Int Ophthalmol (2011) 31:51–53 DOI 10.1007/s10792-010-9398-4
CASE REPORT
Depiction of the vitreous pocket by optical coherence tomography Hiroyuki Shimada • Tokihito Hirose • Atsushi Yamamoto • Hiroyuki Nakashizuka Takayuki Hattori • Mitsuko Yuzawa
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Received: 16 January 2010 / Accepted: 4 September 2010 / Published online: 21 September 2010 Ó Springer Science+Business Media B.V. 2010
Abstract The reported shape and size of the vitreous pocket vary depending on the method of visualization. We used spectral domain optical coherence tomography (SD-OCT) to clarify the structure of the normal vitreous pocket. The macular retina of 20 consecutive non-highly myopic eyes of 10 healthy young adults (aged 22-27 years) was examined using spectral SDOCT. The premacular vitreous pocket and the prepapillary Cloquet’s canal were observed in a scan area 9 mm in transverse diameter and 6 mm in longitudinal diameter. On SD-OCT, the vitreous pocket was observed in all the eyes, anterior to the macula as a flat dish-like structure measuring 7.5 ± 0.6 mm in transverse diameter, 5.2 ± 0.3 mm in longitudinal diameter, and 0.3 ± 0.5 mm in thickness. The boundary of the vitreous pocket was clear, the central portion was thin, and the peripheral portion protruded anteriorly. The posterior wall of the vitreous pocket which can be observed at the macular region was a thin layer of vitreous cortex. Mildly reflective dots were observed inside the vitreous pocket. A thin wall was observed between the vitreous pocket and the pre-papillary Cloquet’s canal. On SD-OCT, the vitreous pocket of healthy young adults was visualized as a liquefied
H. Shimada (&) T. Hirose A. Yamamoto H. Nakashizuka T. Hattori M. Yuzawa Department of Ophthalmology, School of Medicine, Surugadai Hospital of Nihon University, 1-8-13 Surugadai, Kanda, Chiyodaku, Tokyo 101-8309, Japan e-mail:
[email protected]
lacuna with a clear boundary measuring approximately 7.5 9 5.2 9 0.3 mm, with the posterior wall composed of a layer of vitreous cortex and separated from the pre-papillary Cloquet’s canal by a thin wall. Keywords Bursa premacularis Cloquet’s canal Liquefied lacuna Optical coherence tomography Posterior precortical vitreous pocket SD-OCT
Introduction Worst was the first to confirm the presence of a liquefied lacuna surrounded by dense collagen anterior to the macula, and named this structure the ‘‘bursa premacularis’’ [1–3]. Thereafter, Kishi and Shimizu [4] described a liquefied lacuna anterior to the macula, which they called the posterior precortical vitreous pocket (vitreous pocket), and their group also reported that this structure was associated with macular hole formation [5]. Recently, we reported a three-dimensional depiction of the whole vitreous pocket obtained by direct injection of triamcinolone acetonide (TA) into the pocket during vitrectomy. The injected TA spread in the premacular vitreous pocket in the shape of a disc, and did not diffuse beyond the pocket. Our observations thus confirmed that the vitreous pocket contains a liquefied substance and an anterior wall composed of dense collagen [6]. However, many aspects of the vitreous pocket remain unknown, and the reported
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shape and size of the vitreous pocket vary depending on the method of visualization. In the present study, we observed the morphology of the vitreous pocket using spectral domain optical coherence tomography (SD-OCT).
Methods Between March and May 2009, the structure of the vitreous pocket was studied using the Cirrus SD-OCT (Carl Zeiss Meditec, Jena, Germany) in 20 normal eyes without high myopia ([–6.0 diopters) of 10 healthy young adults aged 22-27 (23.9 ± 3.2) years. Using SD-OCT, the premacular vitreous pocket and the pre-papillary Cloquet’s canal were observed within a scan area 9 mm in transverse diameter and 6 mm in longitudinal diameter. The 9 mm (transverse diameter) 9 6 mm scan (longitudinal diameter) represents the measuring limits of the Cirrus SD-OCT.
Results On SD-OCT, the vitreous pocket was observed anterior to the macula as a flat dish-like structure measuring 7.5 ± 0.6 (6.5 * 8.0) mm in transverse diameter, 5.2 ± 0.3 (5.0 * 5.5) mm in longitudinal diameter, and 0.3 ± 0.5 (0.2 * 0.4) mm in thickness. The boundary of the vitreous pocket was clear. The central portion was thin, while the peripheral portion protruded anteriorly. Mildly reflective dots were observed inside the vitreous pocket. The posterior wall of the vitreous pocket, which could be observed at the macular region, was found to be a thin layer of vitreous cortex (Fig. 1A). A thin wall was observed between the vitreous pocket and the pre-papillary Cloquet’s canal (Fig. 1B). No lacuna connected to the vitreous pocket was recognized. The above findings were observed in all the eyes studied.
Discussion The morphology of the vitreous pocket was demonstrated clinically using B-scan ultrasonography by Spaide in 2003, who also estimated the vitreous pocket to have a horizontal diameter of 10.3 mm and a vertical diameter of 11.1 mm [7]. Kishi and
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Fig. 1 Observation of the vitreous pocket by SD-OCT scan with a 9 mm transverse diameter and 6 mm longitudinal diameter. A The vitreous pocket is seen as a flat dish-shaped homogenous structure measuring 7.5 ± 0.6 mm in transverse diameter (a) and 0.3 ± 0.5 mm (c) in thickness. The posterior wall of the vitreous pocket is a thin layer of vitreous cortex. A thin wall (arrow) separates the vitreous pocket and the prepapillary Cloquet’s canal. B The vitreous pocket is observed as a flat dish-shaped homogenous structure measuring 5.2 ± 0.3 mm (b) in longitudinal diameter and 0.3 ± 0.5 mm (c) in thickness. The posterior wall of the vitreous pocket has a thin layer of vitreous cortex
Shimizu reported that the shape of the vitreous pocket was oval [4]. In 2009, we injected TA into the vitreous pocket and observed a disc-like structure with estimated dimensions of 7.0 9 5.0 9 2.0 mm [6]. Thus the reported shape and size of the vitreous pocket vary depending on the method of visualization. In the present study using SD-OCT, the vitreous pocket was depicted as a flat dish-shaped liquefied lacuna with a clear boundary measuring approximately 7.5 9 5.2 9 0.3 mm, located anterior to the macula. In our previous study, injection of TA into the vitreous pocket probably increased the volume of the vitreous pocket, resulting in a disc-like structure. We speculate that, anatomically, the normal vitreous
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pocket probably has the shape of a flat dish as depicted on SD-OCT. and that mildly reflective dots observed inside the vitreous pocket are hyaluronic acid. Thus the present data obtained by SD-OCT probably represent the true structure of the normal vitreous pocket. Future studies are required to examine the changes of the vitreous pocket with aging and in different pathological conditions. Acknowledgment This study was financed by regular departmental research funds. No financial or material support was received from other sources. Conflict of interest
None.
53 2. Worst J (1978) Extracapsular surgery in lens implantations (Binkhorst lecture). Part iv. Some anatomical and pathophysiological implications. J Am Intraocul Implant Soc 4:7–14 3. Jongebloed WL, Worst JF (1987) The cisternal anatomy of the vitreous body. Doc Ophthalmol 67:183–196 4. Kishi S, Shimizu K (1990) Posterior precortical vitreous pocket. Arch Ophthalmol 108:979–982 5. Kishi S, Hagimura N, Shimizu K (1996) The role of the premacular liquefied pocket and premacular vitreous cortex in idiopathic macular hole development. Am J Ophthalmol 122:622–628 6. Shimada H, Nakashizuka H, Hattori T et al (2009) Threedimensional depiction of the vitreous pocket using triamcinolone acetonide. Eur J Ophthalmol 19:1102–1105 7. Spaide RF (2003) Measurement of the posterior precortical vitreous pocket in fellow eyes with posterior vitreous detachment and macular holes. Retina 23:481–485
References 1. Worst JF (1977) Cisternal systems of the fully developed vitreous body in the young adult. Trans Ophthalmol Soc UK 97:550–554
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