what is the size of half a central retinal vein width (as it emerges from the disc)
63 micrometers
risk factors for AMD (NICE guidelines)
- Diet low in omega 3 and 6 and cartenoids and minerals is a risk of AMD
- Lack of exercise
- Smoking – biggest
- Older age
- Hypertension
- Family history of AMD
- BMI of 30 kg/m2 or higher
- Presence of AMD in the other eye
- High fat diet
AMD dry tx
- No treatment available
- Advise on lifestyle modifications eg smoker
- Advise patients on nutritional supplements
- Educate about symptoms of progression and self-monitoring eg with amsler
- Aim: to slow down the progression
- NICE doesn’t say much about supplements, since mixed and depends on the px
when is it classified as normal when there is drusen present (i.e no AMD)
no sign of AMD
small hard drusen (<63 micrometers only)
these patients do not have AMD
classification of low risk of progression early AMD
- Medium drusen (≥63 but <125 micrometres), OR
- Pigmentary abnormalities.
(not both together)
classification of medium risk of progression early AMD
- Large drusen (≥125 micrometres), OR
- Reticular drusen, OR
- Medium drusen with pigmentary abnormalities.
classification of high risk of progression early AMD
- Large drusen (≥125 micrometres, bigger than vein width) with pigmentary abnormalities, or
- Reticular drusen with pigmentary abnormalities, or
- Vitelliform lesion without significant visual loss (best-corrected acuity better than 6/18), or
- Atrophy <175 micrometres and not involving the fovea
classification of late dry AMD
- Geographic atrophy (in the absence of neovascular AMD).
- Significant visual loss (6/18 or worse) associated with:
- Dense or confluent drusen (drusen joining together), or
- Advanced pigmentary changes and/or atrophy, or
- Vitelliform lesion.
what are drusen
Drusen are sub retinal pigment epithelium deposits of extracellular debris composed of lipids and proteins which sit just below the RPE, or between the RPE and bruchs membrane
what are reticular drusen and what are they also called
Reticular drusen are also known as pseudo-drusen or subretinal drusenoid deposits. Contrary to the drusen which lie below the retinal pigment epithelium (RPE), reticular drusen are located superficial to the RPE, slightly superior to RPE. They are yellowish subretinal lesions arranged in a network and indicate a greater risk of AMD progression.
Retiucular drusen more pale and yellow
what are Vitelliform Lesion, dry AMD
Accumulation of lipofuscin within the subretinal space – causes hyper reflective lesions
dry AMD, atrophy what is it
Geographic atrophy - loss of cells in the fovea - rpe and outer retina (rods and cones are lost). Complete loss or rpe and outer retina if is at least 250 microns wide - can be seen on any OCT- standard research definition
Atrophy – appears as disease progresses in AMD, early stages might be small patches,
RPE absent then choroid is brighter in OCT scan.
dry AMD role of the optometrist
- Make the diagnosis.
- Give relevant advice (including advice on driving and smoking cessation)
- Counselling – diagnosis is often a shock
- Provide Information – needs to be accessible (e.g. large print)
- Monitor – disease progression
- Referral
- Low Vision Services
- For SI or SSI Registration (Ophthalmology)
- To Social Services
management of dry AMD
- No treatment available
- Advise on lifestyle modifications eg smoker
- Advise patients on nutritional supplements
- Educate about symptoms of progression and self-monitoring eg with amsler
- Aim: to slow down the progression
- NICE doesn’t say much about supplements, since mixed and depends on the px
what are the emerging tx in USA
- Complement Factor inhibitors
- FDA approved
- Intravitreal injections
- Monthly or bimonthly
- Utility has been shown in patients with severe dry AMD (Geographic atrophy)
- Likely that geographic atrophy away from the foveal centre will be treated first as this is most beneficial to preserve vision by slowing rate of growth of geographic atrophy
Nutritional supplements AREDS (age related eye disease study) what is it
Large scale, randomized, double-masked, placebo- controlled clinical trial (RCT)
Looked at effectivity of supplements in delaying preventing onset progression of AMD
AREDS and AREDS 2 – Outcomes
antioxidant supplements reduced the risk of AMD progression in those with moderate/ high risk of progression formulation from AREDS 2 study,
- since ARED1 study contained Beta-carotene which is associated with increased risk of lung cancer in smokers so Lutein and Zeaxanthin instead (all new supplements do not ahve beta carotene anymore)
But, a systematic review showed that supplements had no effect in the prevention of AMD
Omega-3 fatty acids may help prevent AMD
Vitamin E and Betacartoene are associated with increased mortality
what was administered in AREDs 2 study
AREDS 2 - Multicenter, randomized, double-masked, placebo-controlled clinical trial to evaluate
* Placebo,
* Lutein (10 mg)/zeaxanthin (2 mg),
* Omega 3 fatty acids (DHA 350 mg and EPA 650 mg), and
* Lutein/ Zeaxanthin and Omega-3 fatty acids combination
In addition, participants were administered either
* the original AREDS formulation (vitamins C, E, and beta-carotene, and zinc with copper) or
* some modification of the AREDS formulation (either elimination of beta-carotene, lowering of the zinc, or the combination of the two)
smoking cessation in AMD
Smoking increases oxidative stress
Second most important risk factor (after age)
Most important modifiable risk factor
Smoking
Slows down choroidal blood flow
Promotes ischemia
Reduces macular pigment
other lifestyle modifications in AMD
Increased physical activity > No direct evidence
Reduced alcohol consumption > Unclear whether moderate consumption is a risk
Reduction of waist-hip ratio > Especially in obese – unclear?
Diet rich in omega-3 polyunsaturated fatty acids > Evidence for decreased risk
when do we refer px’s with dry amd to hes
for certification of sight impairment or low vision services
new symptoms that may suggest late AMD (wet active)
to participate in research for new tx options
benefits of registration for sight impairment
- National Entitlement Card (NEC)
- Scottish National Blind Persons Scheme
- Disabled Persons Railcard
- TV Licence discount
- Blue Badge
what do rehabilition clinics do
- Rehabilitation based on adaptation to vision loss
- Advise on low vision services
- Support patients in dealing with visual impairment
- Direct to suitable information, e.g. Macular Society
reasons for referral to social services
- RNIB
- Eye Care Liaison Officer
- Virtual or in person
- Discuss diagnosis and assess needs
- Macular Society
- Sight loss and depression are linked
- The prevalence rates of depression in elderly populations with sight loss are between 25 per cent and 45 per cent.
- The relative risk of depression is estimated to be around 3.5 times higher for those with sight loss compared to those fully sighted.
- It is estimated that up to 30 per cent of those living with age related macular degeneration experience moderate to severe depressive symptoms due to vision loss.
- Falls are a major cause of disability
- 1.7x higher in people with sight loss
- 47% of falls in low vision patients are due to their sight loss
- The cost to NHS of falls associated with sight loss in Scotland is at least £1million per annum.
