The Special Senses: The Eyes 7 The Special Senses: The Eyes

Multimedia Directory Slide 25 The Eye Animation Slide 35 Cataract Video Slide 39 Conjunctivitis Video Slide 49 Macular Degeneration Video

Learning Objectives After completing this chapter, you will be able to: Define and spell the word parts used to create medical terms for the eyes Identify the parts of the eyes and describe their structure and function Define common medical terms used for the eyes

Learning Objectives (cont.) After completing this chapter, you will be able to: Break down and define common medical terms used for symptoms, diseases, disorders, procedures, treatments, and devices for the eyes

The Special Senses The special senses provide the brain with information about the outside environment There are four special senses Sight Hearing Taste Smell In this chapter, we will focus on sight

Prefixes a-, an- = without bi-, bin- = two e- = to remove endo- = within hyper- = excessive, abnormally high, above intra- = within para- = near, alongside, departure from normal

Combining Forms angi/o = blood vessel asthen/o = weakness blast/o = germ, bud, developing cell blephar/o = eyelid conjunctiv/o = to bind together, conjunctiva

Combining Forms (cont.) cor/o, core/o = pupil corne/o = horny, cornea cyst/o = bladder, sac dacry/o = tear

Combining Forms (cont.) dipl/o = double emmetr/o = according to measure ir/o, irid/o = rainbow, iris kerat/o = hard, horny tissue lacrim/o = tear

Combining Forms (cont.) leuk/o = white myc/o = fungus nucle/o = kernel nyct/o, nyctal/o = night, nocturnal

Combining Forms (cont.) ocul/o = eye ophthalm/o = eye opt/o = eye, vision phac/o, phak/o = lens phot/o = light presby/o = old age

Combining Forms (cont.) retin/o = net, retina scler/o = thick, hard, sclera son/o = sound stigmat/o = point ton/o = tone, tension, pressure vitr/o, vitre/o = glassy

Suffixes -algia = pain -ation = process -ician = one who treats -metrist = one who measures -metry = measurement -opia = vision

Suffixes (cont.) -phobia = fear -plegia = paralysis (major) -ptosis = falling down, drooping -rrhagia = bleeding, hemorrhage -scopy = process of viewing

Anatomy and Physiology Orbit: Recession in the skull where each eye is set Conjunctiva: A thin layer of cells that covers the eye’s surface and the eyelid’s inner surface

Anatomy and Physiology (cont.) Lacrimal glands and meibomian glands: Provide watery secretions to keep the conjunctiva moist The internal walls of the eye have three layers fibrous layer vascular layer nervous layer

Figure 7.1 Anterior surface of the eye

Figure 7.2 Eye structure

Fibrous Layer The outermost layer of the eye contains: Sclera: White part of the eye Cornea: Transparent window of the eye Anterior chamber: Located behind the cornea and filled with a watery fluid called aqueous humor, which is continually produced and reabsorbed

Vascular Layer The middle layer of the eye includes: Iris: Colored ring of the eye Pupil: Black-appearing opening in the center of the eye Lens: Transparent disk that changes shape to allow light to focus on the retina Posterior cavity behind lens is filled with vitreous humor, a gelatinous material Choroid: Blood vessels here nourish cells of retina

Nervous Layer The innermost layer of the eye consists of: Retina: Thin film at the back of the eye composed of photoreceptors Rods: Black and white shades Cones: Color Fovea centralis Area of the retina that has the sharpest vision Contains highest concentration of cones in the retina

Nervous Layer (cont.) Macula Optic nerve Optic disc Slight depression where fovea centralis lies Optic nerve The neurons that form the retina send information out of the eye by way of the optic nerve Optic disc Exit point of the optic nerve Also called the blind spot

Figure 7.3 Retina

Figure 7.3 (continued) Retina

The eye animation Click on the screenshot to view an animation on anatomy of the eye. The animation may take a moment to begin playing. Back to Directory

Word Roots conjunctiv = to bind together corne = horny, cornea ir = rainbow, iris lacrim = tear ocul = eye opt = eye, vision retin = net, retina scler = thick, hard

Symptoms and Signs Asthenopia Blepharoptosis Emmetropia Eyestrain Drooping eyelid Emmetropia Normal condition of the eye

Figure 7.4 Blepharoptosis Source: Leonard Lessen/Peter Arnold, Inc.

Figure 7.5 Emmetropia and vision problems

Figure 7.5 (continued) Emmetropia and vision problems

Figure 7.5 (continued) Emmetropia and vision problems

Symptoms and Signs (cont.) Leukocoria Condition of white in the pupil Ophthalmalgia Pain associated with the eye Ophthalmorrhagia Hemorrhage of the eye

Diseases and Disorders Astigmatism Defective curvature of the eye’s refractive surface Abbreviated Ast Blepharitis Inflammation of the eyelid

Diseases and Disorders (cont.) Cataract A reduction of the transparency of the lens Chalazion A localized swelling at the edge of an eyelid caused by obstruction of a meibomian gland

Click on the screenshot to view a video on the topic of cataracts. Cataract Movie Click on the screenshot to view a video on the topic of cataracts. Back to Directory

Figure 7.6 Chalazion Source: Custom Medical Stock Photo, Inc

Diseases and Disorders (cont.) Conjunctivitis Inflammation of the conjunctiva Also called pinkeye

Figure 7.7 Conjunctivitis Source: Buddy Crofton/Medical Images, Inc.

Conjunctivitis Movie Click on the screenshot to view a video on the topic of conjunctivitis. Back to Directory

Diseases and Disorders (cont.) Dacryocystitis Inflammation of the lacrimal sac Detached retina Separation of the retina from the choroid at the back of the eye

Diseases and Disorders (cont.) Diplopia Double vision Endophthalmitis Inflammation of internal tissues of the eye

Diseases and Disorders (cont.) Glaucoma Results from increased intraocular pressure, which damages the optic nerve Hordeolum An infection of a meibomian gland, which causes a local swelling of the eyelid Also called sty

Figure 7.8a Glaucoma

Figure 7.8b (continued) Glaucoma

Figure 7.8c (continued) Glaucoma Courtesy of the National Eye Institute: National Institute of Health.

Figure 7.9 Hordeolum Source: Science Photo Library/Photo Researchers, Inc.

Diseases and Disorders (cont.) Hyperopia Reduced vision of nearby objects Also called farsightedness Iridoplegia Paralysis of the iris Iritis Inflammation of the iris

Diseases and Disorders (cont.) Keratitis Inflammation of the cornea Macular degeneration Progressive deterioration of an area of the retina known as the macula lutea, which leads to a loss of central vision Most common cause is age, therefore it is called age-related macular degeneration

Macular Degeneration Video Click on the screenshot to view a video on the topic of macular degeneration. The video may take a moment to begin playing. Back to Directory

Diseases and Disorders (cont.) Myopia Reduced vision of distant objects Also called nearsightedness Nyctalopia Poor vision at night or in dim light

Diseases and Disorders (cont.) Nystagmus Involuntary, rhythmic movements of the eye Oculomycosis Fungal infection of the eye Ophthalmopathy A general term for a disease of the eye

Diseases and Disorders (cont.) Ophthalmoplegia Paralysis of the eye that affects the muscles moving the eyeball Photophobia Caused by irritation of either the optic nerve, or certain eye structures

Diseases and Disorders (cont.) Photoretinitis Inflammation of the retina caused by extreme light intensity Presbyopia Hyperopia due to aging Pterygium Abnormal fold of fibrous tissue that extends between the conjunctiva and cornea

Diseases and Disorders (cont.) Retinitis pigmentosa An inherited disease characterized by night blindness progressive atrophy retinal pigment changes Retinoblastoma A malignant tumor that originates from a developing retinal cell

Diseases and Disorders (cont.) Retinopathy A general term for any disease of the retina Sclerokeratitis Inflammation of the sclera and cornea Scleromalacia Softening of the sclera Scotoma An abnormal blind spot in vision

Figure 7.10 Retinopathy

Diseases and Disorders (cont.) Strabismus A condition of crossed eyes heterotropia if both eyes deviate inward or outward esotropia if one eye deviates inward exotropia if one eye deviates outward

Figure 7.11 Strabismus Source: Barts Medical Library/Phototake NYC.

Treatments, Procedures, and Devices Blepharoplasty Surgical repair of an eyelid Cataract extraction Surgical excision of a lens that has lost its clarity

Figure 7.12 Cataract extraction

Figure 7.12 (continued) Cataract extraction

Figure 7.12 (continued) Cataract extraction

Treatments, Procedures, and Devices (cont.) Distance visual acuity A test of the ability to see the details and shape of objects from recorded distances Enucleation Excision of an eyeball from the socket

Treatments, Procedures, and Devices (cont.) Fluorescein angiography Visual recording of blood vessels in the retina and choroid using fluorescein dye, which is injected into a vein and circulates through the eye Intraocular lens transplant Surgical implantation of an artificial lens to replace a defective natural lens

Treatments, Procedures, and Devices (cont.) Iridectomy Surgical excision of a portion of the iris Iridotomy Incision into the iris to allow the aqueous humor to drain from the anterior chamber Usually performed with a laser to treat glaucoma

Treatments, Procedures, and Devices (cont.) Keratometry A procedure using a handheld device called a keratometer, which measures the curvature of the cornea Usually used for fitting contact lenses Keratoplasty Corneal transplant

Treatments, Procedures, and Devices (cont.) LASIK Acronym for laser-assisted in situ keratomileusis; use of a laser to correct vision abnormalities, such as myopia, hyperopia, and astigmatism Ophthalmic evaluation A variety of procedures using specialized instruments to assist in the diagnosis of eye disorders

Treatments, Procedures, and Devices (cont.) Ophthalmologist A physician who specializes in the treatment of eyes Ophthalmology Study of disease related to the eyes

Treatments, Procedures, and Devices (cont.) Ophthalmoscopy Use of a handheld instrument with a light, called an ophthalmoscope, to view the eye’s interior Optician A technician trained in filling prescriptions for corrective lenses Optometrist A professional trained to examine eyes

Figure 7.13 Ophthalmoscopy Source: Pearson Education

Treatments, Procedures, and Devices (cont.) Optometry Measurement of vision, usually to test acuity for prescribing corrective lenses Uses optometer to measure the range and sharpness of vision

Figure 7.14 Optometry Source: David Weintraub/Photo Researchers, Inc.

Treatments, Procedures, and Devices (cont.) Phacoemulsification Use of ultrasound frequencies to break up a cataract, which is then aspirated and removed Photorefractive keratectomy Use of a laser to reshape the cornea in an effort to correct myopia Abbreviated PRK

Treatments, Procedures, and Devices (cont.) Radial keratotomy Incisions into the cornea to produce a spoke-like effect, which serves to flatten the cornea and correct for myopia Abbreviated RK Scleral buckling Repair of a detached retina

Treatments, Procedures, and Devices (cont.) Sonography High-frequency sound waves used to detect problems associated with the eye, such as foreign objects, detached retina, etc. Strabotomy Incision into the tendon of an eye’s extrinsic muscle to correct strabismus

Treatments, Procedures, and Devices (cont.) Tonometry Measurement of intraocular pressure, primarily used to test for glaucoma An instrument called a tonometer is used Vitrectomy Surgical removal of the vitreous humor

Pharmaceuticals Anesthetic ophthalmic solutions Antibiotic ophthalmic ointment Antiglaucomas Miotics Mydriatics

Abbreviations ARMD Ast Em EENT LASIK OD

Abbreviations (cont.) OS OU PRK RK VA

Classroom Response System Pretest

What combining form means to bind together? conjunctiv/o corne/o dipl/o kerat/o

What combining form means to bind together? conjunctiv/o corne/o dipl/o kerat/o

What combining form means old age? vitr/o stigmat/o dacry/o presby/o

What combining form means old age? vitr/o stigmat/o dacry/o presby/o

What suffix means excessive discharge of fluid? -rrhagia -plegia -algia -rrhea

What suffix means excessive discharge of fluid? -rrhagia -plegia -algia -rrhea

What part of the eye contains photoreceptors? lens retina cornea sclera

What part of the eye contains photoreceptors? lens retina cornea sclera

What part of the eye consists of smooth muscle? iris retina cornea sclera

What part of the eye consists of smooth muscle? iris retina cornea sclera

What structure is the origin of tears? lacrimal gland meibomian gland cornea conjunctiva

What structure is the origin of tears? lacrimal gland meibomian gland cornea conjunctiva

Classroom Response System Post-test

What term refers to inflammation of the eyelids? dacryocystitis conjunctivitis blepharoptosis blepharitis

What term refers to inflammation of the eyelids? dacryocystitis conjunctivitis blepharoptosis blepharitis

What term is known as a condition of double vision? diplopia glaucoma conjunctivitis cataract

What term is known as a condition of double vision? diplopia glaucoma conjunctivitis cataract

What is another term for sty? glaucoma dacryolithiasis hordeolum conjunctivitis

What is another term for sty? glaucoma dacryolithiasis hordeolum conjunctivitis

What is the term for reduction in vision due to age? presbyopia myopia hyperopia emmetropia

What is the term for reduction in vision due to age? presbyopia myopia hyperopia emmetropia

What is the general term for a disease of the eye? retinopathy nystagmus ophthalmopathy scleropathy

What is the general term for a disease of the eye? retinopathy nystagmus ophthalmopathy scleropathy

The procedure during which a portion of the iris is removed is: enucleation iridectomy iridotomy keratometry

The procedure during which a portion of the iris is removed is: enucleation iridectomy iridotomy keratometry

The use of a laser to flatten the corneal surface to correct myopia is abbreviated as: PRK RK LASIK VA

The use of a laser to flatten the corneal surface to correct myopia is abbreviated as: PRK RK LASIK VA