Purpose Posterior amorphous corneal dysgenesis is a rare disorder previously described in only four families. We expanded the spectrum of findings and updated the classification by adding seven additional cases. Methods Three index cases were identified during ophthalmic examination at the El Maghraby Eye Hospital and Eye Center in Jeddah, Saudi Arabia. We examined all available members of three families of different ethnic origin (Saudi Arabian, Egyptian, and Indian) and found seven cases of affected patients. Videokeratography and slit-lamp photomicrography were done in selected cases. Results In all seven cases, the corneas showed bilateral, diffuse, sheetlike opacities in the posterior stroma, with extension to the corneoscleral limbus, and corneal thinning in the more severely affected eyes. The clinical findings included variations in corneal thickness noted by slit-lamp microscopy and ultrasonic pachymetry, cornea plana, marked corneal astigmatism, and progressive ectasia of the cornea. Conclusions Posterior amorphous corneal dysgenesis is characterized by gray sheetlike opacities in the posterior stroma. It occurs in many ethnic groups and exhibits a varied spectrum of clinical findings, including iridocorneal adhesions and cornea plana. We think the anatomic abnormalities of the cornea warrant classification as a corneal dysgenesis rather than as a dystrophy. Longitudinal studies of individual eyes and investigation of associated abnormalities in other pedigrees may help resolve this distinction.