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Ocular Disease as a Result of
Diabetes and Aging
By: Sandra
Overview of the Eye
•Provides sight
•Eye is a ball a little over one inch in diameter
•Located in the inner orbit of a cone-shaped socket in
skull
•Has interior and exterior
•Outer parts of the eye include eyelids,
conjunctiva, lacrimal glands
•Primary function of exterior is to keep eye clean
•Interior of eye controls sight
Exterior Structures of the Eye
•Eyelids – Keep dust and foreign particles out of eye
•Conjunctiva – Keeps the eye clean and lubricated
•Lacrimal Gland – Produce tears to moisten eye
•Lacrimal Sac – Location that leads
to the nose into where
tears drain
Interior Structures of the Eye
•Sclera – Tough tissue that composes outer layer of eyeball (white
portion)
•Cornea – Clear portion of the eye
•Uveal tract – Middle layer of the eyeball, consisting of iris,
ciliary body, and choroid
•Iris – Colored portion of the eye
•Ciliary Body – Portion of eye that surrounds iris
•Choroid – Thin membrane in eye, giving nutrients to eye
•Vitreous Humor – jelly-like substance that keeps the eye’s shape
•Retina – Innermost layer of eyeball wall
•Pupil – Dark dot in middle of the eye that allows for vision
Functions of those Structures
•Eye’s power of sight comes primarily from interior
structures
•Iris houses the pupil
•Muscles in iris cause pupil to contract or expand to adjust
amount of light that enters eye
•Behind the pupil is a lens that is adjusted for clearer vision
•Vision comes from absorption of light
•Rods and cones in retina absorb light that are converted
to colors, then converted into electrical signals
•Electric signals are converted into images by way of the
optic nerve
Effect of Diabetes on the Eyes
•Diabetes causes diseases of the body’s blood vessels
•Blood is supplied to retina through central retinal artery
•When blood vessels do not function correctly, nutrients
cannot reach retina
•That leads to risk of developing diseases like diabetic
retinopathy and glaucoma
•May sometimes even lead to blindness
•“Diabetes is leading cause of new cases of legal blindness in
US”
Diabetic Retinopathy
•
There are three stages:
1. Background Diabetic Retinopathy
2. Diabetic Macular Edema
3. Proliferative Diabetic Retinopathy
•
Affects the retina, primarily the macula
•
Blood vessels blocked and small hemorrhages in retina
•
New blood vessels – microaneurysms – form and leak
•
Can cause retina to swell and damage vision
•
Vessels may block blood to central vision, leading to
permanent vision loss
Symptoms & Diagnosis of DR
•No symptoms, so early detection is key
•Diagnosis:
•flourescein angiogram performed to determine source of
leakage
•Pigmented dye injected into arm vein
•Dye is photographed 30 times within ten minute span
•Dilated Retinal Eye Exam
•Dilation – best way to see clearly into eye
•Every two years is best for this exam
Treatment of DR
•Laser Surgery
•Light aimed into retina to seal leaking blood vessels
•Also prevents further formation of abnormal blood
vessels
•25 minute procedure
•Only eye drop anesthesia necessary
•For Proliferative Diabetic Retinopathy
•Laser process called “focal” or “gridphotocoagulation”
•Seals leaking blood vessels
•Prevent further abnormal growth
Glaucoma
•Causes gradual degeneration of optic nerve cells due to pressure
•Several types:
•Chronic open-angle, acute closed-angle, low-tension,
congenital
•Acute glaucoma – vision loss comes rapidly, can be 24 hours
•Chronic open-angle – most common
•Caused by open angle in front chamber of eye
•Vision loss is not as rapid
•Low-tension – only the optic nerve is damage, pressure is
normal
•Congenital – inherited and affects infants
Symptoms & Diagnosis of Glaucoma
•Symptoms in the eye include:
•Increased intraocular pressure due to poor drainage of aqueous humor
•Trabecular meshwork (drainage system) functions incorrectly
•Optic nerve suffers increased pressure and nerve fibers die
•Visible symptoms:
•Short-term dimmed or fogged vision, colored ring around artificial
lights, pain in forehead, ears, teeth, eye looks inflamed
•Diagnosis:
•Examination with tonometer from ophthalmologist
•Check pressure in eye
•Slit lamp – examines optic nerve after pupil dilation
•Optic disk appears indented and looks pale yellow – lack of blood
Treatments of Glaucoma
•Traditional medicines:
•Reduce intraocular pressure
•Prostaglandins, beta blockers, miotics, adrenergics
•Decrease pressure in eye by reducing aqueous humor
production
•Miotics enhance capacity of drainage system
•Laser surgery:
•Laser trabeculoplasty, necessary if too much pressure is there
•Sparks fluid drainage by expanding existing holes in
drainage
•Laser Iriditomy – Small opening made outside iris for drainage
•Conventional Incisional Surgery:
•New drainage system created in eye to replace old one
Effects of Aging on the Eyes
•Aging makes eye more vulnerable to developing diseases
•Minor conditions include:
•Presbyopia – ability to see close objects starts to deteriorate
•Lens gets hard and less flexible
•Floaters – pieces of vitreous humor break away and float in
eye
•Usually pretty common in those over age of 50 years of age
•More serious diseases include:
•Cataracts, Age-Related Macular Degeneration, Corneal
Disease
Age-Related Macular Degenration
•Damages central vision at macula
•Most common cause of blindness in United States
•Affects Retina
•Two forms: Wet AMD and Dry AMD
•Dry AMD – less serious and more common – 90% of all cases
•Fatty deposits seen under retina’s light-sensing cells
•Supportive layer becomes smaller
•Wet AMD – more serious and also more rare case
•Neovascularization occurs – new blood vessel growth
•They can break or leak to cause damage to eye
Symptoms & Diagnosis of AMD
•Generally affect Caucasian males over age of 50 and
smokers
•Dry AMD:
•Cause is unknown
•Symptoms include: Distorted reading vision, blurred
vision, distorted vision
•Wet AMD:
•Symptoms include: Distorted vision, quick vision loss,
seeing colors that appear faded
•Blind spot at center of field of vision
•Symptoms of dry AMD evident, at greater extent
•Diagnosis: Pupil dilation and Amsler Grid Test
Treatments of AMD
•No treatment for dry AMD
•Treatment for wet AMD includes:
•Laser photocoagulation – laser heat beam seals broken
vessels
•May lead to vision loss from blind spots
•Visudyne Therapy – Two-part process
•Visudyne injected into arm and goes to spot of eye
where blood vessels do not belong
•Laser then activates visudyne to kill abnormal cells
•Slows damage to retina
Cataracts
•Characterized by clouding of eye’s lens
•Almost like looking through frosted / yellow-tinted window
•Not a film, not caused by overuse of eye, does not cause
irreversible blindness
•Caused by sclerosis in lens
•Lens is less transparent and thickened
•Could be caused by lifetime of exposure to ultra-violet
radiation
•Smoking and alcohol also increase risk
•Medical problems, diabetes, and family history also
increases risk
Symptoms & Diagnosis of Cataracts
•Symptoms:
•Blurred vision, bad night vision, double vision in one eye
•Increased sensitivity to light
•Need brighter light for reading
•Seeing faded colors
•Diagnosis:
•Check sharpness of vision with Snellen Chart
•Pupil dilation test – examine lens and optic fibers
•Slip lamp – look inside eye to see cataract up close
Treatment of Cataracts
•Less severe cases:
•Increased eyeglass prescription
•Eye drops can allow more light to enter eye
•More serious cases:
•Three types of cataract removal surgery
•Extracapsular surgery & intracapsular surgery
•Incision is made in eye, cataract is then removed
and plastic lens, called intraocular lens, inserted
•Phacoemulsification
•Uses high-frequency ultrasound
•Breaks cataract apart for easy removal
Fuch’s Corneal Dystrophy
•More prevalent in women than men
•Progresses slowly and affects both eyes
•Inherited
•Affects 50 – 60 year-olds, but can be detected in 30 – 40
year-olds
•Caused by deterioration of endothelial cells
•Lack of endothelial cells leads to bad water drainage
•Leads to swelling and shape-change of cornea
•Exact cause of endothelial cell loss is unknown
•Could be caused by inflammation in eye
Symptoms & Diagnosis of FCD
•No visible symptoms until later in stage of disease
•Vision becomes blurred and distorted
•Typically wake up with distorted and blurred vision
•When eyes are closed, liquid cannot be evaporated
•As day progresses, vision clears up
•Diagnosis:
•Slit lamp used to magnify cornea
•Like an “optical microscope”
•Small bumps seen on cornea
Treatment of Fuch’s Corneal Dystrophy
•Treatments vary depending on severity of disease
•Early stages:
•Salt-water eye drops to soak up excess water before
entering cornea
•Blow hot air into eye to dehydrate it
•Soft-bandage contacts lens – relieve corneal blisters
•More serious cases:
•Corneal surgery may be necessary
•Cornea transplant to restore vision
Prevention
•Eyes are important and provide precious sense of sight
•Though eye disease cannot fully be prevented, you can
lower the risk
•Keep good health and good nutrition
•Get lots of vitamins, beta-carotene, anti-oxidants
•Protect eyes from sunlight and ultra-violet radiation
•Get eye checks frequently
•Every two years in young age
•Every year at age 30 or older
•Every six months if family history of certain diseases
Works Cited
“Aging and Your Eyes.” Sep. 2002. AgePage. National Institute on Aging. 19 Oct.
2004. <http://www.niapublications.org/engagepages/eyes.asp>.
“Cataract.” Medical Library. Jan 2003. 9 Nov 2004.
<http://www.medem.com/medlb/article_detaillb.cfm?article_ID=ZZZS
XEVUF4C&sub_cat=119>.
Chang, Maragret, M.B. Personal Interview. 28 Oct. 2004.
“Ocular Symptoms and Diagnosis.” Diabetic Eye Disease. Richmond Eye
Associates. 19 Oct. 2004 <http://www.richmondeye.com/diab1.htm>.
Forrest, James, M.B. The Recognition of Ocular Disease. 7th ed. London: The
Hatton Press Ltd, 1952.
“Fuch's Corneal Endothelial Dystrophy.” 23 Nov. 2004. <http://www.waeyemd.org/W_Fuch's_corneal_dystrophy.htm>.
“Fuch's Dystrophy.” 2001. VisionWorks, Inc. 19 Nov. 2004.
<http://www.visionworksusa.com/disease.asp?d_num=31>.
Harvard Medical School. The Aging Eye. New York: Simon & Schuster, 2000.
“If You Thought Eyeglasses Could Solve All Eye Problems, Read On.” Eye Disease.
The WhyFiles. 25 Oct. 2004. <http://whyfiles.org/003eye/statistics.htm>.
Vision Problems in the United States. Bethesda: National Eye Institute, 2002.