LV - Low Vision Conditions - Week 9 Flashcards
Can pigment change without drusen be considered AMD? Is there a significant risk of progression to late AMD?
No
-no significant risk of progression
Define the following classifications of AMD
Normal ageing changes
Early AMD
Intermediate AMD
Late AMD
Normal ageing changes - only druplets and no AMD pigmentary changes
Early AMD - medium drusen and no AMD pigmentary abnormalities
Intermediate AMD - large drusen and/or any AMD pigmentary abnormalities
Late AMD - neovascular AMD and/or geographic atrophy
-within 2DD of the fovea in either eye
What kind of advice can be given to all AMD patients (2)?
Stop smoking if they do so
Self-monitor with amsler
What is the treatment for atrophic AMD?
None available
What is the treatment for neovascular AMD (3)? Note the costs and whether or not they are TGA approved for AMD.
Anti-angiogenesis therapies
-lucentis (ranibizzumab) - more expensive
-avastin (not TGA approved for AMD) - less expensive
Eyelea (aflibercept) - same cost as lucentis but better half-life
Describe the effectiveness of lucentis for AMD treatment. Compare it to avastin and eyelea.
After 24 months of monthly lucentis injections, visual acuity stabilises or improves in 90% of patients
-reduces retinal thickness
-promotes resoprtion of fluid
Studies have found similar effectiveness with avastin
Eyelea injected every 2 months was found to be similar to avastin and lucentis as well
What do studies suggest of the effectiveness of vitamin and mineral supplements? For which severities of AMD are of particular note?
AREDS supplements were found to reduce the risk of moderate visual loss among some patients with AMD
List the components of AREDS supplements (5). Compare it to AREDSII.
Beta-carotene
Vitamin C
Vitamin E
Zinc oxide
Cupric oxide
AREDSII removed beta-carotene, zince lowered
Role of lutein, zeaxanthin, and long chain polyunsaturated fatty acids
List some foods rich in lutein and xeaxanthin antioxidants.
Spinach
Silver beet
Corn
Capsicum
Peas
pumpkin
Brussels sprouts
Broccoli
List some fish rich in omega-3.
Salmon
Mackerel
Anchovies
Trout
List some foods rich in vitamin E.
Nuts
Whole grains
List some foods rich in zinc.
Oysters
Seafood
Nuts
Legumes
List some foods rich in selenium.
Nuts, especially brazil nuts
What is the incidence of fellow eye involvement during the first two years of AMD? What about five years after that?
28-36%
6-12% for the five years after
Is useful peripheral vision maintained indefinitely with AMD?
Yes, never will go black blind
What level of visual acuity loss can be expected with exudative and non-exudative AMD and what effect does antiVEGF treatment have?
Non-exudative - to about 6/120
Exudative - can be worse than 6/120
AntiVEGF can hold vision at the level it was when treatment started
What kind VF defects do you expect to see in those with AMD (2)?
Central or paracentral scotoma with normal periphery
What would symptom would you expect of AMD patients related to near work?
Difficulty reading
What would symptom would you expect of AMD patients related to distance work (3)?
Loss of detail in distance
Difficulty recognising faces
Television difficulties
What is colour vision like with AMD?
Decreased
Do AMD patients tend to struggle with mobility?
Generally no, mobility is fair even in advanced cases
What visual hallucination is common with AMD and what is generally required for this to occur? Note percentage of cases among AMD patients.
Charles bonnet syndrome
-requires low bilateral visual acuity
-10 to 25% of patients with macular degeneration report it
How do individuals with AMD tend to view things and why?
Eccentrically view because of the central scotoma
-some people automatically develop this technique, others do not, while some dont adopt the best eccentric viewing position
List distance low vision management options for AMD patients. List 3 for glare.
Distance
-magnification
-telescopes
-decreased viewing distance (closer, larger screen)
Glare
-UV shields
-tinted lenses
-hat with brim
What is the management for charles bonnet syndrome?
Advice and reassurance
Can eccentric viewing be trained? Explain.
Yes, but benefits are controversial
Good for enhancing awareness of scotoma
What often precedes progression to late AMD and what form?
Spontaneous drusen regression
-geographic atrophy
Briefly describe retinitis pigmentosa.
Rod-cone dystrophies that represent an inherited group of disorders characterised by progressive visual field loss and night blindness
What mode of inheritence do majority of retinitis pigmentosa forms have?
Autosomal recessive
What occurs in retinitis pigmentosa?
Progressive atrophy of rods and cones
Which modes of inheritence of retinitis pigmentosa have the worst prognosis (2)?
X-linked and autosomal recessive
What causes the bony spicule appearance in retinitis pigmentosa?
Migration of pigment into neural retina
How do arterioles appear in retinitis pigmentosa? What about the ONH?
Attenuated
ONH has waxy pallor
What can be expected of dark adaptation on first presentation in patients with retinitis pigmentosa?
They present with defective dark adaptation
What are the first posterior signs of retinitis pigmentosa you expect to see (3)?
Arteriolar narrowing
Fine dust-like intra-retinal pigmentation
Loss of pigment from RPE
What are mid-stage posterior signs of retinitis pigmentosa you expect to see (1) and where first?
More pigmentary changes
with a perivascular bone-spicule configuration seen initially in the midperiphery
What eventually occurs with retinitis pigmentosa?
Pigment spreads both posteriorly and anteriorly
Describe what happens to visual fields as retinitis pigmentosa progresses.
Contraction of the visual field ultimately leaving a tiny island of central vision
When does the optic nerve begin to take on a waxt pallor with retinitis pigmentosa? Is VA typically good? Explain.
When visual fields are significantly affected, is around the time the optic nerve head looks waxy
VA is generally good until this later stage
What typically occurs after visual fields are significantly contracted with retinitis pigmentosa? Why does this occur and what can be said of the arterioles and ONH appearance?
Unmasking of larger choroidal blood vessels give the fundus a tessellated appearance
Severe aerteriolar attenuation
Marked optic disc pallor
List 6 associated ocular findings that may be present alongside retinitis pigmentosa.
Maculopathy
-atrophic or cystoid macular oedema
Cataract
-posterior subcapsular
Myopia
Optic disc drusen
Open agle glaucoma
Keratoconus
What do you expect to see on electroretinogram of retinitis pigmentosa? What about early stages?
Abnormal, even early stages
What is dark adaptation like in retinitis pigmentosa? What happens to the threshold and what can be said of the rod-cone break?
Delayed
Elevation of dark adaptation threshold
Absence of rod-cone break
Describe the range of vision that individuals with retinitis pigmentosa may have.
6/6 to NLP
Describe what vision is usually like with retinitis pigmentosa (prognosis).
Typically good until late stages
-unless associated conditions like cataract or maculopathy
What kind of decline do you expect to see on visual fields of retinitis pigmentosa? Where does decline begin and which region is more often abnormal?
Exponential
-approx 5% per year
Begins in the mid-periphery
Often superior visual field abnormal
Is visual field loss symmetrical between the eyes in retinitis pigmentosa?
Yes
List two common syndromes associated with retinitis pigmentosa. Note what each is characterised by.
Ushers syndrome
-characterised by congenital profound deafness
Laurence-moon-biedl syndrome
-characterised by RP, intellectual impairment, polydactyly, obesity, hypogenitalism
What is the treatment for retinitis pigmentosa?
None at present
-future treatments are likely to come from genetic therapy or retinal transplants
Describe the prognosis for retinitis pigmentosa for each of the following modes of inheritence
X-linked
Autosomal recessive
Autosomal dominant
X-linked - blindness may occur by fifth decade
Autosomal recessive - blindness may occur by sixth or seventh decade
Autosomal dominant - blindness may occur by eighth decade
Do patients with retinitis pigmentosa often have difficulty with mobility symptoms?
Yes, particularly at night
Do patients with retinitis pigmentosa often struggle with glare?
Yes
Does retinitis pigmentosa affect colour vision?
Yes, in the late stages it decreases
What effect does having peripheral constrictions have on the benefits of magnification as a low vision aid for patients with retinitis pigmentosa?
Limits the benefit, better to use hand magnifier away from the eye where the field area is larger
What can be done to aid mobility in individuals with retinitis pigmentosa (5)?
Reverse telescopes or concave lenses for scanning
Scanning strategies
Guide dogs
Canes
Wide angle torches for low light levels
Does cataract affect colour vision?
Yes, faded
Give some examples of low vision aids for individuals with cataracts (3).
Magnification
Telescopes and magnifiers
Focal illumination for near tasks
List four conditions in children that may contribute to them having low vision. What is one thing to keep in mind with children and low vision?
Albinism
Retinopathy of prematurity
Stargardts
Congenital nystagmus
Children have accommodation - allows even children with 6/120 vision to manage with little magnification assistance
