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38 Cards in this Set
- Front
- Back
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What is a dystrophy? |
A hereditary disorder; disruption in the function of a particular structure or tissue Function modified when abnormal gene switched on. Abnormal gene modifies one of the metabolic pathways of the tissue, – results in abnormal nutrition and tissue degeneration |
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What is the general effect of a choroidal or retinal dystrophy? |
Typically affect the retinal pigment epithelium photoreceptors or the choriocapillaris Usually bilateral and symmetrical Frequently associated with myopia and cataracts |
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What is in involved in optometric investigation? |
• Full symptoms & history – Family history • Visual acuity • Pupil reactions • Visual fields – Amsler charts • Colour vision assessment • Dilated fundus examination |
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What are the photoreceptor /RPE cell complex dystrophies? |
• Retinitis Pigmentosa (RP) dystrophies – Purely ocular RP – Usher’s syndrome – Laurence-Moon Bardet-Biedl syndrome • Leber’s amaurosis • Stationary night blindness • Cone dystrophies |
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What is retinitis pigmentosa? |
• A group of diseases with the common features – Pigmentary retinal degeneration – Nyctalopia (night blindness) – Visual field defects • Progressive loss of photoreceptor (mainly rod) and RPE function - receptor/RPE cell metabolic complex affected • Overall prevalence about 1 in about 5,000 • Most common hereditary retinal dystrophy |
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What are the symptoms of retinitis pigmentosa? |
• Night blindness • Slow dark adaptation • Reduced peripheral field • Photopsia • Central visual loss late feature – Loss of cones – But cataract may affect it earlier |
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What are the signs of retinitis pigmentosa? |
• Loss of contrast sensitivity – 1st • Visual acuity normal • Bilateral intraretinal mid-peripheral pigmentary changes • RPE atrophy • Tesselated fundus • Arterial attenuation • Optic disc pallor • Atrophy at the macula • Epiretinal membrane • Cystoid macula oedema |
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How is visual function affected in RP? |
• Progressive field defect – Partial or complete ring scotoma ~40-50° – Concentric reduction – Central island of vision -> May be lost as well • Colour Vision – Acquired type 3 (tritan) colour deficiency • Nyctalopia |
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What are the symptoms of X-linked R.P.? |
Severe night blindness, photophopia, mobility problems due to constricted field, ↓VA |
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What are the ocular associations of retinal dystrophies? |
• Posterior sub-capsular cataract • Open-angle glaucoma • Myopia • Keratoconus • Vitreous changes – PVD – Uveitis • Optic disc drusen |
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What is usher’s syndrome? |
Deafness and visual impairment |
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What is Bardet-Biedl Syndrome? |
• Retinitis pigentosa combined with – Polydactly – Severe learning difficulties – Bull’s eye maculopathy – 80% have severe retinal changes by the age of 20 years |
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What is Leber’s Congenital Amaurosis? |
The earliest and most severe retinal dystrophy resulting in blindness in infancy. |
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What are the clinical findings of Leber’s Congenital Amaurosis (LCA)? |
• Peripheral pigment stippling, vessel attenuation, hypoplastic disc, wrinkled internal limiting membrane • Leads to depigmentation, diffuse atrophy, multifocal pigmentary lesions at the posterior pole • Pupillary light reflex absent |
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What are the two clinical forms of Leber’s Congenital Amaurosis (LCA)? |
• Congenital or complicated: – Visual impairment at 3 - 5 months – Photophobia, nystagmus – Poor pupil responses – Blindness in 1st year – Often fatal due to systemic complications • Juvenile or Uncomplicated: – Poor vision falling to 6/60 with nystagmus at 10 years – Hypermetropia and cataract in 50% – Retina initially normal - similar to RP by ~3yrs |
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What is stationary night blindness? |
Congenital nyctalopia |
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What are the signs of stationary night blindness? |
• Normal fundus appearance or fundus albipunctatus (small white dots over whole retina) • VA generally normal |
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What May stationary night blindness be associated with? |
May be associated with myopia |
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What is more common, rod dystrophies or rod dystrophies? |
Rod dystrophies are more common, cone dystrophies are less common |
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What are the symptoms and signs of a cone or rod dystrophy? |
– Poor VA, photophobia, poor colour vision and nystagmus • Characteristic “Bull’s eye” maculopathy – Hyperpigmentation surrounded by rings of hypo and hyper • VA < 6/60, central field loss |
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What are the symptoms and signs of a cone or rod dystrophy? |
• Poor VA, photophobia, poor colour vision and nystagmus • Characteristic “Bull’s eye” maculopathy – Hyperpigmentation surrounded by rings of hypo and hyper • VA < 6/60, central field loss |
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What is the ocular effect of batten’s disease? |
Blindness |
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What is the ocular effect of batten’s disease? |
Lipopigments accumulate in neural, visceral and somatic tissue resulting in seizures, psychomotor deterioration and blindness. Can be fatal. |
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Give three Retinal Pigment Epithelial Dystrophies? |
• Stargardt’s disease complex (fundus flavimaculatus) • Vitelliform dystrophies (Best disease) • Familial dominant drusen |
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How can Stargardt’s Disease Complex be identified? |
• Different types share common feature of yellow, concentric, sub-retinal flecks which stain with fluorescein – Similar to drusen but triangular • Macular atrophy common – Reduced visual acuity |
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How can Stargardt’s Disease Complex be identified? |
• Different types share common feature of yellow, concentric, sub-retinal flecks which stain with fluorescein – Similar to drusen but triangular • Macular atrophy common – Reduced visual acuity |
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What is the clinical course of stargardt’s disease? |
• Pigmentary macular degeneration • Peripheral subretinal flecks - enlarged RPE cells filled with lipofuscin-like material • Progressive diffuse atrophy of the RPE |
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What is the significance of Fundus AutoFluorescence (FAF)? |
These photos may reveal the presence of lipofuscin deposit |
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How is visual function affected in Stargardt’s disease? |
• Colour vision : early onset of Type 1 red / green acquired deficiency similar to a congenital protan • Visual acuity – Reduced in the 2nd decade – Severe progressive loss of VA - CF in the 4th decade. • Visual fields : central scotoma |
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How is visual function affected in Stargardt’s disease? |
• Colour vision : early onset of Type 1 red / green acquired deficiency similar to a congenital protan • Visual acuity – Reduced in the 2nd decade – Severe progressive loss of VA - CF in the 4th decade. • Visual fields : central scotoma |
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What is the inheritance of Best Vitelliform Macular Dystrophy? |
Inheritance: autosomal dominant |
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How common is Best Vitelliform Macular Dystrophy? |
Second most common maclula dystrophy |
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How common is Best Vitelliform Macular Dystrophy? |
Second most common macula dystrophy |
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What is Best Vitelliform Macular Dystrophy? |
• Accumulation of yellow material beneath retina and RPE (esp. macula) • “Egg yoke” pattern at macula |
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What are the ocular effects of Best Vitelliform Macular Dystrophy? |
Atrophy of the RPE and disciform degeneration finally result with profound loss of VA. |
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What is the prevalence of stargardt’s disease complex? |
• Prevalence : 1 in 10,000 |
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What is the inheritance of stargardt’s disease complex? |
Autosomal recessive (or dominant) |
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What is the inheritance of familial dominant drusen? |
Autosomal dominant |
