BASICS

DESCRIPTION

• Age-related macular degeneration (AMD) is a leading cause of irreversible blindness among older patients in the developed world (1)

– AMD is the leading cause of legal blindness in patients ≥65 years in the US

– 90% of AMD patients have the non-exudative or “dry” form

– 10% have the exudative or “wet” form

• Polypoidal choroidal vasculopathy (PCV) is a separate disease from AMD, characterized by abnormalities in the inner choroid, external to the choriocapillaris, including a branching network of dilated vessels that leads to serous leakage and hemorrhage.

– PCV predominately affects patients of African and African American descent and Asian patients, with a lower incidence in Caucasians

EPIDEMIOLOGY

Incidence

• Overall 5-year incidence of late AMD was 0.9% (2)

• Incidence of Early AMD increased from 3.9% in patients aged between 43–54 years to 22.8% in patients >75 years (2)

• No clear incidence data available for PCV

Prevalence

• Total prevalence of any AMD in the 1991 civilian population ≥ 40 years was 9.2% (2)

• In the US, neovascular AMD and/or geographic atrophy in Americans 40 years and older is estimated to be 1.47% (2004 data) (1)

• PCV: Prevalence varies from 4–14%

– In Asians, men are more affected, usually unilaterally in the macula (3).

– Rates may be as high as 23–54% in Japanese patients diagnosed with AMD (3)

– In Caucasians, women are more affected bilaterally in the peripapillary region (3)

RISK FACTORS

• AMD

– Age

– Family history

– Race (Caucasians 5–6 times more frequently affected than African Americans)

– Cardiovascular risk factors including elevated cholesterol and hypertension

– Cigarette smoking

– Gender (women slightly more than men)

– Obesity

• PCV: Ethnicity and age

Genetics

• Genes associated with increased risk of AMD

– Complement Factor H (CFH) on 1q32

– Homozygosity for risk allele increases risk by factor of 7.4 (4)

– LOC 387715 on 10q26

– HTRA1 on 10q26

• Genes associated with increased risk of PCV

– LOC 387715 on 10q26

– HTRA1 on 10q26

GENERAL PREVENTION

• AMD

– Smoking cessation

– Age-related eye disease study (AREDS) vitamins for appropriate patients

25% decrease in progression to advanced AMD in high risk individuals (patients with intermediate or advanced AMD)

Vitamins include: Vitamins C&E, zinc, beta carotene, and copper

PATHOPHYSIOLOGY

• AMD most likely a combination of:

– Senescent retinal pigment epithelium (RPE) accumulates remnants of rod and cone membranes that leads to diminished RPE function and drusen formation

– Vascular theory proposes that choroidal circulation is diminished leading to retinal ischemia

– Genetic theory based on findings of AMD specific gene mutations

• PCV results from (5)

– Inner choroidal vasculature abnormalities (most common type)

– Polypoidal CNV, expanding rapidly under the RPE, ultimately with polypoidal lesions developing at vessel termini.

– Radiation associated choroidal neovasculopathy

COMMONLY ASSOCIATED CONDITIONS

• AMD

– HTN

– Elevated cholesterol

DIAGNOSIS

HISTORY

• AMD

– Central blurring, distortion, blind spot, or no symptoms (non-exudative)

• PCV: Central blurring, distortion, blind spot, or no symptoms

PHYSICAL EXAM

• AMD

– Findings in non-exudative AMD include drusen, retinal pigment epithelial changes, and retinal thinning/atrophy

– Findings in exudative AMD include vitreous hemorrhage, pigment epithelial detachment (PED), retinal and subretinal hemorrhage, lipid, fluid, and RPE tear

• Suspect PCV in an elderly patient with an exudative maculopathy and:

– Nonwhite patient

– Peripapillary CNV

– Few or no drusen in the fellow eye of a patient with unilateral involvement

DIAGNOSTIC TESTS & INTERPRETATION

Imaging

Initial approach

• AMD: Fluorescein angiography (FA) and optical coherence tomography (OCT)

• PCV: Indocyanine green angiography (ICG), FA, and OCT

Follow-up & special considerations

• AMD

– OCT to follow disease course and response to treatment

– FA as needed to help determine end points for treatment

• PCV

– OCT to follow disease course and response to treatment

– ICG and FA as needed to help determine end points for treatment

Diagnostic Procedures/Other

• AMD

– ICG

Pathological Findings

• AMD

– Non-exudative: Accumulation of rod and cone membranes leading to drusen, RPE pigment changes, and eventual retinal atrophy

– Exudative: Subretinal and Sub RPE choroidal neovascular membranes

• PCV pathology reveals (6):

– Large choroidal arterioles with an inner elastic layer

– Disruption of the inner elastic layer and arteriosclerotic changes of the vessels were identified by light microscopy.

– Transmission electron microscopy demonstrated increased deposition of basement membrane-like material, together with collagen fibers, in the arteriolar walls

DIFFERENTIAL DIAGNOSIS

• AMD and PCV:

– Degenerative myopia, angioid streaks, pattern dystrophies, presumed ocular histoplasmosis syndrome, multifocal choroiditis, serpiginous choroiditis, Best’s disease, Stargardt’s disease, gyrate atrophy, retinitis pigmentosa, choroidal rupture/trauma, idiopathic

TREATMENT

MEDICATION

First Line

• AMD

– Intravitreal anti-VEGF injections

Bevacizumab

Ranibizumab

• PCV:

– Conventional thermal laser for non subfoveal lesions

– Photodynamic therapy (PDT) for subfoveal lesions, based on the greatest linear dimension of the choroidal lesion seen on ICG

– Reduced fluence PDT may be useful in certain cases

– Intravitreal anti-VEGF injections, appear to be less effective than with AMD based on studies to date

– Combination therapy of anti-VEGF and PDT appears promising

Second Line

• AMD

– Intravitreal anti-VEGF injections: Macugen

– PDT based on the greatest linear dimension of the choroidal lesion seen on FA

– Conventional thermal laser for non-subfoveal lesions

– Intravitreal steroid injection

– Combination treatment

Combination of anti-VEGF +/– PDT +/– Intravitreal steroid

May be more useful in patients with poor response to treatment

ADDITIONAL TREATMENT

General Measures

• AMD

• AREDS vitamins

• Modifiable risk reduction: Control of HTN, high cholesterol, obesity (high Body mass index), and smoking cessation

Issues for Referral

Refer to retina specialist for evaluation and treatment of both AMD and PCV

SURGERY/OTHER PROCEDURES

• AMD

– Submacular surgery found to be less helpful in treating exudative AMD

ONGOING CARE

FOLLOW-UP RECOMMENDATIONS

• Retinal specialist

• Low vision evaluation for patients with vision loss

Patient Monitoring

• See follow-up

• Home Amsler Grid

DIET

• AMD

– AREDS nutrient supplementation for patients with intermediate or advanced AMD

– Balanced diet

– Omega-3 fatty acids, lutein, and zeaxanthin currently under investigation in AREDS II trial

PATIENT EDUCATION

AMD: http://www.aao.org/eyesmart/diseases/amd.cfm

PROGNOSIS

Normal lifespan, development, intelligence, and fertility

Pregnancy Considerations

• PCV: Concern for toxicity of PDT and anti-VEGF treatments in pregnancy

• AMD: Not applicable

COMPLICATIONS

AMD and PCV: Vision loss

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