[1] WILLS EYE HOSP, ONCOL SERV, PHILADELPHIA, PA 19107 USA
[2] CHILDRENS HOSP, DEPT NEUROPATHOL, PHILADELPHIA, PA 19104 USA
[3] MCGILL UNIV, DEPT OPHTHALMOL, MONTREAL H3A 2T5, QUEBEC, CANADA
[4] MCGILL UNIV, DEPT PATHOL, MONTREAL H3A 2T5, QUEBEC, CANADA