Iris transillumination requires an undilated pupil and is created by making an axial light beam shine into the small pupil and reflect off the retina. The beam aperture should match the pupil size or be smaller than the pupil to avoid iris reflections.

What is iris transillumination defects?

Definition. Transmission of light through the iris as visualized upon slit lamp examination or infrared iris transillumination videography. The light passes through defects in the pigmentation of the iris. [

What causes iris transillumination defects?

Known causes of acquired iris atrophy with or without transillumination of the iris include herpetic iridocyclitis, pigment dispersion syndrome (PDS), pseudoexfoliation syndrome, Fuchs uveitis syndrome, Vogt-Koyanagi-Harada disease, trauma, and acute angle-closure glaucoma.