Anatomy Flashcards - Eye Test Chapter 8

Visual Acuity

• Perfect vision is represented by 20/20 on the Snellen Eye chart, but better vision, like 20/15, is possible.

Astigmatism

• Caused by irregular lens shape, leading to scattered light and blurry images.

Blind Spot

• Important to be aware of during activities like driving and contact sports.

Color Vision

• Color perception deficiencies are often genetic and linked to the X chromosome.
• A color-blind male and color-blind female will have a color-blind daughter.

Rods and Cones

• Rods are responsible for dim light vision, while cones detect colors, being classified into red, green, and blue cones.

Accommodation

• The lens changes shape to focus, aided by the ciliary muscles which move the lens for focusing.

Near Point

• As age increases, the near point—the closest focus distance—also increases due to lens deterioration.

Importance of Near Point

• Relevant during tasks such as computer work and sports activities.

Peripheral Vision

• Heavily relied upon in situations like driving, basketball, teaching, and lifeguarding.

Depth Perception

• Poor depth perception can lead to hazards in driving, affecting distance judgment.

Fatty Tissue

• Acts as a cushion for the eye, located around it for protection.

Eye Muscles

• Superior rectus elevates and turns the eye medially; inferior rectus depresses and turns it medially; lateral rectus moves it laterally; medial rectus moves it medially; superior oblique depresses and turns it laterally; and inferior oblique elevates and turns it laterally.

Sclera

• White protective outer layer that extends from the cornea to the optic nerve.

Optic Nerve

• Transmits visual information from the eye to the brain.

Cornea

• Clear outer layer that allows light to enter the eye.

Aqueous Humor

• Maintains intraocular pressure, located between the lens and cornea.

Pupil and Iris

• The pupil, situated at the center of the iris, allows light entry; the iris regulates light levels entering the eye.

Lens

• Focuses light onto the retina and is located behind the iris.

Ciliary Muscles

• Connect the lens to the ciliary body and assist in lens shape alteration.

Vitreous Humor

• Maintains the eye's shape, located behind the lens and in front of the retina.

Retina

• Contains rods and cones, line the inner surface of the eye for light sensitivity.

Blind Spot

• The area where the optic nerve exits, lacking photoreceptors.

Rods and Cones

• Rods facilitate dim light vision, while cones allow for color vision, predominantly found in the fovea centralis.

Tapetum Lucidum

• Enables night vision by reflecting light, found behind the retina in some animals.

Choroid Layer

• Prevents light scattering, located between the sclera and retina, containing blood vessels.

Fovea Centralis

• Point of sharpest vision, containing a high density of cones.

Lacrimal Apparatus

• Protects, moistens, and lubricates the eye; drains into the nasal cavity.

Lacrimal Secretion

• Composed of dilute salt solutions, mucus, antibodies, and lysozyme.

Lysozyme

• An enzyme that combats bacterial infection.

Eye Layers

• The fibrous layer protects the eye, the vascular layer contains blood vessels, and the sensory layer includes receptors for visual transmission.

Common Vision Conditions

• Atrimatrism: uneven curvature of cornea/lens; Emmetropia: normal vision focusing; Myopia: nearsightedness; Hyperopia: farsightedness; Presbyopia: age-related farsightedness; Night blindness: impaired rod function; Color blindness: genetic inability to perceive certain colors; Cataracts: clouded lens; Glaucoma: blocked aqueous humor drainage that raises intraocular pressure.

Reflexes

• Photopupillary reflex: pupils constrict in bright light; accommodation pupillary reflex: pupils constrict when focusing on nearby objects.

Convergence

• A depth perception cue based on the inward angle of the eyes when focusing on close objects.