Definition
A.Macular degeneration (MD) is the result of age-related changes of the macula (central retina) that result in loss of central vision. MD is the leading cause of blindness in the United States.
Incidence
A.The risk of MD increases with age, with risk starting as early as age 50. It is estimated that MD will affect 2.95 million people by 2025. Currently, 25% of people 75 years of age have some degree of MD, and 14% of people older than the age of 84 years struggle with visual loss due to MD. With progressive MD in one eye, the opposite eye has greater than 40% risk of visual loss within 5 years.
Pathogenesis
A.There are two types of MD: Dry type and wet type:
1.Dry type is secondary to retinal atrophy. The initial cause of the atrophic changes is unclear.
2.Wet type is secondary to abnormal vascular growth in the subretinal space. Immune-mediated inflammation is believed to play a major role in MD.
Predisposing Factors
A.Age.
B.Smoking.
C.Family history.
D.Cardiovascular disease.
E.Dietary fat.
F.Cataract surgery.
G.Aspirin use.
H.Excessive alcohol intake (greater than three drinks per day).
I.White race.
J.Obesity.
Common Complaints
A.Gradual loss of vision in one or both eyes.
B.Scotoma (dark patch in the center of the visual field).
C.Distorted straight edges (appearing curved or irregular).
Potential Complications
A.Blindness resulting in functional impairments.
B.Depression secondary to visual loss.
C.Isolation.
Subjective Data
A.Review the onset, duration, and course of symptoms.
B.Was the change in vision sudden or gradual?
C.Ask if vision loss was unilateral or bilateral?
D.Was distance or near vision affected?
E.Determine family history of MD.
F.Review history of eye disorders and previous eye surgeries or treatments.
G.Review date of last eye exam, including dilation.
H.Review past medical history, including current medications.
I.Determine the amount of change in activities of daily living (ADL) due to visual impairment.
J.Ask about perceived safety concerns and history of falls.
Physical Examination
A.Vital signs, including blood pressure.
B.Inspect:
1.Symmetry of eyes and obvious deformities.
2.Pupil symmetry and response to light and accommodation.
3.Assessment of fields of vision and extraocular movements.
4.Funduscopic assessment observing for drusen bodies.
5.Snellen and Rosenbaum screening.
6.Observation of entropion or ectropion.
7.Observation of pterygium.
Diagnostics
A.Fluorescein angiogram (performed by an optometrist or ophthalmologist).
B.Optical coherence tomography (performed by an optometrist or ophthalmologist).
Differential Diagnosis
A.MD.
B.Presbyopia.
C.Cataracts.
D.Glaucoma.
E.Diabetic retinopathy.
Plan
A.General interventions:
1.Referral to eye specialist for formal diagnosis and prescription for corrective lenses.
2.Discussion of eye health, including routine eye exams and prevention of injury.
B.Patient teaching:
1.Prevention: Encourage a healthful diet of fruit, green leafy vegetables, fish, and nuts.
2.Discuss the importance of antioxidants, vitamin C 500 mg, vitamin E 400 IU, lutein 10 mg, zeaxanthin 1 mg, zinc oxide 80 mg, and copper (II) oxide. These supplements are thought to retard the progression of MD.
3.Stress the importance of routine eye exams.
4.Emphasize the need to control the blood sugar if diabetic and blood pressure if hypertensive.
5.Stress the importance of eye protection, including sunglasses.
6.Healthy lifestyle choices, including an active lifestyle and smoking avoidance, reduce the risk of MD.
C.Pharmaceutical therapy:
1.Ranibizumab or Aflibercept intravitreal injections may be used for treatment by the specialist.
Consultation/Referral
A.Referral to an optometrist or ophthalmologist is required for accurate diagnosis.
Individual Considerations
A.Adults:
1.Corrective lenses, additional visual aids, good lighting, and visual rehab should all be considered to reduce the functional impairments and isolation from MD.
2.Eye exams are covered, under certain circumstances, by Medicare. Patients can receive up-to-date coverage information at Medicare.gov.
B.Geriatrics:
1.The following link is a web-based age-related macular degeneration (AMD) update page, which emphasizes the geriatric’s point of view regarding AMD, and how practitioners may help meet patient needs and create shared-decision care plans: www.webrn-maculardegeneration.com.
2.Current research posited that use for at lease 3 months of anticholinergic medication was associated with an increase of AMD (as evidenced from a high Anticholinergic Burden Score). The suggested component contributing to primary lesions of AMD were the increase of amyloid-beta deposits from anticholinergic use.
3.Geriatrics that suffer with AMD have double the rate of depression compared to those without the disease. Evaluate for anxiety, depression, and quality of life issues every annual visit and
treat appropriately.
4.Review safety precautions with driving, ambulating, and within the home environment; and examine the ability to perform ADLs at home/work or activities such as shopping, sports, and so on.
5.Promote dietary modifications that research has suggested to prevent/improve AMD: beta carotene 15 mg, water-rich foods, vitamin C 500 mg, zinc oxide 80 mg, lutein 10 mg, and fish.
6.Vascular endothelial growth factor (VEGF) inhibitors (Avastin, Lucentis, and Macugen) decrease neovascularization; are monthly treatments; and might maintain vision for up to 2 years. Complications include uveitis, increased intraocular pressures, cataracts, and retinal detachment.