パターンERGによる緑内障性早期視神経障害の検出

Detection of early glaucomatous nerve fiber damage by pattern ERG

　正常24眼，視神経および神経線維層に異常を認めない高眼圧症（OH-1群）15眼，C／D比が0.6以上あるいは神経線維層欠損（nerve fiberlayer defect：NFLD）を認めゴールドマン視野に異常を認めない群でピロカルピンを使用していない群（OH-2群）10眼，OH-2群と同程度の乳頭，NFLD，視野であるがピロカルピンを使用している群（OH-3群）6眼，原発開放隅角緑内障で湖崎分類IIa〜IIIa （ピロカルビン使用）の15眼，同程度の視野異常を示す低眼圧緑内障13眼においてパターンERG （PERG）とパターンVECP（PVECP）を同時記録しその潜時について検討した．

　OH-1群は正常群と差を認めないがOH-2群はPEPG潜時が有意に延長しPVECPの変化より鋭敏であった．OH-3群とPOAG群は明らかな潜時の延長を認めた．また個体差のため個々の症例における異常の判定は困難であったが視野変化進行と共に潜時は延長する傾向がある．低眼圧緑内障は同程度の視野変化を示す高眼圧緑内障群に比してPERG潜時の延長が不明瞭であり両者間の病態の差異を示すものと推論した．

We studied pattern electroretinogram (ERG) to evaluate early glaucomatous nerve fiber damage in a total of 73 eyes. The series included 24 normal eyes, 31 eyes with ocular hypertension (OH), 15 eyes with primary open angle glaucoma (POAG) and 13 eyes with low tension glaucoma associated with visual field changes matching those of POAG group. The OH eyes were further subdivided into 3groups : 15 eyes without disc changes nor nerve fiber layer defect (NFLD) (OH-1), 10 eyes with cup -disc ratio (C/D ratio) greater than 0.6 and/or NFLD without field changes nor pilocarpine instil-lation (011-2) and 6 eyes with C/D ratio greater than 0.6 and/or NFLD and pilocarpine instillation without field changes (OH-3).

The latency of pattern ERG in OH-1 was the same with normal group, slightly elongated in OH-2 and was obviously elongated in OH-3 and POAG groups. While there were considerably large varia-tions in the latency for each patient, we noted a tendency for more significant delay in more advanced cases. The changes in pattern ERG were more sensitive than pattern VECP.

The latency in low tension glaucoma was less significant than in high tension glaucoma eyes. This finding was suggestive of different pathogenesis for nerve fiber damage in these two groups.

Rinsho Ganka (Jpn J Clin Ophthalmol) 41(5) : 521-524, 1987