乳幼児における視力発達について

Development of visual acuity in infant and young children assessed with preferential looking

　生後2カ月より3歳までの正常乳幼児の視力発達過程をpreferential looking（PL）法をもちいて調べた。生後12カ月未満の乳児にはForced choice preferential looking（FPL）法を，それ以上の年齢の乳幼児には知能，行動の発達に応じて，検査殊に応答法に工夫を加えて検査を施行した。

　その結果PL視力は生後6カ月では15 min of arc，生後12カ月では6min of arc，生後24カ月では3min of arc，そして生後30カ月ではlmin of arcのレベルに達した。

　PL法の成功率は生後3〜6カ月の群および生後25カ月以降の群で高く，生後13〜18カ月の群で最も低い値を示した。

　PL法はやり力を工夫することにより生後2,3歳まで有効に行えることが判った。

The development of visual acuity in normal in-fants and young children from age of 2 months to 3 years was evaluated by preferential looking technique (PL). Those cases younger than 12 months were evaluated by simple forced choice preferential looking method. For those older than 13 months, a modified technique to make them more active in the examination was added.

The PL acuity at the age of 6 months was 15 min, at the age of 12 month it was 6 min. At the age of 18 months 4 min, and 3 min at the age of 24 month. The PL acuity reached to the level of 1.0 min at the age of 30 month.