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Eye Lecture

QuestionAnswer
Extra-ocular eye structures Eyebrows, Eyelids Eyelashes, Conjunctiva
Intra-ocular eye structures Cornea, Iris, Pupil, Anterior chamber, Lens, Retina, Optic nerve. Responsible 4:Transmitting visual images to the brain.Maintaining homeostasis of the inner eye
Cataract definition Waterfall. Cloudiness of the eye's lens that causes vision loss.
Eye physiology Normal Lens: Clear transparent button-like structure that lies behind the Iris and Pupil. Works much like a camera lens: focuses light onto the film where an image is recorded.Focuses light onto the retina at the back of the eye where an image is recorded
Eye physiology Lens also adjusts the eye's focus: can see objects clearly both up close and far away; made of mostly water and protein. Protein is arranged in a precise way that keeps the lens clear for the light to pass through it.
Cataract pathophys some of the protein may clump together and begin to cloud a small area of the lens. Eye lens becomes cloudy = blurred & unclear view. Normal part of aging process. 1 may be worse than the other b/c ea cataract develops & progresses at diff rate
Cataract progression Some ppl won't notice b/c it's not bad; others will lose all vision. Starts at periphery and moves into the center.
Cataract risk factors: Aging Aging: senile cataracts: Changed proteins and fibers in the lens. Degenerated lens from the wear and tear. Eventually lens will loose its clarity. Most start after 65, but some in 40s & 50s.
Cataract risk factors Congential: If woman contracts the German measles early in pregnancy: unborn child may have congenital cataracts. Smoking: potentially damaging lens proteins & fiber cell membrane in the lens. Long-term use of corticosteroids: alter protein metabolism
Cataract risk factors Systemic disease: DM or Hypothyroidism Exposure to radiation or long hours of bright sunlight Other eye disorders: inflammation of iris or ciliary body
Types of cataracts Immature:affected only a portion of the lens Mature: opacity of the entire lens. Most significant form of cataract Has the appearance of “frost on a window” Ripen cataract
Clinical Manifestations of cataracts Starts out small: has little effect. May noticed slight blurred vision: looking through a cloudy piece of glass. Color diminished. Glare from headlights or sun too bright due to light bouncing off opacity. Never happy with new glasses. Double vision.
Diagnostic tests for cataracts Standard eye: acuity & field (card pts) Ophthalmoscopic examination: aka fundoscopy Examining eye Fundus: Retina, Optic disc, Macula, & Retina vessels
Diagnostic tests for cataracts Slit-lamp: various shapes & colors of light: Admin eye drops to dilate pupils. Exam the front surface of the eye: cornea sclera ant. chamber trabecular meshwork Glare test: Vision drops considerably in sunlight or when looking at lights
Diagnostic tests for cataracts Contrast Sens.: Crispness of vision: enable to see objects that don't stand out from background. Good contrast sensitivity is when they see objects even when they are displayed against increasingly low-contrast backgrounds
Cataract surgery Only effective tx: remove lens & replace with plastic. v. effective: 1.5 mil/year, non-emergent, usually done when vision changes are bad
Phacoemulsification surgery Outpt, v. sm incision =a 3 mm or 1/8th ". breaks up the cloudy with sound waves & removes thru vacuum back 1/2 of the lens is left. plastic disc, aka intraocular lens is folded and inserted to provide light refraction and restore visual acuity
Extracapsular surgery Advanced cataract: can't break up the clouded lens Requires larger incision, about 2/10 inch (10 mm) Remove lens as one piece
Complications from surgery 2-5% of sx, Loss of vitreous humor (gel-like substance in the back of the eye allowing light to the retina), Cornea edema, Increased intra-ocular pressure, Hemorrhage, Inflammation, Retinal detachment, Displacement of implanted lens.
Scar tissue in cataracts 20-35% of pts may have a thin film scar tissue formed behind the newly implanted Lens causing blurred vision. Feels as cataract has "grown back." Cloudiness usually develops a year or more after surgery causing same vision problems as a cataract does.
YAG Capsulotomy Uses a laser beam to make a tiny hole in the post capsule to allow the light to pass through to reach the retina. Painless out-patient surgery takes 5 minutes. Not require repeated cataract surgery. Approximately 98% of pts experience vision improveme
Glaucoma Characterized by increased intra-ocular pressure & vision loss. Increased ocular pressure = Fluid within the eye (aqueous humor) does not drain properly
Aqueous humor: structure and function Thick fluid in the eye. Occupies both anterior & posterior chambers Delivers essential nut. to the non-vasc tissues of the ant chamber (cornea, lens, & trabecular meshwork) Removes metabolites from the eyes to provide the proper environment for the ey
Aqueous humor: structure and function Produced by Ciliary body, flows from the Posterior chamber to the Anterior chamber, and outflow through Trabecular meshwork to Canal of Schlemm
Intra-ocular pressure Normal IOP: 12-20 mm/Hg. Maint pressure by a balance between the production of aqueous humor in the Ciliary body and its outflow through Canal of Schlemm. Disrupted balance = Increased IOP Increased intra-ocular pressure = Damage optic nerve
Glaucoma pathophys Deteriorated optic nerve = Develop blind spots & vision change Affected peripheral vision 1st then front or central vision. Eventually = blindness without tx 2% of pop 40+ in U.S. Leading cause of blindness in the U.S. 13% of all blindness worldwid
Closed Angle: Acute Glaucoma less common: med emerg. Anatomical changes of angle between the Pupil & lateral Cornea associated with pupillary dilation. When pupils are dilated, the iris is displaced toward the cornea which narrows/closes the anterior chamber angle.
Closed Angle: Acute Glaucoma Closed off aqueous humor exit so it accum = incr IOP. May occur when a person is sitting in a darkened room or during the time of stress: dilated pupil.
Risk factors for acute angle Glaucoma Elderly, Farsightedness (have small eyes), Stress Anything that causes the pupil to dilate (i.e. dim lighting) Certain medications like anti-histamines (anti-cholinergic effect with pupillary dilation)
Clinical manifestations for acute angle glaucoma May be rapid, no warning, in dim room, pup dilated. It affects one eye: other eye is at risk in the future. Severe throbbing eye pain and headache Redness in eye, Blurred vision, Halos around light Tender and firm eyeball, Fixed and dilated pupil N-V
Open Angle Glaucoma aka Chronic simple glaucoma most common. Normal anterior chamber angle between the iris and cornea. Relatively obstructed AH flow thru Trabecular meshwork and into the Canal of Schlemm (but idiopathic closure)= slow incr of IOP. both eyes, but not symmetrical. silent thief of night
Risk factors for open angle glaucoma Age over 40 years old, Family history of Glaucoma Diabetes, Nearsightedness (expanded eye thinning the support structures for the optic nerve?)
Clinical manifestations of open angle glaucoma vague: unhappy with new glasses, blurred vision, Halos around light. Difficulty with color presentation Hard time to find the way into the seat at theater. Eyes may feel hard to the touch Mild, chronic headache Peripheral vision loss
Diagnostic tests for open angle glaucoma: Non-Contact Tenometry Non-Contact Tenometry: puff of air measures the air force that flattened the cornea. Thick cornea: higher IOP requires greater air pressure to flattened the cornea. 40+ y/o done annually. IOP > 26 consist: incr chance by 50% IOP >30 consist: 100%
Diagnostic tests for open angle glaucoma: pupillary reflex and refraction Pupillary Reflex: Non-reactive pupil in affected eye Refraction: Myopia: nearsightedness: Distant objects appear blurry Eye is longer than usual Image falls short of the retina. Most common vision problem Hyperopia: farsightedness Abnormal small eye
Refraction test: astigmatism Cornea curves more severely like a football. All objects both near and far are distorted. Images are blurred due to some of the light rays are focused and others are not
Refraction test: Presbyopia: “old eye” Inability to focus on objects thatare close to self. Need reading glasses Lens starts to lose its flexibility.
Medical management of open angle glaucoma Treatment goal: To reduce the intra-ocular pressure. Depending on the type of glaucoma: achieved by medications or surgery
Medications for open angle glaucoma general Oral, IV, Topical eye drops Can’t cure glaucoma: Control IOP to preserve vision indefinitely with drug therapy Can be used alone or in combination Four major types of drugs Decrease production of aqueous humor Increase drainage of aqueous humor.
Beta blocker for open angle glaucoma Affects Ciliary body where the Aquous humor is being produced. Decrease production of AH by the Ciliary body. Effective and have low side effects Usually applied BID Timoptic: most common drug
Adrenergic Agonist for open angle glaucoma Increases drainage of aqueous humor. May cause ocular redness Glaucon (Epinephrine): common drug
Cholinergic Agonists for open angle glaucoma Increase drainage of aqueous humor Mild miotic effect that constrict pupil Have a short duration of action Cause blurred vision. Pilocarpine: common drug
Pilocarpine insert Ocusert ocular therapeutic system for Pilocarpine Effect of Pilocarpine lasts for 2-4 hours: conventional method. Placed in the upper or lower sac of the eye to allow Pilocarpine to slowly diffuse out over 7 days.
Carbonic Anhydrase Inhibitors for open angle glaucoma Decrease the production of aqueous humor. Systematic drugs that can be given by orally or intravenously. Usually used as adjunctive therapy. Given in combination of any of the above topical eye drops. Diamox: common drug
Osmotic Agents for open angle glaucoma Mannitol: common drug Hypertonic solution to draw fluid from the eye = Decrease IOP Used in emergency treatment for acute angle-closed glaucoma
Prostaglandins for open angle glaucoma Hormone-like substances that help open blood vessels Increase outflow of aqueous humor Drugs: xalatan, rescula, travatan, lumigan
Trabeculoplasty LOOK UP
Iridotomy It is frequently used to treat angle-closure glaucoma. Make small drainage hole in the iris to allow the aqueous humor to drain more freely So the iris does not plug up the trabecular meshwork.
Cyclophotocoagulation Freezing selected areas of the ciliary body to reduce the aqueous humor production. Used for more advanced or aggressive cases.
Macular Degeneration: definition and general Referred to age-related macular degeneration (ARMD) or senile macular degeneration (SMD) Leading cause of blindness 60+y/o in U.S. Considered as aging process. men & women equally 2 mil new cases are diagnosed annually < 1% is successfully treated.
Macular Degeneration: definition and general Exact cause is unknown Suggested that it results from the changes to the macular as the macula deteriorates or becomes scarred
Macular degeneration pathophys M in center of Retina. light enters the eyes & is focused by Cornea & Lens ->Retina. Retina has photo-sensitive cells that line the back of the eye respons 4 color and fine vision. concentration of photo-sensitive cells are found in Bull-Eye: Macula
Closed Angle: Acute Glaucoma less common: med emerg. Anatomical changes of angle between the Pupil & lateral Cornea associated with pupillary dilation. When pupils are dilated, the iris is displaced toward the cornea which narrows/closes the anterior chamber angle.
Closed Angle: Acute Glaucoma Closed off aqueous humor exit so it accum = incr IOP. May occur when a person is sitting in a darkened room or during the time of stress: dilated pupil.
Risk factors for acute angle Glaucoma Elderly, Farsightedness (have small eyes), Stress Anything that causes the pupil to dilate (i.e. dim lighting) Certain medications like anti-histamines (anti-cholinergic effect with pupillary dilation)
Clinical manifestations for acute angle glaucoma May be rapid, no warning, in dim room, pup dilated. It affects one eye: other eye is at risk in the future. Severe throbbing eye pain and headache Redness in eye, Blurred vision, Halos around light Tender and firm eyeball, Fixed and dilated pupil N-V
Open Angle Glaucoma aka Chronic simple glaucoma most common. Normal anterior chamber angle between the iris and cornea. Relatively obstructed AH flow thru Trabecular meshwork and into the Canal of Schlemm (but idiopathic closure)= slow incr of IOP. both eyes, but not symmetrical. silent thief of night
Risk factors for open angle glaucoma Age over 40 years old, Family history of Glaucoma Diabetes, Nearsightedness (expanded eye thinning the support structures for the optic nerve?)
Clinical manifestations of open angle glaucoma vague: unhappy with new glasses, blurred vision, Halos around light. Difficulty with color presentation Hard time to find the way into the seat at theater. Eyes may feel hard to the touch Mild, chronic headache Peripheral vision loss
Diagnostic tests for open angle glaucoma: Non-Contact Tenometry Non-Contact Tenometry: puff of air measures the air force that flattened the cornea. Thick cornea: higher IOP requires greater air pressure to flattened the cornea. 40+ y/o done annually. IOP > 26 consist: incr chance by 50% IOP >30 consist: 100%
Diagnostic tests for open angle glaucoma: pupillary reflex and refraction Pupillary Reflex: Non-reactive pupil in affected eye Refraction: Myopia: nearsightedness: Distant objects appear blurry Eye is longer than usual Image falls short of the retina. Most common vision problem Hyperopia: farsightedness Abnormal small eye
Refraction test: astigmatism Cornea curves more severely like a football. All objects both near and far are distorted. Images are blurred due to some of the light rays are focused and others are not
Refraction test: Presbyopia: “old eye” Inability to focus on objects thatare close to self. Need reading glasses Lens starts to lose its flexibility.
Medical management of open angle glaucoma Treatment goal: To reduce the intra-ocular pressure. Depending on the type of glaucoma: achieved by medications or surgery
Medications for open angle glaucoma general Oral, IV, Topical eye drops Can’t cure glaucoma: Control IOP to preserve vision indefinitely with drug therapy Can be used alone or in combination Four major types of drugs Decrease production of aqueous humor Increase drainage of aqueous humor.
Beta blocker for open angle glaucoma Affects Ciliary body where the Aquous humor is being produced. Decrease production of AH by the Ciliary body. Effective and have low side effects Usually applied BID Timoptic: most common drug
Adrenergic Agonist for open angle glaucoma Increases drainage of aqueous humor. May cause ocular redness Glaucon (Epinephrine): common drug
Cholinergic Agonists for open angle glaucoma Increase drainage of aqueous humor Mild miotic effect that constrict pupil Have a short duration of action Cause blurred vision. Pilocarpine: common drug
Pilocarpine insert Ocusert ocular therapeutic system for Pilocarpine Effect of Pilocarpine lasts for 2-4 hours: conventional method. Placed in the upper or lower sac of the eye to allow Pilocarpine to slowly diffuse out over 7 days.
Carbonic Anhydrase Inhibitors for open angle glaucoma Decrease the production of aqueous humor. Systematic drugs that can be given by orally or intravenously. Usually used as adjunctive therapy. Given in combination of any of the above topical eye drops. Diamox: common drug
Osmotic Agents for open angle glaucoma Mannitol: common drug Hypertonic solution to draw fluid from the eye = Decrease IOP Used in emergency treatment for acute angle-closed glaucoma
Prostaglandins for open angle glaucoma Hormone-like substances that help open blood vessels Increase outflow of aqueous humor Drugs: xalatan, rescula, travatan, lumigan
Trabeculoplasty LOOK UP
Iridotomy It is frequently used to treat angle-closure glaucoma. Make small drainage hole in the iris to allow the aqueous humor to drain more freely So the iris does not plug up the trabecular meshwork.
Cyclophotocoagulation Freezing selected areas of the ciliary body to reduce the aqueous humor production. Used for more advanced or aggressive cases.
Macular Degeneration: definition and general Referred to age-related macular degeneration (ARMD) or senile macular degeneration (SMD) Leading cause of blindness 60+y/o in U.S. Considered as aging process. men & women equally 2 mil new cases are diagnosed annually < 1% is successfully treated.
Macular Degeneration: definition and general Exact cause is unknown Suggested that it results from the changes to the macular as the macula deteriorates or becomes scarred
Macular degeneration pathophys M in center of Retina. light enters the eyes & is focused by Cornea & Lens ->Retina. Retina has photo-sensitive cells that line the back of the eye respons 4 color and fine vision. concentration of photo-sensitive cells are found in Bull-Eye: Macula
Macular degeneration physiology macula provides sight in the center of our visual field; is responsible for clear, sharp, straight-ahead vision needed for reading, writing, driving, doing close work.
Macular degeneration pathophys In aging, the cells in the macular zone break down and thin: causes a malfcn or lost fcn. Brain may compensate & fill in the missing part of the picture in early cases with spotty macular cell damage or dysfcn. disease is fairly advanced when symp occur
Risk factors for Macular degeneration No known cause for AMD Family history Smoker Elderly Caucasians, especially northern European descent: more ultraviolet rays reach the retina in blue-eye individuals because of the lower pigment density in the eye.
Types of Macular degeneration Dry/atrophic and wet/exudate
Dry Macular degeneration AKA Atrophic Approximately 90% of cases Caused by aging and thinning of the tissue of the macula. Generally experience a gradual loss of central vision. No treatment or cure.
Wet Macular degeneration 10% of ARMD cases Macula is forming the scar tissue as blood vessels around the macula are leaking Has more sudden, rapid vision loss Has permanent vision loss = accounts for 90% of all cases of legal blindness.
Clinical manifestations of macular degeneration Rapid & severe or gradual vision loss. Only 1 eye loses vision Dim or Distorted esp when reading. Gradual loss of color May still have good side vision, but dark or blank spots appear in the center of vision. Straight lines look wavy
Amsler Grid test for macular degeneration detect blind spots or distortion of central vision. Wear reading glasses chart at arms distance & cover one eye. stare at the white dot in the center of grid. Holes, blurry spots, wavy, fuzzy, crooked, distorted, or broken line: ARMD
Medical Management for macular degeneration No specific, definitive treatment or cure for MD. Treatment goal: assist pt see better & stabilize the condition
Angiogenesis Inhibitor for macular degeneration Pegaptanib (Macugen): first drug to directly slow down the disease process Impeding vascular endothelial growth factor (VEGF): inhibit new blood vessel formation and its subsequent leakage. Needs 9 separate injections given 4-6 weeks apart
General info about macular degeneration Lost vision can't be restored. Only lose central. Low vision aids can help pts fcn (telescopic and microscopic lenses, mag glasses, needle threader, large print books, etc).
Photocoagulation treatment for macular degeneratio Laser surgery of the eye to coagulate leaky blood vessels and to destroy the abnormal vessels may be useful in the early stage of the disease. Effectiveness of this laser photocoagulation treatment is limited to small numbers of patients with wet form.
Prognosis and prevention for macular degeneration Prog: will affect for rest of life Prev: no known, reg eye exams, avoid anything that blocks blood flow: fat, cholesterol. Sunglasses for UV light. Eat green leafy veggies. No smoking.
Diet for macular degeneration Low fat, cholesterol. Lots green leafy veggies. Anti-oxidant supplements: vit c, e, beta caratene, zinc, decrease fatty deposits on vessels. Can slow, but not reverse process. Good for people over 50 who have not eaten these during life.
Created by: Marissagostanian