ガラクトシアリドーシスの1例―視機能とロービジョンケア

Visual function and low vision care in a case of galactosialidosis

要約　目的：視機能とロービジョンケアについて検討したガラクトシアリドーシス症例の報告。症例：18歳男性。羞明と視力低下のため当科を受診した。初診時，両眼矯正視力は0.1，両眼眼底には黄斑部に桜実紅斑（cherry-red spot）を認めた。色覚検査では分類不能な色覚異常，Humphrey視野検査では縞状の感度低下を認めた。全視野網膜電図は正常範囲下限値を示したが，後極部網膜電図は視角10°と20°刺激で有意な振幅低下を示した。羞明や近見・遠見視力低下に対し，遮光眼鏡，手持ち式拡大鏡と単眼鏡を処方した。結論：眼底後極部の錐体系反応が主に障害されていた本症例では，日常生活の問題点に対応したロービジョンエイドの処方が有効であった。

Abstract.　Purpose：To report visual function and the care for low vision in a case of galactosialidosis. Case：A 18-year-old male presented with photophobia and impaired visual acuity. His corrected visual acuity was 0.1 in either eye. Granular opacity was present in both corneas. The fundus showed cherry-red spot in both eyes. Color vision test showed color abnormality of unclassified nature. Humphrey visual field showed focal loss of sensitivity. Full-field electroretinogram was within normal limits. Electroretinogram from posterior fundus within 20 degrees was significantly reduced. The findings led to the tentative diagnosis of galactosialidosis. To relieve photophobia and impaired visual acuity, he was prescribed with shaded eyeglasses, mono-ocular eyeglasses, and hand-held magnifier. Conclusion：Impaired cone function was the cardinal feature in this case. Low vision aids were useful in his daily life.