Radial scan OCTにより網膜神経線維層の伸展と菲薄化がみられたperipapillary choroidal cavitationの2症例

Two cases of peripapillary choroidal cavitation with stretched and thinned retinal nerve fiber layers detected by radial scan optical coherence tomograph

要約　目的：Peripapillary choroidal cavitation（PCC）部分で網膜神経線維層の伸展と菲薄化を光干渉断層計（OCT）で認め，視野障害への影響が推定された2症例の報告。

症例：強度近視を伴う緑内障眼の視神経乳頭にradial scan OCTを施行し，脈絡膜内に空隙形成を認め，PCCと診断した。PCC部分では網膜神経線維がハンモック状に牽引・伸長されており，この部分に一致した網膜神経線維層厚の菲薄化が認められ，視野障害への影響が推定された。

結論：PCCでみられる緑内障様視野障害には，脈絡膜の空隙形成に伴う網膜神経線維の機械的伸展が関与している可能性がある。

Abstract　Purpose: To report two glaucoma cases with peripapillary choroidal cavitation（PCC）in which retinal nerve fibers were stretched and thinned at the lesion and were suggestive of its influence on the visual field defects.

Cases: Radial scan optical coherent tomograph（OCT）centered on the optic discs were performed to the glaucoma eyes with high myopia. Choroidal cavitation was observed in these eyes, and they were diagnosed as PCC. At the PCC lesion, retinal nerve fibers were stretched and presented as the hammock-like figures. The retinal nerve fiber layers were thinned at the PCC lesion, suggesting the influence on the corresponding visual field defect.

Conclusion: In the eyes with PCC, the mechanical stretching of the retinal nerve fibers at the choroidal cavitation area might be responsible to the glaucomatous visual field defects.