正常眼圧緑内障において視神経乳頭周囲に網膜分離および中心窩剝離を生じた1例

Peripapilary retinoschisis and macular detachment in normal tension glaucoma

要約　目的：正常眼圧緑内障の片眼に網膜分離と黄斑部の網膜剝離が併発した症例の報告。

症例：71歳の女性が右眼の視力低下で紹介され受診した。15年前から両眼の緑内障として他医で加療中であり，当初の矯正視力は左右とも1.2であったという。

所見と経過：矯正視力は右0.3，左0.7であった。光干渉断層計で右眼の黄斑部に網膜剝離と，乳頭周囲に網膜分離があった。網膜の内層分離は，視神経線維層欠損部位から鼻側に広がり，網膜外層分離の範囲は乳頭の下方を中心に鼻側と耳側に均等に広がっていた。Optic disc pit maculopathyに類似する疾患と考え，硝子体手術を実施した。術後に黄斑円孔が生じたが，内境界膜の自家移植とガスタンポナーデにより円孔は閉鎖し，右眼視力は0.5に改善した。

結論：乳頭にpitがなくても，正常眼圧緑内障では，経過中にoptic disc pit maculopathy様の網膜分離や網膜剝離が生じうることを本症例は示している。

Abstract　Purpose：To report a case of normal-tension glaucoma who developed retinoschisis and retinal detachment of the macula in one eye during the course of treatment.

Case：A 71-year-old woman was referred to us for impaired vision in the right eye. She had been treated for glaucoma in both eyes since 15 years before. Her initial corrected visual acuity was reportedly 1.2 in either eye.

Findings and Clinical Course：Corrected visual acuity was 0.3 right and 0.7 left. By optical coherence tomography, the right eye showed macular detachment and retinoschisis in the peripapillary area. Schisis of the inner retinal layer extended nasally from the area of defective retinal nerve fiber layer. Outer retinoschisis spread nasal and temporal from 6 o'clock position. The fundus lesion was diagnosed as similar to optic disc pit maculopathy and was treated by vitreous surgery. Surgery was followed by macular hole, which resolved after autotransplantation of inner limiting membrane and gas tamponade. Right visual acuity improved to 0.5.

Conclusion：This case illustrates that normal-tension glaucoma may be manifest retinoschisis or retinal detachment simulating optic disc pit maculopathy.