BONY ORBITAL MORPHOLOGY IN NEUROFIBROMATOSIS TYPE-1 (NF1)

We retrospectively compared patients with NF1 with and without optic p athway gliomas (OPG) to determine the incidence and range of orbital d evelopmental abnormalities and compared the incidence of OPG in Africa n-Americans and whites. From cranial MR scans, we manually measured 14 orbital dimensions, compared them to published standards of Waitzman et al, calculated orbital volumes, and determined the presence or abse nce of volumetric symmetry (Delta v) (Delta v less than or equal to 0. 3 cm(3) was considered to be symmetrical). We compared the results of orbital configurational assessment between patients with (group I) and those without OPG (group II). The study population comprised 58 patie nts, 24 boys, 18 African-American, and one Hispanic. Median age at ima ging was 7 years (range 0.5-25.5 years). Fifty-eight percent had confo rmational abnormalities, 16 of whom had more than one abnormality (28% ), the most frequent being increased intertemporal distance (n = 10), increased lateral orbital distance (n = 8), increased medial wall leng th (n = 6), and decreased medial wall length (n = 6). The increased in tertemporal and lateral orbital distances may contribute to the appear ance of hypertelorism. Only two patients had sphenoid wing hypoplasia. We found a high incidence of orbital dimensional abnormalities in the total population but more often saw multiple abnormalities in patient s with OPG. However, no pattern of configurational abnormality emerged . OPG is less frequent in African-Americans. Orbital volumetric dispar ity seems to be independent of the presence of OPG.