External eyes were photographed under a LED blue penlight (467 nm; LDP LLC, Carlstadt, NJ) source, excitation band-pass filter (315–540 nm, 80% transmittance; Beseler, Stroudsburg, PA), emission yellow gel filter 312 (460 nm cutoff <0.1% transmittance; 467 nm, 0.26% transmittance; 505 nm to 525 nm, >80% transmittance in the range of the fluorophore; Rosco Laboratories, Inc., Stamford, CT), and a 9× slit-lamp eyepiece (Leitz, Wetzlar, Germany). Manual camera settings for digital photography were ISO 400, 1/4,” F2.9, VR, no flash, fine 13 m (Coolpix P6000; Nikon, Tokyo, Japan).