Rule 3

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Rule 3

• Jay C Bradley MD
• Sandra M Brown MD

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Case

• Chief Complaint left eye crosses
• HPI
• 18 month old healthy girl
• Left eye crossing intermittently for 4-5 mos
• More noticeable when tired
• Worsening overall
• PMH
• Normal pregnancy, delivery, development

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Family History
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Examination

• Normal visual attention for age
• Bruckner large superior crescents OU
• ITT
• One refixation OD
• No movement OS
• Motility
• Orthophoria at distance
• Orthotropia with 8-10 PD esophoria at near
• Versions full w/o oblique overaction

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• Penlight exam
• Normal OU
• Fundus exam
• Small optic nerves with indistinct borders OU
• Mild macular hypoplasia OU
• Lightly pigmented throughout
• Refraction
• 5.50 1.00 x 95 OD
• 6.00 1.00 x 90 OS

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Hereditary Optic Nerve Atrophy

• Bilateral gradual loss of central vision
• VA 20/40 to 20/100
• Long term prognosis rarely lt 20/200
• Generally starts in first decade
• Dyschromatopsia
• Ceocentral or paracentral scotomas with preserved
  peripheral field initially

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• Optic discs
• Temporal pallor
• Triangular temporal excavation
• Inheritance
• Usually autosomal dominant
• Occasionally autosomal recessive
• Phenotype varies by rate of vision loss

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• Browns Rules of Pediatric Ophthalmology
• 1 Dont make the child cry
• 2 Dont let the child make you cry
• 3 Everything in pediatric ophthalmology makes
  sense
• Lee Jampols Clinic Rule
• Try not to give the patient more than one disease

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• McCartneys Rule
• A patient may have as many diseases as they wish

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Albinism

• Foveal hypoplasia
• Critical clinical feature
• Iris transillumination defects
• Very difficult to detect in young kids
• Minimal fundus pigmentation
• Light-skinned
• Doesnt tan easily
• very light hair when young

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• Sensory nystagmus
• Foveal function in infancy lt 20/200 OU
• High hyperopia
• Accommodative esotropia
• Poor binocular stability
• Abnormal ganglion cell decussation
• Amblyopia

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Racial Differences

• Caucasians
• Tyrosinase gene mutations
• African Americans
• Intermediate phenotype
• P gene mutations

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Always on the Boards

• Chediak Higashi syndrome
• White cell dysfunction
• Recurrent infection
• Hermansky Pudlak syndrome
• Bleeding diathesis
• Increased frequency in Puerto Ricans

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Old Style Albinism Genetics
Type Location Locus Gene Product Function OC
A1 11q TYR Tyrosinase Enzyme OCA2
15q P P Protein Membrane OCA3
9q TYRP1 TYRP1 Enzyme OA1
Xp OA1 OA1 Protein Membrane HPS1
10q HPS1 HPS1
Protein Vesicle HPS2 5q ADTB3A
B-3A-adaptin Vesicle CHS1 1q CHS1
CHS1 Protein Vesicle
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New Thinking Phenotype Spectrum
Chalky white Acuity lt 20/200 Sensory nystagmus
Ordinary 20/30
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Leaky vs Non-Leaky Mutations

• Leaky mutations
• Some enzyme production
• Non-leaky mutations
• No enzyme production
• OCA-1B no activity chalk white
• OCA-1A partial activity darkens down
• Mom Dad net enzymatic deficiency

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Rule 3

• Better Fit Diagnosis Mild Albinism
• Fundus appearance
• Hyperopia
• Esotropia
• Family history
• pigmentation
• thick glasses high hyperopia
• Esotropia

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A Cruel Genetic Lottery

• Might our patient have inherited AD optic nerve
  atrophy too?
• Nothing rules it out.
• Watch for disc pallor
• Watch for decreased visual acuity resistant to
  refraction

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Albinism Treatments

• Glasses for refractive error
• UV protection medically indicated
• Patching for amblyopia
• Atropine must consider UV issues
• Surgery for residual esotropia
• Surgery for compensatory head turns
• Education about sunblock
• Education about genetics

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Can This Get Better on Its Own?

• YES!
• Subset of patients with seemingly total foveal
  hypoplasia at lt 1 yo
• Gradual production of foveal pigment over first 5
  years of life
• Nystagmus slows down, might stop
• Difficult to predict which kids will improve
• Clinical observation very smart kids

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The Amarillo Effect

• Many referrals for cant refract to 20/20
• Tow-headed kid and sibs/mom
• Mild foveal hypoplasia
• Normal light end of spectrum peripheral
  pigmentation for a Caucasian
• Mild to moderate hyperopia
• Not enough to cause bilateral amblyopia
• Especially boys