1 Parts and Functions of the Eye

Key concepts

Before learning about blindness and low vision, practitioners need to know the basics of the visual system.

Light enters through the cornea, “the window that lets light into the eye” (Green, 2015, 3:35).

Light hits the convex lens that projects it onto the retina. Humans have two types of photoreceptors in the retina, rods and cones, which convert light into electrical signals and generate axon potentials. Rods are more light sensitive and register greyscale and general shape. Cones sit near the center of the retina and allow for detailed color vision. Near the center of the retina is the fovea. It has a thinner surface so that light can penetrate. The fovea is important for high acuity and color vision. The area right around the fovea is the macula. The macula is the area that degenerates in macular degeneration.

Information is then transmitted to the brain through the optic nerve.

Image attribution: Rhcastilhos and Jmarchn, CC BY-SA 3.0, via Wikimedia Commons

Visual system crash course

To learn more, please watch this 10-minute video, which provides an introduction to the visual system (Green, 2015).

References

Green, H. [Crash Course]. (2015, May 11). Vision: Crash course anatomy & physiology #18 [Video]. YouTube. https://youtu.be/o0DYP-u1rNM?si=GOOfo3_s_xVFwh5t