Chapter 12: The Eye

Overview

• Focus on the eye, its structures, functions, and potential problems.
• Eyes are the organs of vision, located in the skull's orbits.
• Only a small portion of the eye is visible externally.

Basic Structures of the Eye

Sclera

• Protective outer layer of the eye.
• Appears as the white part of the eye.

Cornea

• Transparent part of the sclera.
• Allows light to enter the eye.

Choroid

• Middle layer, rich in blood vessels.
• Provides oxygen and nutrients.

Iris

• Pigmented muscle, controls pupil size.
• Regulates light entering the eye.

Pupil

• Central hole regulated by the iris.
• Allows light into the eye.

Lens

• Focuses light onto the retina.
• Incorrect shape can cause vision problems.

Retina

• Innermost layer containing vision receptors.
• Sends visual information to the brain.

Humors

• Aqueous Humor: Located in the anterior cavity, maintains eye shape.
• Vitreous Humor: Jelly-like fluid, supports eye shape.

Other Structures

• Meibomian Glands: Secrete oil, lubricate the eye.
• Lacrimal Glands and Ducts: Tear production and drainage.
• Optic Nerve: Carries visual impulses to the brain.
• Conjunctiva: Mucous membrane lining the eyelid.

Pathway of Light

• Light travels through the cornea, aqueous humor, pupil, lens, vitreous humor, and reaches the retina.
• Optic nerve transmits information to the brain.

Medical Terminology

Combining Forms

• Blephar/o: Eyelid
• Conjunctiv/o: Conjunctiva
• Corne/o, Kerat/o: Cornea
• Dacry/o, Lacrim/o: Tears
• Irid/o, Ir/o: Iris
• Ocul/o, Ophthalm/o: Eye
• Opt/o: Vision
• Phac/o, Phak/o: Lens
• Retin/o: Retina
• Scler/o: Sclera

Conditions

• Amblyopia: Reduced vision, often called lazy eye.
• Astigmatism: Irregular curvature of cornea or lens.
• Cataract: Clouding of the lens.
• Glaucoma: Increased intraocular pressure.

Surgical Terms

• Blepharoplasty: Repair of the eyelid.
• Keratoplasty: Corneal repair or transplant.
• Trabeculectomy: Creates an opening to alleviate intraocular pressure.

Diagnostic Procedures

• Fluorescein Angiography: Images blood vessels in the eye.
• Tonometer: Measures eye pressure.

Complementary Terms

• Terms related to eye structures and conditions.
  • E.g., Binocular, Corneal, Intraocular, Lacrimal

Professions

• Ophthalmologist: Specialist in eye diseases and surgery.
• Optometrist: Measures vision and prescribes corrective lenses.
• Optician: Fills lens prescriptions.

Abbreviations

• Keep track of common abbreviations used in ophthalmology.

Advice: Engage with exercises in the textbook for better understanding and preparation for exams.