末期開放隅角緑内障眼での中心視力と中心部視野障害の関係

Relationship between visual acuity and central visual field in late-stage open angle glaucomas

　正常眼圧緑内障（NTG）と原発開放隅角緑内障（POAG）の末期例の中心視力と中心部視野障害の関係を検討した。ハンフリー中心30-2プログラムで得られるmean deviation （MD）が-20dB以下の中間透光体の混濁がない，NTG群33眼（無治療時眼圧21mmHg以下），POAG群71眼（同22mmHg以上）を対象とした。中心視力を0.5以下，0.6〜0.7,0.8〜0.9，および1.0以上に分類し，各群でハンフリー中心10-2プログラム検査で得られた年齢補正正常値との差（total deviation：TD）の平均値を各検査点ごとに求め比較した。中心視力悪化に伴い，中心部視野は，固視点上鼻側，同上耳側および下耳側の順に消失し，最後に下方乳頭黄斑部間視野が消失すると考えられた。視力0.8以上の例では最中心4点のうち，上下にわたる2点以上のTB値が，-10dB以上であることが多く，同条件で0.8以上の視力を予測した場合，特異度92.3％，鋭敏度84.20％であった。

We evaluated 33 eyes of normal-tension glaucoma (NTG) and 71 eyes of primary open angle glaucoma (POAG) in their late stage regarding the relationship between visual acuity and central visual field. As categories for inclusion in the study, all eyes were without media opacities and showed mean deviation (MD) within -20dB obtained by STAPAC of Humphrey Visual Field Analyzer. There were no differences regarding MD, refraction, visual acuity or age between NTG and POAG groups. The eyes were further divided into 4 subgroups according to visual acuity: those with 10/20 or less, between 12/20 and 14/20, 16/20 and 18/20 and 20/20 or better. Each group was tested as to mean of total deviation (TD) and deviation from age-corrected normal reference value for each test point of Program 10-2. Deterioration of central visual acuity was associated by visual field damage in the order of superior temporal, superior nasal, inferior temporal and finally inferior cecocentral area. The majority of eyes with visual acuity of 16/20 or better showed TD values of -10dB or better in test points nearest to the point of fixation.