behind silicone oil bubbles. In Dr. Errera’s article, Figure 4, B and C showed this phenomenon but were not described in the text. Hyperreflective tails behind hyperreflective dots is a peculiar optical effect. The tail-like phenomenon has also been described in some cases with retained perfluorocarbon liquid, however without clear explanation.2 We believe “multiple scattering” could be one possible explanation for this artifact.3 When light penetrates a bubble, strong reflections are seen from the initial and back surface of the sphere; however, some rays may scatter within the bubble before returning to the optical coherence tomography sensor. Because time is represented as distance in these devices, multiple artifact images may form behind the bubble. A hyperreflective tail should also be distinguished from increased light penetration, which can be routinely seen in atrophic areas imaged by optical coherence tomography. Although artifact tails may obscure deeper retinal–choroidal structures, increased penetration makes them more visible. According to our observation, emulsified silicone oil may have several types of manifestation during optical coherence tomography imaging described below.
Correspondence To the Editor: We read with great interest the recent article by Dr. Marie-Hélène Errera et al1 entitled “Using spectraldomain optical coherence tomography imaging to identify the presence of retinal silicone oil emulsification after silicone oil tamponade.” They were able to demonstrate small hyperreflective areas intraretinally, subretinally, and underneath the epiretinal membranes on spectral domain optical coherence tomography in eyes that have had silicone oil tamponade and hypothesized that the hyperreflective areas are likely to be very small bubbles of emulsified silicone. Coincidently, we have found exactly the same spectral domain optical coherence tomography findings in patients with emulsified silicone oil. In our cases, we demonstrate increased hyperreflectivity intraretinally, which we believe correspond to silicone oil droplets within the retina. In addition, we were able to image these droplets using adaptive optics (Figure 1). Although increased reflectivity could be caused by other recognized elements such as hemorrhages or lipid exudates, these changes usually demonstrate shadowing, which occurs immediately behind strong light reflectors during retinal optical coherence tomography imaging. In particular, hyperreflective comet-like “tails” often occur
1. Clear bubbles with/without hyperreflective tails. 2. Hyperreflective dots with/without hyperreflective tails. 3. Hyperreflective tails without observable dots or bubbles.
Fig. 1. A 58-year-old high myopic woman underwent pars plana vitrectomy with silicone oil tamponade for retinal detachment in her right eye. Removal surgery was performed 2 years later because of emulsification. One month after silicone oil removal, color photograph (A) shows flat retina without visible oil droplets, but ultrasound (B) demonstrates obvious highly reflective dots in the vitreous cavity. Optical coherence tomography (D) line-scan (green line in A) shows hyperreflective dots (white arrow) followed by hyperreflective tail (yellow arrows). Inferred camera with adaptive optics (C) confirms droplets in the retina (red arrow).
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Optical coherence tomography manifestations seem to depend on characteristics of the substance, bubble size, and light source. We agree with Dr. Errera that variation in hyperreflectivity with bubble size may explain the discrepancy.4 Bandwidth, wavelength, and incident angle of light source may also contribute to different representation. Emulsified silicone oil may be imaged in many ocular tissues. Representation varies with techniques.5 Interpretation of these images is very important for the retinal specialist to fully understand the possible impact of emulsified silicone oil on retina and its function. At present, we believe that ultrasound is the best way to demonstrate emulsified silicone oil droplets in the vitreous cavity. Optical coherence tomography is useful for detecting them in retina and optic nerve, and adaptive optics is an additional and confirming imaging method if available. Suqin Yu, MD*† Yale L. Fisher, MD*‡ *Department of Ophthalmology, Vitreous Retina Macula Consultants of New York, New York, New York †Shanghai Jiao Tong University affiliated Shanghai First People’s Hospital, Shanghai, China ‡LuEsther T. Mertz Retinal Research Center, Manhattan Eye Ear and Throat Hospital, New York, New York Supported by K. C. Wong Education Foundation, Hong Kong, LuEsther T. Mertz Retinal Research Center, New York, NY, and The Macular Foundation, Inc. None of the authors have any conflicting interests to disclose. References 1. Errera MH, Liyanage SE, Elgohary M, et al. Using spectraldomain optical coherence tomography imaging to identify the presence of retinal silicone oil emulsification after silicone oil tamponade. Retina 2013;33:1567–1573. 2. Figueroa MS, Contreras I. Characteristics of retained subretinal perfluoro-n-octane on optical coherence tomography. Retina 2012;32:2177–2178. 3. Huang Y. Optidcal coherence tomogramphy (OCT) in hereditary retinal degenerations: layer-by-layer analyses in normal and diseased retinas. Aissertation in Bioengineering. Presented to the faculties of the University of Pennsylvania in partial fulfillment of the requirements for the degree of Doctor of Philosophy. 1999. 4. Chung J, Spaide R. Intraretinal silicone oil vacuoles after macular hole surgery with intral limiting membrane peeling. Am J Ophthalmol 2003;136:766–767. 5. Spaide RF, Chung JE, Fisher YL. Ultrasound detection of silicone oil after its removal in retinal reattachment surgery. Retina 2005;25:943–945.
Reply To the Editor: We read with great interest the recent letter to the Editor by Yu et al, which comments on our study entitled “Using spectral-domain optical coherence tomography (SD-OCT) imaging to identify the presence of retinal silicone oil emulsification after silicone oil tamponade.”1 We are thankful for their interest in our study. They confirm our finding that silicone oil emulsion appears as hyperreflective dots on spectral domain optical coherence tomography. Additionally, they highlighted the finding of hyperreflective tails behind silicone droplets, which can be attributed to internal reflection of light within silicone bubbles. This is a very interesting finding, which to the best of our knowledge is specific to silicone bubbles. This may help to better understand the process of silicone engulfment in retinal tissue and its possible implication in proliferative vitreoretinopathy. Although they also show that these silicone oil droplets can be detected by Adaptive Optics imaging, this offers the possibility to document intraretinal migration of these droplets by time-lapse imaging. Marie-Helene Errera, MD*† Sidath E. Liyanage, BSc, MBBS, FRCOphth*‡ Mostafa Elgohary, MBChB, MS, MD, FRCSEd, FRCSI, FRCOphth* Alexander C. Day, MRCOphth*‡ Louisa Wickham, MD, MSc* Praveen J. Patel, MB BChir, MA, FRCOphth, MD*‡ José-Alain Sahel, MD* Michel Paques, MD, PhD* Eric Ezra, MA, MD, FRCS, FRCOphth* Paul M. Sullivan, MD, FRCOphth* *Moorfields Eye Hospital, London, United Kingdom †Sorbonne Universités, UPMC Univ Paris 06, INSERM, CIC 1423, Centre Hospitalier National des Quinze-Vingts, Paris, France ‡NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital and UCL Institute of Ophthalmology, London, United Kingdom None of the authors have any financial/conflicting interests to disclose. Reference 1. Errera MH, Liyanage SE, Elgohary M, et al. Using spectraldomain optical coherence tomography imaging to identify the presence of retinal silicone oil emulsification after silicone oil tamponade. Retina 2013;33:1567–1573.
Correspondence To the Editor: We read with great interest the recent article by Dr. Marie-Hélène Errera et al1 entitled “Using spectraldomain optical coherence tomography imaging to identify the presence of retinal silicone oil emulsification after silicone oil tamponade.” They were able to demonstrate small hyperreflective areas intraretinally, subretinally, and underneath the epiretinal membranes on spectral domain optical coherence tomography in eyes that have had silicone oil tamponade and hypothesized that the hyperreflective areas are likely to be very small bubbles of emulsified silicone. Coincidently, we have found exactly the same spectral domain optical coherence tomography findings in patients with emulsified silicone oil. In our cases, we demonstrate increased hyperreflectivity intraretinally, which we believe correspond to silicone oil droplets within the retina. In addition, we were able to image these droplets using adaptive optics (Figure 1). Although increased reflectivity could be caused by other recognized elements such as hemorrhages or lipid exudates, these changes usually demonstrate shadowing, which occurs immediately behind strong light reflectors during retinal optical coherence tomography imaging. In particular, hyperreflective comet-like “tails” often occur
1. Clear bubbles with/without hyperreflective tails. 2. Hyperreflective dots with/without hyperreflective tails. 3. Hyperreflective tails without observable dots or bubbles.
Fig. 1. A 58-year-old high myopic woman underwent pars plana vitrectomy with silicone oil tamponade for retinal detachment in her right eye. Removal surgery was performed 2 years later because of emulsification. One month after silicone oil removal, color photograph (A) shows flat retina without visible oil droplets, but ultrasound (B) demonstrates obvious highly reflective dots in the vitreous cavity. Optical coherence tomography (D) line-scan (green line in A) shows hyperreflective dots (white arrow) followed by hyperreflective tail (yellow arrows). Inferred camera with adaptive optics (C) confirms droplets in the retina (red arrow).
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Optical coherence tomography manifestations seem to depend on characteristics of the substance, bubble size, and light source. We agree with Dr. Errera that variation in hyperreflectivity with bubble size may explain the discrepancy.4 Bandwidth, wavelength, and incident angle of light source may also contribute to different representation. Emulsified silicone oil may be imaged in many ocular tissues. Representation varies with techniques.5 Interpretation of these images is very important for the retinal specialist to fully understand the possible impact of emulsified silicone oil on retina and its function. At present, we believe that ultrasound is the best way to demonstrate emulsified silicone oil droplets in the vitreous cavity. Optical coherence tomography is useful for detecting them in retina and optic nerve, and adaptive optics is an additional and confirming imaging method if available. Suqin Yu, MD*† Yale L. Fisher, MD*‡ *Department of Ophthalmology, Vitreous Retina Macula Consultants of New York, New York, New York †Shanghai Jiao Tong University affiliated Shanghai First People’s Hospital, Shanghai, China ‡LuEsther T. Mertz Retinal Research Center, Manhattan Eye Ear and Throat Hospital, New York, New York Supported by K. C. Wong Education Foundation, Hong Kong, LuEsther T. Mertz Retinal Research Center, New York, NY, and The Macular Foundation, Inc. None of the authors have any conflicting interests to disclose. References 1. Errera MH, Liyanage SE, Elgohary M, et al. Using spectraldomain optical coherence tomography imaging to identify the presence of retinal silicone oil emulsification after silicone oil tamponade. Retina 2013;33:1567–1573. 2. Figueroa MS, Contreras I. Characteristics of retained subretinal perfluoro-n-octane on optical coherence tomography. Retina 2012;32:2177–2178. 3. Huang Y. Optidcal coherence tomogramphy (OCT) in hereditary retinal degenerations: layer-by-layer analyses in normal and diseased retinas. Aissertation in Bioengineering. Presented to the faculties of the University of Pennsylvania in partial fulfillment of the requirements for the degree of Doctor of Philosophy. 1999. 4. Chung J, Spaide R. Intraretinal silicone oil vacuoles after macular hole surgery with intral limiting membrane peeling. Am J Ophthalmol 2003;136:766–767. 5. Spaide RF, Chung JE, Fisher YL. Ultrasound detection of silicone oil after its removal in retinal reattachment surgery. Retina 2005;25:943–945.
Reply To the Editor: We read with great interest the recent letter to the Editor by Yu et al, which comments on our study entitled “Using spectral-domain optical coherence tomography (SD-OCT) imaging to identify the presence of retinal silicone oil emulsification after silicone oil tamponade.”1 We are thankful for their interest in our study. They confirm our finding that silicone oil emulsion appears as hyperreflective dots on spectral domain optical coherence tomography. Additionally, they highlighted the finding of hyperreflective tails behind silicone droplets, which can be attributed to internal reflection of light within silicone bubbles. This is a very interesting finding, which to the best of our knowledge is specific to silicone bubbles. This may help to better understand the process of silicone engulfment in retinal tissue and its possible implication in proliferative vitreoretinopathy. Although they also show that these silicone oil droplets can be detected by Adaptive Optics imaging, this offers the possibility to document intraretinal migration of these droplets by time-lapse imaging. Marie-Helene Errera, MD*† Sidath E. Liyanage, BSc, MBBS, FRCOphth*‡ Mostafa Elgohary, MBChB, MS, MD, FRCSEd, FRCSI, FRCOphth* Alexander C. Day, MRCOphth*‡ Louisa Wickham, MD, MSc* Praveen J. Patel, MB BChir, MA, FRCOphth, MD*‡ José-Alain Sahel, MD* Michel Paques, MD, PhD* Eric Ezra, MA, MD, FRCS, FRCOphth* Paul M. Sullivan, MD, FRCOphth* *Moorfields Eye Hospital, London, United Kingdom †Sorbonne Universités, UPMC Univ Paris 06, INSERM, CIC 1423, Centre Hospitalier National des Quinze-Vingts, Paris, France ‡NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital and UCL Institute of Ophthalmology, London, United Kingdom None of the authors have any financial/conflicting interests to disclose. Reference 1. Errera MH, Liyanage SE, Elgohary M, et al. Using spectraldomain optical coherence tomography imaging to identify the presence of retinal silicone oil emulsification after silicone oil tamponade. Retina 2013;33:1567–1573.
