Peripapillary gamma zone pit as dehiscence between Elschnig´s border tissue and Bruch´s membrane with herniation and defect of the retinal nerve fiber layer
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The parapapillary gamma zone has recently been defined as the parapapillary region free of Bruch’s membrane. Although it has been reported the presence of defects in peripapillary gamma zone, hitherto undescribed is the herniation of the retinal nerve fiver layer tissue into the peripapillary gamma zone defect with the resulting localized defects in the retinal nerve fiber layer.
Ophthalmoscopy in a 36-year-old man revealed a localized defect of the retinal nerve fiber layer associated with a yellowish-gray lesion at the inferior temporal outer margin of a peripapillary gamma zone. Enhanced depth imaging of spectral-domain optical coherence tomography (OCT) showed a dehiscence at the connecting point between the central end of Bruch’s membrane and the peripheral end of the border tissue of Elschnig and Jacoby. Retinal nerve fiber layer tissue was herniated through this defect into a cavitation located in the suprachoroidal space and the space above the cerebrospinal fluid space. At a 2-year follow-up examination, the defect and retinal nerve fiber layer defect appeared unchanged.
We present a peripapillary gamma zone pit originating as a dehiscence between Elschnig’s border tissue and Bruch’s membrane and associated with a herniation and defect of the retinal nerve fiber layer and with a suprachoroidal cavitation.
KeywordsGamma zone pit Peripapillary atrophy Retinal nerve fiber layer defect Suprachoroidal cavitation Myopia Case report
Previous studies have shown that the peripapillary region can be divided into a peripheral alpha zone, characterized by Bruch’s membrane covered with an irregularly structured retinal pigment epithelium; a beta zone showing Bruch’s membrane denuded of retinal pigment epithelium; and a gamma zone free of Bruch’s membrane . Recent reports by Ohno-Matsui and our group showed the presence of defects in peripapillary gamma zone [2, 3]. Here we describe a patient who showed a peripapillary gamma zone defect with herniation and defect of the retinal nerve fiber layer.
Hitherto undescribed is the herniation of the retinal nerve fiver layer tissue into the peripapillary gamma zone defect with the resulting localized defects in the retinal nerve fiber layer. It has remained unclear whether a partial blockade of the axoplasmic flow in the nerve fibers by the herniation caused the drop-out of the fibers. Also, in contrast to the patients with peripapillary pits described by Ohno-Matsui et al., who were more myopic (−9.5D to −22.0D) and had longer axial lengths (29.5 mm to 32.8 mm), our patient was not that highly myopic . The finding in our patient may suggest a peripapillary gamma zone pit can develop by a dehiscence between the border tissue of Elschnig and Bruch’s membrane at their connecting point. In our patient, peripapillary gamma zone defect may not have been caused by a schisis in the sclera or in spatial correlation with an opening of a short posterior ciliary artery as described previously [1, 3].
In conclusion, a peripapillary gamma zone pit was presented originating as a dehiscence between Elschnig’s border tissue and Bruch’s membrane and associated with a herniation and defect of the retinal nerve fiber layer and with a suprachoroidal cavitation.
OCT, optical coherence tomography
The authors thank Dr. Qing Chang for evaluating the case together.
Supported by grants from the Shanghai Science and Technology Committee (No. 16411962000).
Availability of data and materials
All the data have been presented is contained within the manuscript and in the form of images.
XH is responsible for acquisition of the clinical information and drafting the article. YD is responsible for analysis and interpretation of data, revising the manuscript. JJ and XS are responsible for reviewing the manuscript. All authors contributed to reading the final manuscript and approval of the version to be published.
The authors declare that they have no competing interests.
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Written informed consent was obtained from the patient for publication of this case report and any accompanying images. A copy of the written consent is available for review by the editor of this journal.
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