[1] Univ Penn, Sch Vet Med, Sect Ophthalmol, Philadelphia, PA 19104 USA
[2] Univ Penn, Scheie Eye Inst, Dept Ophthalmol, Perelman Sch Med, Philadelphia, PA 19104 USA
[3] Univ Florida, Dept Mol Genet & Microbiol, Gainesville, FL 32610 USA
[4] Univ Florida, Dept Ophthalmol, Gainesville, FL 32610 USA