trans-retinal

all-trans-ret·i·nal

(awl'tranz-ret'i-năl),
The orange retinaldehyde resulting from the action of light on the rhodopsin of the retina, which converts the 11-cis-retinal component of the rhodopsin to all-trans-retinal plus opsin.

trans-retinal

(trăns-rĕt′ĭ-năl)
The form of retinal created when light strikes the retina. It separates from the opsin of the photopigment (rhodopsin in rods), which is then said to be bleached. The enzyme retinal isomerase converts it back to cis-retinal, and the photopigment is again able to respond to light.