Heterotopic smooth muscle in the choroid of two patients with cryptophthalmos
J. Pe'er and D. BenEzra
The mode of inheritance in the complete cryptophthalmic syndrome is not
clear in all cases. In two of our patients with complete cryptophthalmos,
one showed a probable autosomal-recessive inheritance, while in the other
patient, the mode of transmission could not be determined. Light and
electron microscopic studies of the globes demonstrated heterotopic
smooth-muscle tissue in the anterior part of the choroid in these two
patients. Although these findings might be explained on the basis of a lack
of directional growth of the embryonic ciliary muscle cells during the
early embryonic period, we favor a simple anatomical explanation based on
differentiation arrest of the anterior segment. During the fourth month of
gestation, the growing optic cup presumably fails to advance forward
normally and to differentiate. The relatively normally developing posterior
segment extends posteriorly. The "stretching" backward of the ora serrata
during the seventh month of gestation "drags" with it the ciliary smooth
muscle that did not advance forward due to the earlier arrest. Thus, in the
definite cryptophthalmic eye, the smooth-muscle tissue is localized within
the anterior choroid.
