38.1 Introduction to the Eyes
2 min read•june 18, 2024
The eye is a complex organ with several key structures working together to enable vision. From the and regulating light entry to the converting light into electrical signals, each part plays a crucial role in visual processing.
Common eye disorders like and can significantly impact vision and eye health. Understanding their causes, symptoms, and proper medication administration techniques is essential for effective treatment and management of these conditions.
Anatomy and Physiology of the Eye
Pupil, iris, retina
Top images from around the web for Pupil, iris, retina
Pupillary light reflex - wikidoc View original
Is this image relevant?
Vision | Anatomy and Physiology I View original
Is this image relevant?
Anatomy of the Eye | Biology for Majors II View original
Is this image relevant?
Pupillary light reflex - wikidoc View original
Is this image relevant?
Vision | Anatomy and Physiology I View original
Is this image relevant?
1 of 3
Top images from around the web for Pupil, iris, retina
Pupillary light reflex - wikidoc View original
Is this image relevant?
Vision | Anatomy and Physiology I View original
Is this image relevant?
Anatomy of the Eye | Biology for Majors II View original
Is this image relevant?
Pupillary light reflex - wikidoc View original
Is this image relevant?
Vision | Anatomy and Physiology I View original
Is this image relevant?
1 of 3
- Pupil allows light to enter the eye, size controlled by iris muscles
- Iris is colored part surrounding pupil, contains muscles regulating light entering eye
- Retina is light-sensitive layer at back of eye, contains photoreceptor cells ( for low-light and peripheral vision, for color vision and visual acuity) converting light into electrical signals
- is clear, protective outer layer helping focus light
- is transparent structure behind iris focusing light onto retina
- carries electrical signals from retina to brain for visual processing
Common Eye Disorders
Glaucoma, conjunctivitis causes and symptoms
- Glaucoma caused by increased due to impaired drainage of , risk factors include age, family history, and certain medical conditions
- Symptoms are gradual loss of peripheral vision, tunnel vision in advanced stages, pain and redness in acute angle-closure glaucoma
- Conjunctivitis (pink eye) caused by viral or bacterial infection, allergies or irritants
- Symptoms are redness and swelling of (white part of eye), itching, burning, or gritty sensation in eye, discharge (watery, mucus, or pus)
Medication Administration Techniques
Eye drops, ointments proper techniques
- Eye drops
- Wash hands thoroughly before administration
- Tilt patient's head back and have them look up
- Gently pull down lower eyelid creating a pocket
- Hold dropper close to eye without touching surface
- Instill prescribed number of drops into pocket
- Have patient close eye and apply gentle pressure on inner corner preventing systemic absorption
- Eye ointments
- Wash hands thoroughly before administration
- Tilt patient's head back and have them look up
- Gently pull down lower eyelid creating a pocket
- Apply thin strip of ointment (about 1 cm) along inside of lower eyelid
- Have patient close eye and gently massage eyelid distributing ointment evenly
- General tips
- Use separate tube or dropper for each eye preventing cross-contamination
- Wait at least 5 minutes between administering different eye medications
- Educate patient on proper storage and handling of eye medications
Key Terms to Review (73)
Accommodation: Accommodation is the process by which the eye changes its focus from distant to near objects, involving the adjustment of the lens shape. This is essential for clear vision across different distances.
Acetazolamide: Acetazolamide is a carbonic anhydrase inhibitor that is primarily used as an antiglaucoma medication. It works by reducing the production of aqueous humor in the eye, which helps to lower intraocular pressure and manage glaucoma symptoms.
Acute angle-closure (narrow-angle) glaucoma: Acute angle-closure (narrow-angle) glaucoma is a type of glaucoma where the iris blocks the drainage angle in the eye, leading to a rapid increase in intraocular pressure. This condition is an ocular emergency requiring immediate treatment to prevent vision loss.
Alpha-2 Agonists: Alpha-2 agonists are a class of drugs that act on the alpha-2 adrenergic receptors in the body, primarily in the central nervous system. These receptors play a key role in the regulation of various physiological processes, including intraocular pressure, which is the focus of this discussion in the context of the 38.1 Introduction to the Eyes topic.
American Academy of Ophthalmology: The American Academy of Ophthalmology (AAO) is a professional medical association for ophthalmologists in the United States. It focuses on advancing the lifelong learning and professional interests of ophthalmologists to ensure the highest quality eye care.
Anxiety: Anxiety is a state of excessive worry and fear that can interfere with daily activities. It is commonly treated with anxiolytics, which are medications designed to reduce anxiety symptoms.
Aqueous humor: Aqueous humor is a transparent fluid produced in the eye's ciliary body that fills the anterior and posterior chambers. It helps maintain intraocular pressure, provides nutrients, and removes waste from the eye.
Aqueous Humor: Aqueous humor is a clear, watery fluid that fills the space between the cornea and the lens of the eye. It plays a crucial role in maintaining the shape and pressure of the eye, as well as providing nourishment to the surrounding tissues.
Asian clients: Asian clients in pharmacology refer to individuals of Asian descent who may exhibit unique responses to medications due to genetic, cultural, and physiological factors. Understanding these differences is crucial for personalized and effective treatment.
Astigmatism: Astigmatism is a common refractive error in the eye where the cornea or lens has an irregular shape, leading to blurred or distorted vision. It can affect both near and far vision and often occurs alongside myopia or hyperopia.
Beta-Blockers: Beta-blockers are a class of medications that work by blocking the effects of the hormone epinephrine (adrenaline) on the body. They are primarily used to treat various cardiovascular conditions, such as hypertension, angina, and heart failure, by reducing the heart's workload and oxygen demand.
Black: Black is a term often used to describe the absence of color or light. In medical contexts, it can refer to certain labels or warnings related to drug safety and adverse effects.
Canaloplasty: Canaloplasty is a surgical procedure performed to treat glaucoma by improving the drainage of aqueous humor from the eye. It involves inserting a microcatheter into Schlemm's canal to widen it and facilitate fluid outflow.
Carbonic Anhydrase Inhibitors: Carbonic anhydrase inhibitors are a class of drugs that work by blocking the activity of the enzyme carbonic anhydrase, which is involved in the regulation of fluid balance and pH levels in the body. These inhibitors have applications in the treatment of Alzheimer's disease as well as certain eye conditions.
Carbonic Anhydrase Inhibitors (CAIs): Carbonic Anhydrase Inhibitors (CAIs) are a class of drugs that reduce the activity of the enzyme carbonic anhydrase. They are often used to treat conditions like glaucoma, epilepsy, and certain types of edema.
Cataracts: Cataracts are a clouding of the eye's natural lens, leading to decreased vision. They are often age-related and can significantly impair daily activities if untreated.
Cataracts: Cataracts are a clouding of the normally clear lens of the eye, which can lead to vision impairment and eventual blindness if left untreated. This condition is commonly associated with aging, but can also occur due to various other factors.
Chalazion: A chalazion is a painless, localized swelling of the eyelid caused by a blocked meibomian gland. It can sometimes become inflamed or infected, requiring medical intervention.
Choroid: The choroid is a layer of the eye that lies between the sclera and the retina. It is a highly vascular layer that provides nourishment and oxygen to the outer layers of the retina, playing a crucial role in the visual process.
Closed-angle glaucoma: Closed-angle glaucoma is a type of glaucoma where the drainage angle between the iris and cornea becomes blocked, leading to increased intraocular pressure. This condition can cause sudden vision loss and requires immediate medical attention.
Closed-angle Glaucoma: Closed-angle glaucoma is a type of glaucoma characterized by a sudden increase in intraocular pressure due to a blockage in the drainage of aqueous humor from the eye. This can lead to optic nerve damage and vision loss if left untreated.
Cones: Cones are photoreceptor cells in the retina responsible for color vision. They function best in bright light conditions and are essential for visual acuity.
Conjunctiva: The conjunctiva is a thin, transparent membrane that covers the front of the eye and the inner surface of the eyelids. It plays a crucial role in the overall health and function of the eye, particularly in the context of ocular anti-inflammatories, anti-infectives, anesthetics, and lubricants.
Conjunctivitis: Conjunctivitis, commonly known as pink eye, is an inflammation or infection of the conjunctiva, the transparent membrane that lines the eyelid and covers the white part of the eyeball. It can be caused by bacteria, viruses, allergens, or irritants.
Cornea: The cornea is the clear, curved, outermost layer of the eye that acts as the primary refracting surface, focusing light onto the retina. It plays a crucial role in vision by refracting and transmitting light into the eye, protecting the internal structures, and providing a smooth, transparent surface for light to enter the eye.
Cyclosporine: Cyclosporine is an immunosuppressant drug primarily used to prevent organ rejection in transplant patients and to treat various autoimmune disorders. It works by inhibiting the activation and proliferation of T-cells, a critical component of the body's immune response.
Dacryoadenitis: Dacryoadenitis is the inflammation of the lacrimal gland, which produces tears. It can be acute or chronic and may result from infections, autoimmune diseases, or other causes.
Dacryocystitis: Dacryocystitis is an infection and inflammation of the lacrimal sac, usually due to an obstruction in the nasolacrimal duct. It can lead to pain, redness, and swelling around the inner corner of the eye.
Diabetic Retinopathy: Diabetic retinopathy is a complication of diabetes that occurs when high blood sugar levels damage the blood vessels in the retina, the light-sensitive tissue at the back of the eye. This damage can lead to vision impairment and blindness if left untreated.
Dry Eye Syndrome: Dry eye syndrome is a chronic condition characterized by inadequate tear production or excessive tear evaporation, leading to eye discomfort, inflammation, and potential vision problems. It is a common ocular condition that can significantly impact a person's quality of life.
Dry macular degeneration (DMD): Dry macular degeneration (DMD) is a common eye disorder among people over 50, characterized by the thinning of the macula, leading to vision loss. It progresses slowly and is the most common form of macular degeneration.
Episcleritis: Episcleritis is an inflammation of the episclera, a thin layer of tissue between the conjunctiva and the sclera. It often presents as mild eye redness and irritation.
External ocular structures: External ocular structures are the parts of the eye that are visible externally, including the eyelids, eyelashes, conjunctiva, and cornea. They play crucial roles in protecting the eye and maintaining vision.
Glaucoma: Glaucoma is a group of eye conditions that can damage the optic nerve, often due to increased pressure within the eye. It is a leading cause of irreversible blindness worldwide and can affect various aspects of the nervous system, eyes, and fluid regulation in the body.
Hispanic: Hispanic refers to people, cultures, or countries related to Spain or Spanish-speaking countries in Latin America. It is an ethnic category that encompasses a diverse range of backgrounds.
Hordeolum: A hordeolum, commonly known as a stye, is an acute infection of the oil glands in the eyelid, usually caused by Staphylococcus bacteria. It presents as a red, painful lump near the edge of the eyelid.
Hyperopia: Hyperopia, also known as farsightedness, is a common refractive error where distant objects are seen more clearly than near ones. It occurs when the eyeball is too short or the cornea has too little curvature.
Internal ocular structures: Internal ocular structures are the anatomical components within the eye, including the lens, retina, optic nerve, and vitreous humor. These structures play critical roles in vision by focusing light and transmitting visual signals to the brain.
Intraocular Pressure: Intraocular pressure (IOP) refers to the fluid pressure within the eyeball. It is a critical factor in the health and function of the eye, as it helps maintain the eye's shape and protects the delicate structures within. This term is particularly relevant in the context of topics such as osmotic diuretics, ocular anti-inflammatories and anti-infectives, and antiglaucoma drugs, as they all play a role in regulating or managing intraocular pressure.
Intraocular pressure (IOP): Intraocular pressure (IOP) is the fluid pressure inside the eye. It is an important measure in assessing and managing conditions like glaucoma.
Iridectomy: An iridectomy is a surgical procedure in which a small portion of the iris, the colored part of the eye, is removed. This procedure is typically performed to treat various eye conditions, such as glaucoma, by creating an opening in the iris to improve the flow of fluid and reduce intraocular pressure.
Iridotomy: An iridotomy is a surgical procedure that creates a small opening in the iris, the colored part of the eye, to help relieve pressure buildup within the eye. This procedure is commonly performed to treat certain types of glaucoma and prevent angle-closure glaucoma.
Iris: The iris is the colored, circular structure surrounding the pupil of the eye. It is responsible for controlling the amount of light that enters the eye by adjusting the size of the pupil, which is the opening at the center of the iris.
Keratitis: Keratitis is the inflammation of the cornea, often caused by infections, injury, or underlying diseases. It can lead to pain, vision problems, and even blindness if not treated promptly.
Keratoconjunctivitis sicca: Keratoconjunctivitis sicca, also known as dry eye syndrome, is a condition where the eyes do not produce enough tears or the tears evaporate too quickly. This results in dryness, irritation, and inflammation of the cornea and conjunctiva.
Lacrimal Glands: Lacrimal glands are exocrine glands located in the upper, outer part of each eye that produce tears. They are responsible for the continuous secretion of tears that help maintain the health and lubrication of the eye's surface.
Lens: The lens is a transparent, flexible structure located behind the iris of the eye. It is responsible for refracting and focusing light onto the retina, allowing for clear vision at various distances.
Lifitegrast: Lifitegrast is a prescription eye drop medication used to treat the signs and symptoms of dry eye disease. It works by reducing inflammation in the eyes and improving the quality of tear film, which is essential for maintaining healthy eyes.
Macula: The macula is a small, highly sensitive area of the retina responsible for central, detailed vision. It is the area of the eye that provides the sharpest and most precise visual acuity, allowing us to see fine details and colors with clarity.
Macular degeneration: Macular degeneration is a medical condition that results in the deterioration of the central portion of the retina, known as the macula. This leads to progressive vision loss, particularly affecting central vision.
Macular Degeneration: Macular degeneration is a leading cause of vision loss in older adults, characterized by the deterioration of the macula, the central part of the retina responsible for sharp, central vision. It is a progressive condition that can significantly impact a person's ability to read, drive, and perform other daily tasks requiring clear central vision.
Myopia: Myopia, also known as nearsightedness, is a common refractive error where distant objects appear blurry while close objects are seen clearly. It occurs when the eye shape causes light rays to focus in front of the retina instead of on it.
Open-angle glaucoma: Open-angle glaucoma is a chronic eye condition characterized by progressive damage to the optic nerve due to increased intraocular pressure. It is the most common form of glaucoma and can lead to vision loss if untreated.
Open-angle Glaucoma: Open-angle glaucoma is a chronic, progressive eye condition characterized by increased intraocular pressure, which can damage the optic nerve and lead to vision loss if left untreated. It is the most common type of glaucoma and is typically associated with the topics of Introduction to the Eyes and Antiglaucoma Drugs.
Optic Nerve: The optic nerve is a bundle of nerve fibers that transmits visual information from the retina to the brain, allowing us to see. It is a crucial component of the visual system, connecting the eyes to the visual processing centers in the brain.
Orbital cellulitis: Orbital cellulitis is a serious infection involving the tissues surrounding the eye, including the eyelids, eyebrow, and cheek. It can lead to vision loss and other complications if not treated promptly.
Pediatric clients: Pediatric clients are children and adolescents who require medical care, including pharmacological treatments. Special considerations must be made for their unique physiological and developmental needs.
Photophobia: Photophobia is a condition characterized by an increased sensitivity to light, causing discomfort or pain in the eyes. It is often associated with various ocular and systemic conditions.
Presbyopia: Presbyopia is an age-related condition in which the eye's lens loses its ability to focus on close objects. It commonly begins to affect individuals over the age of 40.
Prostaglandin Analogs: Prostaglandin analogs are synthetic compounds that mimic the structure and function of naturally occurring prostaglandins, a group of lipid-derived signaling molecules that play a crucial role in various physiological processes, including the regulation of intraocular pressure. These analogs are primarily used in the treatment of glaucoma, a leading cause of blindness worldwide.
Pupil: The pupil is the opening in the center of the iris of the eye that allows light to enter the eye. It is responsible for controlling the amount of light that reaches the retina, which is essential for proper vision.
Refractive errors: Refractive errors are vision problems that occur when the shape of the eye prevents light from focusing directly on the retina. Common types include myopia, hyperopia, astigmatism, and presbyopia.
Retina: The retina is the light-sensitive layer of tissue at the back of the eye that converts light into electrical signals, which are then transmitted to the brain for visual processing. It is a crucial component of the visual system and plays a vital role in enabling sight.
Rods: Rods are photoreceptor cells in the retina of the eye responsible for vision at low light levels. They do not mediate color vision and have a low spatial acuity.
Sclera: The sclera is the white, protective outer layer of the eye that covers the entire eyeball, except for the cornea. It is a tough, fibrous membrane that helps maintain the shape and structure of the eye.
Stye: A stye is a red, painful lump near the edge of the eyelid, caused by an acute infection of the oil glands. It can be treated with warm compresses and, in some cases, antibiotic ointments or drops.
Trabecular Meshwork: The trabecular meshwork is a specialized tissue located at the angle of the anterior chamber of the eye. It plays a crucial role in the regulation of intraocular pressure (IOP) and is a key component in the pathogenesis and treatment of glaucoma.
Trabeculectomy: Trabeculectomy is a surgical procedure used to treat glaucoma by creating an opening in the eye's trabecular meshwork to allow fluid to drain, reducing intraocular pressure. This helps prevent damage to the optic nerve and vision loss.
Trabeculectomy: Trabeculectomy is a surgical procedure performed to create an opening in the sclera (the white of the eye) to allow excess fluid to drain from the eye, thereby reducing intraocular pressure (IOP) in individuals with glaucoma. This procedure is a common treatment option for managing open-angle glaucoma, a condition characterized by increased eye pressure that can lead to optic nerve damage and vision loss if left untreated.
Trabeculoplasty: Trabeculoplasty is a surgical procedure used to treat open-angle glaucoma by improving the drainage of aqueous humor from the eye. It involves using laser energy to modify the trabecular meshwork, the primary site of outflow resistance in the eye, to enhance fluid drainage and lower intraocular pressure.
Uveitis: Uveitis is an inflammation of the uvea, the middle layer of the eye which includes the iris, ciliary body, and choroid. It can cause redness, pain, light sensitivity, and vision changes.
Vitreous Humor: The vitreous humor is a clear, jelly-like substance that fills the space between the lens and the retina at the back of the eye. It helps maintain the shape of the eye and plays a crucial role in the structure and function of the visual system.
Wet macular degeneration (WMD): Wet macular degeneration (WMD) is an eye condition that leads to the deterioration of the central portion of the retina, known as the macula. It is characterized by abnormal blood vessel growth under the retina which can leak fluid or blood.