網膜色素変性に伴う嚢胞様黄斑浮腫と硝子体手術

Vitreous surgery for cystoid macular edema in a case of retinitis pigmentosa

　31歳女性が左眼の網膜色素変性の疑いで受診した。矯正視力は右1.2，左0.5であり，両眼の網膜色素上皮が粗で，網膜血管の狭窄化があった。左眼に著明な嚢胞様黄斑浮腫があった。両眼の網膜色素変性と診断した。17か月後に左眼視力が0.3に低下した。光干渉断層計（OCT）の所見から，硝子体による網膜への牽引が黄斑浮腫の悪化要因であると考えた。硝子体手術を行い，人工的に後部硝子体を剥離し，SF₆で硝子体を置換した。内境界膜剥離は行わなかった。術後黄斑浮腫は軽快し，視力0.5に改善したが，手術の4か月後に再び0.3に低下し，現在に至っている。網膜色素変性に併発した嚢胞様黄斑浮腫が，硝子体手術によって硝子体牽引が解除されても，必ずしも永続的に軽快しないことを本症例は示している。

A 31-year-old female was referred to us for suspected retinitis pigmentosa in her left eye. Her corrected visual acuity was 1.2 right and 0.5 left. Funduscopy showed coarse retinal pigment epithelium and attenuated vessels in both eyes. Pronounced cystoid macular edema (CME) was present in the left eye. She was diagnosed with bilateral retinitis pigmentosa. Her left visual acuity decreased to 0.3 17 months later. Op-tical coherence tomography (OCT) showed vitreoretinal traction as the probable cause of CME. We performed vitrectomy by creating detachment of posterior vitreous membrane and replacing the vitreous with sulfer hexafluoride. The internal limiting membrane was left intact. The CME became less conspicuous and the vis-ual acuity improved to 0.5 after surgery. The visual acuity decreased to 0.3 4 months later. This case illus-trates that CME in retinitis pigmentosa may not improve permanently after surgical release of vitreoretinal traction.