A Case of Congenital Cornea Plana

This abnormality was first described by Rübel in 1912. It is very rare and in view of the vexed question as to whether it is hereditary or purely spontaneous it seems justifiable to report a new case. This involves a young man of twenty-one, the eldest of six children; his father had died. When he was six he was operated on bilaterally for alternating convergent squint and from childhood on had worn strong convex glasses. At first it seemed as though it was a case of microcornea; the strikingly small, almost oval clear parts of the corneae made the most impression. On closer examination, however, the exceptional flattening of the corneae and of the whole anterior segment of the eyeballs sprang to light. The corneal limbus was flattened out and had progressed irregularly centrally, gradually changing into scleral tissue without having a limbal sulcus. At the same time the slitlamp revealed an extremely shallow anterior chamber and the distinct masking of the chamber angle by milkilyopaque conical tissue that in its deeper layers first cleared up centrally and subsequently changed gradually into a transparent corneal stroma, and more centrally an embryotoxon. The rest of the cornea was thin but completely clear. The extended limbal zones revealed extensive superficial vascularisation which was clearly visible, especially on the upper sides of the corneae. The anterior layers of the irises showed slight atrophy and in R.E. the margins of the pupils were partially blurred; there were also filamentary anterior syn-echiae. No abnormalities were observed on the lenses, the retinae or the optic disks. Visual acuity R. E. with Sph + 7 C + 1 axis 170°: 0.5. Visual acuity L. E. with Sph + 4.5 C + 3 axis 55°: 0.6. Corneal diameter R. E.: 9.5 horizontally and vertically (including the blurred marginal zone). Corneal diameter L. E.: 11 mm. Corneal radius R. E.: at 130°: 10.5 mm, i.e., 32.5 D refraction. Corneal radius L. E.: at 40°: > 11 mm, i.e., < 30 D refraction. All the signs of an uncomplicated congenital cornea plana were present. As far as stronger corneal refraction, respectively a smaller radius and smaller diameter are concerned, border-line cases have 142 Henry, A Case of Congenital Cornea Plana been described and Fríede uses the term pseudo-microcornea. He also presents the following differences between cornea plana and microcornea. Cornea plana Microcornea Abnormal flattening. 1. Normal corneal curvature.