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Optical coherence tomography under general anesthesia in a child with nystagmus
optic disk, or retinal nerve fiber layer. The authors detected “mild” residual subretinal fluid, but whether this actually corresponds to the macular area was not mentioned. The authors agree that obtaining a reproducible and repeatable scan image for follow-up is not feasible, which is a major drawback. Alternative modern imaging tools such as RetCam (Massie Research Laboratories, Dublin, California, USA) can effectively document various pediatric retinal disorders in a noninvasive manner. When indicated, fundus fluorescein angiography under RetCam visualization can aid in the diagnosis. Oral FFA is another alternative in children. OCT scans obtained under sedation may eliminate the risk of general anesthesia. Repeatedly exposing a patient to the risks of general anesthesia for follow-up without any clear benefit for diagnosis or definition of the management strategy is debatable.
in ERM surgery.3 Electron microscopy was particularly useful in demonstrating ILM fragments within the ERM as well as detecting cellular debris and fragments of Müller cells within both the ILM and ERM specimens. A study by Haritoglou and coworkers4 also carried out electron microscopy on ILM specimens; these authors evaluated trypan blue staining for ERM surgery, and small fragments of Müller cells were also observed. Although we did not observe any residual posterior vitreous cortex in our ILM specimens, vitreous collagens at the vitreal surface could be seen in the some of the ILM specimens in previous study.4 This may be due to variations in the vitreoretinal interface in different cases of ERM, because the collagen layer was not found in the ERM and ILM specimens that were removed en bloc.4 Further studies will be beneficial in clarifying the role of posterior vitreous cortex in ERM formation and recurrence. ALVIN K.H. KWOK, MD, FRCS
PARUL SONY, MD PARIJAT CHANDRA, MD RAJ VARDHAN AZAD, MD, FRCS
Hong Kong, People’s Republic Of China
New Delhi, India
TIMOTHY Y.Y. LAI, MMEDSC, MRCS
REFERENCES REFERENCES
1. Puliafito CA, Hee MR, Lin CP, et al. Imaging of macular diseases with optical coherence tomography. Ophthalmology 1995;102:217–229.
1. Kwok AK, Lai TY, Li WW, Woo DC, Chan NR. Indocyanine green-assisted internal limiting membrane removal in epiretinal membrane surgery: a clinical and histologic study. Am J Ophthalmol 2004;138:194 –199. 2. Mori K, Gehlbach PL, Sano A, Deguchi T, Yoneya S. Comparison of epiretinal membranes of differing pathogenesis using optical coherence tomography. Retina 2004;24:57– 62. 3. Kwok AK, Lai TY, Li WW, Yew DT, Wong VW. Trypan blue- and indocyanine green-assisted epiretinal membrane surgery: clinical and histopathological studies. Eye 2004;18: 882– 888. 4. Haritoglou C, Gandorfer A, Schaumberger M, et al. Trypan blue in macular pucker surgery: an evaluation of histology and functional outcome. Retina 2004;24:582–590.
AUTHOR REPLY EDITOR: WE READ WITH INTEREST THE COMMENTS BY DR. SONY AND
associates. The real-time gray-scale view on the optical coherence tomography scanner (OCT model 3000, Carl Zeiss, Germany) used in our patient was sufficient to image the disk and arcades, allowing us to confirm that the scan was in the region of the fovea, but we agree that improvements in the real-time viewing such as increased resolution and color should be considered. The use of RetCam (Massie Research Laboratories, Dublin, California, USA) is potentially difficult in the case we described, in which the child was uncooperative and had vigorous nystagmus. Sedation instead of a general anesthetic is, in our view, not a good alternative because it cannot guarantee absolute akinesia. Finally, we emphasized the point that our technique should be considered for diagnosis rather than follow-up; hence, the risk of “repeat” general anesthesia is irrelevant.
Optical Coherence Tomography Under General Anesthesia in a Child With Nystagmus EDITOR: A RECENT ARTICLE BY C. K. PATEL, S. D. M. CHEN, AND A. D.
Farmery, “Optical Coherence Tomography Under General Anesthesia in a Child With Nystagmus” (Am J Ophthalmol 2004;137:1127–1129), offers a novel method for performing optical coherence tomography (OCT), especially in children and uncooperative adults. OCT provides near-histologic details of the posterior segment, allowing a better understanding of various disease entities.1 The majority of its applications relate to imaging of macula, 390
AMERICAN JOURNAL
CHETAN K. PATEL SIMON D. M. CHEN ANDREW D. FARMERY
Oxford, United Kingdom
OF
OPHTHALMOLOGY
FEBRUARY 2005
in ERM surgery.3 Electron microscopy was particularly useful in demonstrating ILM fragments within the ERM as well as detecting cellular debris and fragments of Müller cells within both the ILM and ERM specimens. A study by Haritoglou and coworkers4 also carried out electron microscopy on ILM specimens; these authors evaluated trypan blue staining for ERM surgery, and small fragments of Müller cells were also observed. Although we did not observe any residual posterior vitreous cortex in our ILM specimens, vitreous collagens at the vitreal surface could be seen in the some of the ILM specimens in previous study.4 This may be due to variations in the vitreoretinal interface in different cases of ERM, because the collagen layer was not found in the ERM and ILM specimens that were removed en bloc.4 Further studies will be beneficial in clarifying the role of posterior vitreous cortex in ERM formation and recurrence. ALVIN K.H. KWOK, MD, FRCS
PARUL SONY, MD PARIJAT CHANDRA, MD RAJ VARDHAN AZAD, MD, FRCS
Hong Kong, People’s Republic Of China
New Delhi, India
TIMOTHY Y.Y. LAI, MMEDSC, MRCS
REFERENCES REFERENCES
1. Puliafito CA, Hee MR, Lin CP, et al. Imaging of macular diseases with optical coherence tomography. Ophthalmology 1995;102:217–229.
1. Kwok AK, Lai TY, Li WW, Woo DC, Chan NR. Indocyanine green-assisted internal limiting membrane removal in epiretinal membrane surgery: a clinical and histologic study. Am J Ophthalmol 2004;138:194 –199. 2. Mori K, Gehlbach PL, Sano A, Deguchi T, Yoneya S. Comparison of epiretinal membranes of differing pathogenesis using optical coherence tomography. Retina 2004;24:57– 62. 3. Kwok AK, Lai TY, Li WW, Yew DT, Wong VW. Trypan blue- and indocyanine green-assisted epiretinal membrane surgery: clinical and histopathological studies. Eye 2004;18: 882– 888. 4. Haritoglou C, Gandorfer A, Schaumberger M, et al. Trypan blue in macular pucker surgery: an evaluation of histology and functional outcome. Retina 2004;24:582–590.
AUTHOR REPLY EDITOR: WE READ WITH INTEREST THE COMMENTS BY DR. SONY AND
associates. The real-time gray-scale view on the optical coherence tomography scanner (OCT model 3000, Carl Zeiss, Germany) used in our patient was sufficient to image the disk and arcades, allowing us to confirm that the scan was in the region of the fovea, but we agree that improvements in the real-time viewing such as increased resolution and color should be considered. The use of RetCam (Massie Research Laboratories, Dublin, California, USA) is potentially difficult in the case we described, in which the child was uncooperative and had vigorous nystagmus. Sedation instead of a general anesthetic is, in our view, not a good alternative because it cannot guarantee absolute akinesia. Finally, we emphasized the point that our technique should be considered for diagnosis rather than follow-up; hence, the risk of “repeat” general anesthesia is irrelevant.
Optical Coherence Tomography Under General Anesthesia in a Child With Nystagmus EDITOR: A RECENT ARTICLE BY C. K. PATEL, S. D. M. CHEN, AND A. D.
Farmery, “Optical Coherence Tomography Under General Anesthesia in a Child With Nystagmus” (Am J Ophthalmol 2004;137:1127–1129), offers a novel method for performing optical coherence tomography (OCT), especially in children and uncooperative adults. OCT provides near-histologic details of the posterior segment, allowing a better understanding of various disease entities.1 The majority of its applications relate to imaging of macula, 390
AMERICAN JOURNAL
CHETAN K. PATEL SIMON D. M. CHEN ANDREW D. FARMERY
Oxford, United Kingdom
OF
OPHTHALMOLOGY
FEBRUARY 2005