Bloomfield S E, Jakobiec F A, Iwamoto T, Harrison W G
Ophthalmology. 1981 Dec;88(12):1274-80. doi: 10.1016/s0161-6420(81)34878-7.
A 40-year-old black man had two penetrating keratoplasties as a result of complications from alkali burns sustained many years earlier. Two further penetrating keratoplasties were performed for recurrent retrocorneal pigmentation. Both scanning and transmission electron microscopy demonstrated that the retrocorneal pigmented cells were iris melanocytes, based upon their fusiform or dendritic shapes and measurements of their cytoplasmic melanin granules. Repopulation of Descemet's membrane by the melanocytes was produced by a small remnant of atrophic iris. The pigment granules in the iris melanocytes were somewhat larger than those seen in similar cells from Caucasians or Orientals, but had identical measurements to those studied in an iridectomy specimen from another black patient. The retrocorneal iris melanocytes were able to synthesize banded basement membrane material, interrupted laminar basement membrane, and collagen fibrils. The cause of the exfoliation of the iris melanocytes onto the back of the cornea is unknown, but the discovery that iris melanocytes can proliferate in an ongoing fashion and secrete extracellular matrix provides new insight into the physiology of these cells.
一名40岁的黑人男性因多年前碱烧伤并发症接受了两次穿透性角膜移植手术。又因复发性角膜后色素沉着进行了两次穿透性角膜移植手术。扫描电子显微镜和透射电子显微镜均显示，角膜后色素沉着细胞为虹膜黑素细胞，依据其梭形或树突状形态以及对其胞质黑素颗粒的测量结果判断。萎缩虹膜的一小部分残余导致黑素细胞重新在Descemet膜上生长。虹膜黑素细胞中的色素颗粒比白种人或东方人同类细胞中的色素颗粒稍大，但与另一名黑人患者虹膜切除术标本中研究的色素颗粒大小相同。角膜后虹膜黑素细胞能够合成带状基底膜物质、间断层状基底膜和胶原纤维。虹膜黑素细胞脱落在角膜后部的原因尚不清楚，但虹膜黑素细胞能够持续增殖并分泌细胞外基质这一发现为这些细胞的生理学提供了新的见解。
