Diseases of the Eye 101

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Diseases of the Eye 101

• Ravi Berger, M.D.
• KU Department of Ophthalmology

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Overview

• Age Related Macular Degeneration
• Congenital Dystrophies
• Drug-Induced Miosis
• Marfans Syndrome
• Retinopathy of Prematurity

• Aniridia
• Achromatopsia
• Amblyopia
• Pathologies Affecting Visual Fields
• Visual Field Testing

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Dystrophies

• Epithelial Basement Membrane Dystrophy
• Most common of all corneal dystrophies
• Map-Dot-Fingerprint changes and intraepithelial
  microcysts
• Symptoms associated with recurrent corneal
  erosions
• Pain, foreign body sensation, photophobia, and
  tearing, especially with the opening of the lids
  during skeep or awakening in the morning

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Dystrophies
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Dystrophies

• Fuchs Dystrophy
• The most common reason for corneal transplants
• 5th to 6th decade of life
• Inability to maintain proper hydration of cornea
  due to decompensating endothelium
• Guttatae, stromal thickening, epithelial edema,
  and subepithelial fibrosis

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Dystrophies

• Stargardts Macular Dystrophy
• Discrete yellowish round flecks at the level of
  the RPE
• Progress to geographic atrophy in the macula?
  beaten bronze appearance
• Mutation in ABCR gene leading to abnormality in
  rod outer segment membrane
• Fluorescein Angiography? Dark Choroid
• No treatment available

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Dystrophies

• Best Vitelliform Dystrophy
• Yellow yolk-like macular lesion in childhood
• Breaks down with scarring and geographic atrophy
  later in life
• /- choroidal neovascular-ization
• Potentially visually devestating
• Lipofuscin accumulations within RPE cells and in
  sub-RPE space throughout fundus

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Marfans Syndrome

• Disorder of connective tissue (mutation in
  Fibrillin gene on chromosome 15)
• Autosomal dominant
• Associated findings
• Arachnodactyly, aortic aneurysms, long extremities

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Marfans Syndrome

• Lens dislocation (Ectopia lentis)
• Bilateral
• Symmetric
• Usually superior and temporal
• Zonular attacments remain intact, but become
  stretched and elongated
• Associated ocular findings
• Axial myopia
• Retinal detachment
• Secondary glaucoma due to pupillary block
• High rate of complications with lens extraction
• Reading Add required

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Aniridia

• Absence of iris
• Rudimentary iris stubs with PAS
• Anterior chamber incompletely developed
• Dominant or Recessive (PAX 6 gene, on chromosome
  11)
• A panophthalmic disorder with associated
  findings
• Subnormal visual acuity
• Congenital nystagmus
• Strabismus
• Corneal pannus
• Cataracts
• Ectopia lentis
• Glaucoma (very high incidence)
• Optic nerve hypoplasia
• Foveal or macular hypoplasia

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Aniridia

• Nonfamilial aniridia assosciated with WAGR
• Wilms tumor, Aniridia, Genitourinary anomalies,
  and mental Retardation
• A contiguous gene deletion syndrome (involving
  nearby genes in the region at 11p13)

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Achromatopsia

• Absence of color discrimination
• Classified in two forms
• blue cone monochromatism
• Rod monochromatism
• ERG shows absence of conventional cone response,
  while rod response is relatively normal

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Achromatopsia

• Rod monochromatism is true color blindness
• No cone function at all
• World seen in shades of gray
• Assocaiated opthalmic problems
• Congenital nystagmus
• Poor visual acuity
• Photoaversion

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Age Related Macular Degeneration

• Leading cause of severe central visual acuity
  loss in one or both eyes for people over age 50
  in USA

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Age Related Macular Degeneration

• Visual blurring
• Central scotoma
• Metamorphopsia
• Micropsia/Macropsia

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Age Related Macular Degeneration

• Who gets macular degeneration?
• Greatest statistical association is with
  increasing age

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Age Related Macular Degeneration

• Risk Factors
• Age gt 55
• Female Gender (exudative type)
• Caucasian
• Smoking
• Poor Nutrition
• Photic exposure (UV)
• Hypertension

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Age Related Macular Degeneration

• The normal clinical macula
• That area of the retina encompassed by the
  temporal arcade of vessels, which corresponds to
  the center of vision

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Age Related Macular Degeneration

• Normal aging changes in the macula
• Photoreceptors reduced in density and
  distribution
• Ultrastructural changes in the retinal pigment
  epithelium (RPE)
• Basal laminar deposits of the RPE
• Progressive vascular involutional changes in the
  choriocapillaris

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Age Related Macular Degeneration
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Age Related Macular Degeneration

• Dry ARMD
• Drusen
• Pigmentary changes
• Atrophy
• Drusen are the most common and earliest finding
  in dry ARMD
• The metabolic byproducts of RPE cell metabolism
• Serve as a marker of non-exudative ARMD

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Age Related Macular Degeneration

• Vary in shape, size and color
• Hard drusen
• Soft drusen
• Manifest as focal yellow-white deposits deep to
  the RPE
• Drusen associated with overlying pigmentary
  changes from photoreceptor dysfunction or RPE
  demise

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Age Related Macular Degeneration

• Progressive RPE disruption leads to loss of
  overlying sensory retina and underlying
  choriocapillaris
• Results in localized atrophic regions that extend
  and coalesce on and around the fovea

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Age Related Macular Degeneration

• Wet ARMD
• Vascular changes
• Fluid under sensory retina and RPE
• Choroidal neovascular membrane (CNV) formation
  and RPE detachment
• May see subretinal hemorrhage or fluid with CNV
• Progression to endstage disciform macular
  scarring

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Age Related Macular Degeneration

• Vessels of the CNV membrane originate from the
  normal choriocapillaris and enter the subretinal
  space

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ARMD

• How does ARMD cause vision loss?
• permanent alterations in sensory retina, RPE and
  choroid within the macula
• Disciform scarring or atrophy in areas where
  retina ceases to exist

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Age Related Macular Degeneration

• Evaluation of ARMD
• Amsler Grid
• Document central or paracentral scotoma
• Useful as a home screening tool to note any acute
  changes in vision

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Age Related Macular Degeneration

• Ophthalmoscopy
• Direct
• Slit Lamp
• Indirect
• Note gross geographic, vascular and exudative
  ghanges

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Age Related Macular Degeneration

• Fluorescein Angiography to identify and localize
  any abnormal vascular processes like areas of
  nonperfusion and choroidal neovascularization

Early
Middle
Late
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Age Related Macular Degeneration
An optical coherence tomography image can
distinguish between the various types of retinal
pigment epithelium detachments, quantify the
extent of retinal thickening, and image choroidal
neovascular membranes in the subretinal space.
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Age Related Macular Degeneration

• Prophylaxis
• Multivitamins high in Lutein and Zeaxanthine
  (which are photoprotective macular pigments) and
  antioxidants like Vit C, Vit E, ?-Carotene, and
  Zinc oxide
• Sunglasses to block UV light

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Age Related Macular Degeneration

• Treatment
• At this time no medical management available
  beyond prophylactic therapy with multivitamins
• Currently, investigations geared towards
  compounds with anti-angiogenic properties
  (a-Interferon, Thalidomide, and inhibitors of
  VEGF)

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Age Related Macular Degeneration

• Photodynamic Therapy for wet ARMD
• IV administration of a porphyrin-based med, which
  is absorbed by abnormal subretinal vessels
• Porphyrin-based med is activated by a low-energy,
  non-thermal infrared laser exposure
• Causes localized vascular damage, but spares
  overlying retina
• Laser photocoagulation may also be applied in
  extra-foveal regions

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Age Related Macular Degeneration

• Submacular Surgery
• Removal of choroidal neovascular membranes
• Removal ofd submacular hemorrhage

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Retinopathy of Prematurity

• Vasoproliferative retinal disease that affects
  premature infants
• Birth weight lt 1500g
• Gestational Age lt 32 wk
• Risk is 3X greater for infants less than 1 kg
  than for those that are 1 to 1.5 kg
• Infants born at 23 to 27 weeks gestation have a
  very high chance of developing ROP

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Retinopathy of Prematurity

• Two phases
• Acute ? stunted development of normal vessels in
  peripheral retina, with abnormal proliferation of
  vessels and fibrous tissue
• Chronic/Late ? retinal detachment, macular
  ectopia, and severe visual loss
• More than 90 of cases of acute ROP go on to
  spontaneous regression

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Retinopathy of Prematurity

• Screening (ACOG and AAP guidelines)
• All infants weighing less than 1250g
• All infants requiring oxygen in excess of room
  air in the first 7 days of life
• Infants at particularly high risk are those with
  birth weights less than 1000g and gestational
  ages less than 27 weeks
• First eye exam 4-6 weeks after birth
• Follow-up schedule depends on the progression or
  regression of the disease

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Retinopathy of Prematurity

• Classification
• Location
• Zone I (inner)
• Zone II (mid-peripheral)
• Zone III (peripheral)
• Severity
• Stage 1
• Stage 2
• Stage 3
• Stage 4
• Stage 5

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Retinopathy of Prematurity

• Stage 1
• Demarcation line
• Thin but definite structure that separate
  avascular retina anteriorly from the vascularized
  retina posteriorly
• Abnormal branching of vessels up to the line
• Line is flat, white, and in the plane of the
  retina

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Retinopathy of Prematurity

• Stage 2
• Ridge
• Demarcation line of stage 1 has height and width,
  occupying a volume extending out of plane of
  retina
• Small tufts of new vessels on surface retina
  postrior to ridge

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Retinopathy of Prematurity

• Stage 3
• Ridge with extraretinal fibrovascular
  proliferation

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Retinopathy of Prematurity

• Stage 4
• 4A ? Subtotal retinal dteachment that does not
  involve central macula
• 4B ? Subtotal retinal dteachment that involves
  central macula

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Retinopathy of Prematurity

• Stage 5
• Total retinal detachment
• Funnel shaped, but may have an open or closed
  configuration in anterior or posterior areas

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Retinopathy of Prematurity

• Plus Disease
• Retinal venous dilation and arterial tortuosity
  in the posterior pole
• Iris vascular engorgement and pupillary rigidity
• Graded as mild, moderate, or severe
• Indicative of progressive vascular incompetence,
  and a strong risk factor for development of more
  severe ROP

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Retinopathy of Prematurity

• Treatment
• Since 90 of infants with ROP undergo spontaneous
  regression, treatment is only performed on those
  infants with high risk of developing retinal
  detachment
• Threshold Disease ? defined by the Cryo-ROP Study
  as the level of disease at which 50 of infants
  are predicted to go blind without treatment
• Criteria at least five contiguous or eight
  cumulative clock hours of stage 3 ROP in zones I
  or II in the presence of Plus disease

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Retinopathy of Prematurity

• Cryotherapy
• Applied to the avascular anterior retina
• Reduced the incidence of an unfavorable outcome
  (eg, macular dragging, retinal detachment) by 50
• Laser Photocoagulation
• Also applied to the avascular anterior retina
• Less traumatic than cryo
• More cost-efective

• Cryotherapy to the anterior avascular retina in
  an eye with threshold ROP

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Retinopathy of Prematurity

• Surgical reattachment for stages 4 and 5 ROP
• Only 10 of these patients will have ambulatory
  vision
• Surgical intervention in stage 4A has more
  favorable prognosis than stage 4B or stage 5

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Amblyopia

• Definition
• Poor visual function in one or both eyes that
  results from inadequate or abnormal stimulation
  of the visual system during a critical early
  period of development
• Estimated prevalence in USA is 2-5
• Visual system, particularly the visual cortex in
  the CNS, is not complete at birth but continues
  to develop until 6 years of age
• Remains quite plastic during this period, and
  normal development depends on normal visual
  experience
• Amblyopia uniquely occurs during childhood, but
  effects may be permanent if not adequately
  treated
• After the critical period, the visual system is
  no longer vulnerable to amblyopia
• It is difficult, if not impossible, to treat
  amblyopia successfully after the critical period
  has passed

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Amblyopia

• Important to differentiate amblyopia from the
  peripheral abnormalities which cause it
• Strabismus
• Malalignment of the visual axes of the eyes
• Optical defocus
• Significant assymetry of refractive error, or
  severe bilateral refractive error
• Pattern or form deprivation
• Lesions that obstruct the visual axis, suchas
  cngenital cataract, vitreoous hemorrhage, ptosis,
  or corneal opacity
• Congenital or organic abnormality
• Congenital lesion of the visual pathways, such as
  a macular scar or coloboma

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Amblyopia

• Strabismus
• Both eyes cannot be used simultaneously w/o
  visual confusion or double vision
• One eye preferentially used for fixation
• Other eye chronically suppressed to avoid
  diplopia, and can become amblyopic

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Amblyopia

• Congenital Catarct
• Common causes
• Familial inheritance
• Intrauterine infection (eg, Rubella)
• Metabolic diseases (eg, galactosemia)
• Chromosomal abnormalities
• 1 out of every 2000 live births
• Posterior polar cataracts tend to produce more
  visual impairment than do other types

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Amblyopia

• Steps in the treatment of amblyopia
• Identify underlying cause
• Removal of any obstruction of visual axis if
  present (eg, congenital cataract, vitreous
  hemorrhage)
• Correction of any significant refractive error
• Patching
• Method of reversing amblyopia by forcing use of
  the eye with poorer vision so that it may develp
  normal visual pathways
• Rule-of-thumb full-time patching of the sound
  eye for one week per year of life
• Risk induction of occlusion amblyopia
• Alternatives to patching Penalization or
  Transluscent Filters
• Terminate amblyopia treatment when the trated eye
  has a level of acuity equal to the sound eye

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Amblyopia

• Can the vision of an amblyopic eye ever improve
  in adulthood?
• Reports of significant improvements in amblyopic
  eyes after the critical period has passed when
  the sound eye is lost (eg, enucleation)
• Important predictor of the extent of visual
  improvement is the presence of central fixation
  in the amblyopic eye prior to the loss of the
  sound eye

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Pathologies Affecting Visual Fields

• Primary Open Angle Glaucoma
• Chronic progressive optic neuropathy
• Elevated intraocular pressure (gt 21 mmHg)
• Visual field loss
• Adult onset
• Prevalence 1.86 of US population (2.22 million
  people)

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Pathologies Affecting Visual Fields

• Lesions of the Central Nervous System
• Optic Nerve
• Optic Chiasm
• Optic Tracts
• Optic Radiations
• Occipital (Visual) Cortex

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Pathologies Affecting Visual Fields

• Pituitary Adenoma

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Pathologies Affecting Visual Fields

• Optic Nerve Sheath Meningioma

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Visual Field Testing

• Confrontation Visual Fields

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Visual Field Testing

• Kinetic Perimetry
• Presentation of a moving stimulus of known
  intensity from a non-seeing area to a seeing area
  until it is perceived
• Moved along various meridians, and points of
  perception recorded on a chart
• Advantage Relaiability, measures entire visual
  field
• Disadvantage Time consuming

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Visual Field Testing

• Kinetic Perimetry
• Join the points along different meridians for a
  given stimulus intensity to plot out an isopter
• Plot out multiple isopters for different
  intensities of light to create a contour map of
  the visual field

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Visual Field Testing

• Static Perimetry
• Assess the differential light sensitivity of a
  predetermined area of the visual field
• Non-moving stimuli of varying intensity

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Visual Field Testing

• Static Perimetry
• Measures the threshold of light perceprion at a
  given point in the visual field, which may
  correspond to local retinal or optic nerve damage
• Advantage automatic, fast
• Disadvantage less reliable, smaller field

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Visual Field Testing