Preoperative evaluation of limbal dermoids using high-resolution biomicroscopy

Background: Only a few case reports have described the ultrasound biomicros copic features of limbal dermoids. It remains unclear whether examination b y ultrasound biomicroscopy (UBM) can detect the corneal depth of penetratio n which would improve planning of surgery. Methods: Eight consecutive patie nts [two female, six male, 1-24 years old (median 8.5 years)] examined by U BM (Zeiss-Humphrey, 50 MHz) were retrospectively studied. Five of the dermo ids were excised without corneal grafting and histopathological evaluation was obtained. Results: Seven out of eight dermoids were located in the temp oral lower quadrant. A Goldenhar syndrome was known in three cases. In all cases but one, UBM showed a more reflective and predominantly homogeneous l esion compared with the unaffected corneal stroma, so that the lateral marg ins of the lesion could be clearly identified. Incomplete stromal penetrati on of the dermoid was noticed in four cases; one eye showed a corneal full thickness dermoid. An intraocular protrusion was seen in one eye. Two more cases remained unclear because of reduced compliance. Descemet's membrane b eneath the dermoid could not be visualized in most cases (seven out of eigh t) because of strong sound attenuation inside the lesion. Histopathological evaluation of five cases revealed the typical signs of a limbal dermoid. C onclusion: UBM improves the preoperative evaluation of limbal dermoids. Sub tle examination technique for the depth of corneal penetration is required because of the strong sound attenuation in this tissue, reducing the visibi lity of deep corneal structures.