微小視野計MP-1で測定した偏心固視症例における固視と視力，読書能力との関係

Correlation between visual acuity and reading ability versus status of fixation as measured by microperimeter MP-1 in eyes with eccentric fixation

要約　目的：非典型偏心固視者の遠見視力と読書能力と，固視状況との相関の報告。対象と方法：中心暗点がある17例21眼を対象とした。男性12例，女性5例で，年齢は31～92歳（平均67歳）である。9例が加齢黄斑変性であった。MN read-Jで最大読書速度，微小視野計MP-1で固視偏心度と固視安定度を測定した。遠見視力はlogMARで評価した。結果：視力は0.5～1.5（平均0.95）で，最大読書速度は毎分6.4～225字（平均93字）であった。固視偏心度は1.1～15.5°（平均6.0°），固視安定度は直径2°で11～98％（平均57.6％）であった。視力と最大読書速度は，固視偏心度と有意な相関があった。最大読書速度と4°での固視安定度には弱い相関があり，視力とは相関しなかった。結論：中心暗点がある偏心固視者の視力と読書能力は，固視安定度よりも固視偏心度が強く相関する。

Abstract.　Purpose：To report correlation among visual acuity, reading ability and status of fixation in eyes with eccentric fixation. Cases and Method：This study was made on 21 eyes of 17 persons with bilateral central scotoma. The series comprised 12 males and 5 females. The age ranged from 31 to 92 years, average 67 years. Age-related macular degeneration was present in 9 cases. Maximum reading ability was measured with MN read-J. Status and stability of fixation was measured with a microperimeter MP-1. Visual acuity for distance was expressed as logMAR. Results：Visual acuity ranged from 0.5 to 1.5, average 0.95. Maximum reading ability averaged 93 letters per minute. Degree of eccentric fixation was strongly correlated with visual acuity and maximum reading speed. Stability of eccentric fixation was weakly correlated with maximum reading speed only. Conclusion：Visual acuity and reading ability are more strongly correlated with degree of eccentric fixation than stability of fixation in persons with eccentric fixation.