Richard W. Darrell

Fibrous Histiocytoma of the Corneoscleral Limbus

A case of epibulbar fibrous histiocytoma is presented, with emphasis on the electron microscopic aspects due to the paucity of ultrastructural descriptions of this rare tumor. A tan-yellow conjunctival tumor developed at the corneoscleral limbus in a 31-year-old male. The clinical diagnosis was confirmed by routine histopathologic evaluation, which demonstrated a typical matted or storiform cellular pattern. Electron microscopy revealed a mixed cell population, composed primarily of histiocytic and fibroblastic cells. The histiocytic cells contained lysosomes and phagosomes and had interdigitating cell processes. The fibroblastic cells were characterized by prominent rough-surfaced endoplasmic reticulum and variable amounts of lipid within vacuoles, but did not possess lysosomes or phagosomes. Both cells occasionally contained an unusual curvilinear structure, suggesting a shared histogenesis. This distinctive inclusion appeared to be a modification of the rough-surfaced endoplasmic reticulum. The nature and origin of the tumor cells are discussed on the basis of their ultrastructure.

CORNEAL TATTOOING TO TREAT GLARE SYMPTOMS FOLLOWING RADIAL KERATOTOMY

Radial keratotomy (RK) may be complicated by postoperative glare and night vision may be compromised when parts of RK incisions fall within the boundary of the dilated pupil. Surgical pigmentation of the cornea has been used to treat glare symptoms caused by corneal trauma and iris loss. In this study, corneal tattooing was performed in a patient who had undergone 16-incision RK and 6-incision astigmatic keratotomy (AK) elsewhere. With one eye covered, the patient in this study was shown a white spot projected onto a visual acuity screen and asked to draw the image on a Night Vision Recording chart before and after tattooing. Sterile iron oxide powder was suspended in sterile saline to approximate the patient’s iris color. Using a 69 Beaver blade, Sinskey hook, and 30-gauge needle, the wounds were reopened and pigment deposited. The procedure was repeated twice. The patient studied reported marked decrease in glare symptoms following tattooing. Postoperative drawings of the projected spot image showed significant regression of halation. Focal areas of pigment dispersion required retreatment, which improved symptoms to a lesser degree. From this result it is concluded that tattooing procedures can be used to pigment radial keratotomy scars in patients who complain of glare. The material best suited for this purpose has yet to be determined. Iron oxide suspensions have been successful, though pigment migration out of the scars seems to have contributed to recurrence of symptoms.