As the eyes contain fewer than 400 visual cells, T. atrica can probably only distinguish light and dark.

Green rods (a special type of visual cell, unknown in caecilians)

Retinal correspondence is the inherent relationship between paired retinal visual cells in the two eyes.

He explains: "Most pitches are released above the shoulder and the hitting motion in the batter is started by the visual cells that 'see' those pitches.

Lin would stand and stare at him, switching focus rapidly from visual cell to cell, her concentration fleeting across her eyes, gauging the aggregate that was Mr. Motley through the minutely changing parts.

The eyes can focus independently, and are specialized with a duplex retina that contains two types of visual cells for both day and night vision, and a tapetum lucidum which reflects onto the retina to enhance vision in the dark.

Several years ago, Dr. Galaburda and a colleague, Dr. Margaret Livingstone, found that the visual cells specialized for fast information processing were abnormal in both the left and right hemispheres, indicating that dyslexia was a visual problem.

The pigmented layer of retina or retinal pigment epithelium (RPE) is the pigmented cell layer just outside the neurosensory retina that nourishes retinal visual cells, and is firmly attached to the underlying choroid and overlying retinal visual cells.