水晶体欠損症の親子発生例

Coloboma of the crystalline lens in father and daughter

　親子に認められた水晶体欠損症を報告した．発端者は7歳女性で，両眼の水晶体下方に欠損があり，右眼の欠損は左眼より大であった．36歳の父親には，右眼の下方に水晶体欠損を認め，左眼水晶体には異常を認めなかった．両者の類似性から，水晶体欠損症の発生には遺伝因子が関与すると考えられた．発端者を3年5カ月間観察し，右弱視を健眼遮蔽にて良好な矯正視力を得ることができたが，この間に乱視度数（水晶体乱視）の変化はみられなかった．しかし，近視度数の急速な進行がみられ，これは，成長に伴う過度な眼軸の延長によるものと考えられた．若年者で，他に器質的病変を持たない水晶体欠損症をみた場合は，長期間の視力経過を追う必要があると思われる．

A 7-year-old female child noted visual problems of one year's duration in her right eye. Under mydriasis, we found coloboma in the inferior por-tion of the lens bilaterally. The coloboma was larger in the right eye than the left. The corrected visual acuity was 0.3 right, 1.0 left. Her father, 36 years in age, manifested unilateral coloboma in the inferior portion of the lens. In both cases, the zonules were sparse in the colobomatous region.

During the ensuing 40 months, the visual acuity inthe right eye of the child improved to 1.0 due to training and veiling of her left eye. Concomitantly, the myopia in the right eye showed further progres-sion with the astigmatism remaining stable.This change in refraction was thought to be due to elongation of the eyeglobe during this period. These findings indicate that the attending oph-thalmologist has to keep in mind the possibility of visual axial changes as well as visual acuity in cases of coloboma of the lens, particularly in younger subjects.

Rinsho Ganka (Jpn J Clin Ophthalmol) 41(9) : 1085-1088, 1987