first like to apologize for the oversight on the inadvertent deletion of the references mentioned by Mackensen1,2 during the process of multiple revisions of the paper prior to submission. Our statement, “the role of IGRAs [Interferon-␥ release assays] in the diagnosis of TB [tuberculous] uveitis is not well studied” was made in relative terms to the study of IGRA in other fields of medicine. The role of IGRAs is relatively less well studied in TB uveitis, compared with pulmonary or other forms of TB. In our discussion, we mainly compared the use of QuantiFERON (QFT) Gold test or IGRA to existing methods of diagnosing TB and latent TB, such as the tuberculin skin test or radiological investigations. Thus, we cited papers such as those by Pai et al3 and Dosanjh et al4 published in Annals of Internal Medicine in 2008, which we feel are important and pertinent to our manuscript. We also made the statement that, to our knowledge our study, “is the first and largest study of its kind to evaluate the use of QFT in the clinical diagnosis of uveitis.” We recognize that there are several studies including those mentioned by Mackensen,1 which have evaluated the use of QFT in TB uveitis. Our use of the phrase “first study of its kind” is in reference to the systematic analysis of consecutive “suspected TB uveitis” patients by means of a new methodology of using treatment response and outcomes. SOON-PHAIK CHEE, FRCOPHTH MARCUS ANG, MBBS Singapore, Singapore References 1. Mackensen F, Becker MD, Wiehler U, et al. QuantiFERON TB-Gold–a new test strengthening long-suspected tuberculous involvement in serpiginous-like choroiditis. Am J Ophthalmol 2008;146:761– 6. 2. Itty S, Bakri SJ, Pulido JS, et al. Initial results of QuantiFERON-TB Gold testing in patients with uveitis. Eye 2009;23:904 –9. 3. Pai M, Zwerling A, Menzies D. Systematic review: T-cellbased assays for the diagnosis of latent tuberculosis infection: an update. Ann Intern Med 2008;149:177– 84.
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4. Dosanjh DP, Hinks TS, Innes JA, et al. Improved diagnostic evaluation of suspected tuberculosis. Ann Intern Med 2008;148:325–36.
Recurrent Corneal Erosions Dear Editor: The paper describing the use of the YAG laser to treat recurrent erosions by Tsai et al,1 is similar to a paper written approximately 15 years ago by myself and coauthors.2 The results of their series of 33 eyes were similar to the smaller series of 8 eyes in our study. Our paper did, however, discuss the histopathology of the YAG laser lesions in the human eye, and revisiting that information in the context of this more recent clinical study may be useful to the reader. The mechanism of action and safety of the procedure was studied in the paper by Katz et al as follows. A patient scheduled for an enucleation due to a choroidal mass consented to undergo simulation of the YAG laser treatment for recurrent erosion using different laser energy settings. 60 laser applications to each quadrant of the cornea using 0.5 mJ, 1.0 mJ, 1.8 mJ, and 2.5 mJ, respectively, were used. Six days later the eye was enucleated and the cornea was sectioned for light and electron microscopy at the ocular pathology lab at the Wilmer Ophthalmological Institute. Breaks in Bowman’s layer only occurred with the higher energy levels. New collagen formation with fine fibrils extending from basal epithelial cells to the areas of new collagen formation were seen on electron microscopy in quadrants of the cornea treated with lower energy levels. We concluded that a break in Bowman’s layer is not required for the YAG laser to be effective in the treatment of recurrent erosions and, in fact, may be an undesirable consequence if it occurs. We recommended the use of the lowest energy settings of the YAG laser in order to prevent the disruption of Bowman’s membrane with subsequent scarring. This information concerning the mechanism of action, the safety and the basis for the laser parameters should be included in the discussion by Tsai et al. Their title may be inappropriate since the paper by Katz et al indicated that the laser energy levels used in the current study would not penetrate through Bowman’s layer into the superficial corneal stroma. The term “photo-induced adhesion of the corneal epithelium” used in the paper by Katz et al may be more accurate. HAROLD KATZ, MD Baltimore, Maryland References 1. Tsai TY, Tsai TH, Hu FR, et al. Recurrent corneal erosions treated with anterior stromal puncture by neodymium: yttriumaluminum-garnet laser. Ophthalmology 2009;116:1296 –300. 2. Katz HR, Snyder ME, Green WR, et al. Nd:YAG laser photoinduced adhesion of the corneal epithelium. Am J Ophthalmol 1994;118:612–22.
Author reply Dear Editor: We thank Dr. Katz for his interest and comments in our recent article regarding treatment effect of recurrent corneal erosion
Author reply Dear Editor: We would first like to apologize for the oversight on the inadvertent deletion of the references mentioned by Mackensen1,2 during the process of multiple revisions of the paper prior to submission. Our statement, “the role of IGRAs [Interferon-␥ release assays] in the diagnosis of TB [tuberculous] uveitis is not well studied” was made in relative terms to the study of IGRA in other fields of medicine. The role of IGRAs is relatively less well studied in TB uveitis, compared with pulmonary or other forms of TB. In our discussion, we mainly compared the use of QuantiFERON (QFT) Gold test or IGRA to existing methods of diagnosing TB and latent TB, such as the tuberculin skin test or radiological investigations. Thus, we cited papers such as those by Pai et al3 and Dosanjh et al4 published in Annals of Internal Medicine in 2008, which we feel are important and pertinent to our manuscript. We also made the statement that, to our knowledge our study, “is the first and largest study of its kind to evaluate the use of QFT in the clinical diagnosis of uveitis.” We recognize that there are several studies including those mentioned by Mackensen,1 which have evaluated the use of QFT in TB uveitis. Our use of the phrase “first study of its kind” is in reference to the systematic analysis of consecutive “suspected TB uveitis” patients by means of a new methodology of using treatment response and outcomes. SOON-PHAIK CHEE, FRCOPHTH MARCUS ANG, MBBS Singapore, Singapore References 1. Mackensen F, Becker MD, Wiehler U, et al. QuantiFERON TB-Gold–a new test strengthening long-suspected tuberculous involvement in serpiginous-like choroiditis. Am J Ophthalmol 2008;146:761– 6. 2. Itty S, Bakri SJ, Pulido JS, et al. Initial results of QuantiFERON-TB Gold testing in patients with uveitis. Eye 2009;23:904 –9. 3. Pai M, Zwerling A, Menzies D. Systematic review: T-cellbased assays for the diagnosis of latent tuberculosis infection: an update. Ann Intern Med 2008;149:177– 84.
402
4. Dosanjh DP, Hinks TS, Innes JA, et al. Improved diagnostic evaluation of suspected tuberculosis. Ann Intern Med 2008;148:325–36.
Recurrent Corneal Erosions Dear Editor: The paper describing the use of the YAG laser to treat recurrent erosions by Tsai et al,1 is similar to a paper written approximately 15 years ago by myself and coauthors.2 The results of their series of 33 eyes were similar to the smaller series of 8 eyes in our study. Our paper did, however, discuss the histopathology of the YAG laser lesions in the human eye, and revisiting that information in the context of this more recent clinical study may be useful to the reader. The mechanism of action and safety of the procedure was studied in the paper by Katz et al as follows. A patient scheduled for an enucleation due to a choroidal mass consented to undergo simulation of the YAG laser treatment for recurrent erosion using different laser energy settings. 60 laser applications to each quadrant of the cornea using 0.5 mJ, 1.0 mJ, 1.8 mJ, and 2.5 mJ, respectively, were used. Six days later the eye was enucleated and the cornea was sectioned for light and electron microscopy at the ocular pathology lab at the Wilmer Ophthalmological Institute. Breaks in Bowman’s layer only occurred with the higher energy levels. New collagen formation with fine fibrils extending from basal epithelial cells to the areas of new collagen formation were seen on electron microscopy in quadrants of the cornea treated with lower energy levels. We concluded that a break in Bowman’s layer is not required for the YAG laser to be effective in the treatment of recurrent erosions and, in fact, may be an undesirable consequence if it occurs. We recommended the use of the lowest energy settings of the YAG laser in order to prevent the disruption of Bowman’s membrane with subsequent scarring. This information concerning the mechanism of action, the safety and the basis for the laser parameters should be included in the discussion by Tsai et al. Their title may be inappropriate since the paper by Katz et al indicated that the laser energy levels used in the current study would not penetrate through Bowman’s layer into the superficial corneal stroma. The term “photo-induced adhesion of the corneal epithelium” used in the paper by Katz et al may be more accurate. HAROLD KATZ, MD Baltimore, Maryland References 1. Tsai TY, Tsai TH, Hu FR, et al. Recurrent corneal erosions treated with anterior stromal puncture by neodymium: yttriumaluminum-garnet laser. Ophthalmology 2009;116:1296 –300. 2. Katz HR, Snyder ME, Green WR, et al. Nd:YAG laser photoinduced adhesion of the corneal epithelium. Am J Ophthalmol 1994;118:612–22.
Author reply Dear Editor: We thank Dr. Katz for his interest and comments in our recent article regarding treatment effect of recurrent corneal erosion