Macular Degeneration a leading cause of Blindness:

Risk Factors, Symptoms, and Prevention

 

 

Macular degeneration is a common chronic eye disorder that causes blurred or reduced central vision or a blind spot in your visual field due to thinning of macula.

Age-related macular degeneration (AMD or ARMD), is a medical illness that is common among people over 50 years of age. It is a bilateral disease that is a leading cause of blindness in the western world. The macula is the part of the retina responsible for clear central vision in the direct line of sight. Early diagnosis and treatment of macular degeneration may help reduce vision loss and, in some cases, recover vision.

 

Macular degeneration is of 2 types

1. Dry macular degeneration: it is the most common type (90% of cases). It causes mild to a moderate gradual loss of vision over many years. It may first develop in one eye and then affect both. Over time the vision may worsen and affect the ability to do day to day activities such as read, drive and recognize faces.
2. Wet macular degeneration: It is the less common type but associated with a rapidly progressive loss of vision. Central vision may be completely lost within a few weeks. The wet type always starts in the beginning as a dry type.

 

Factors that may increase the risk include:

• Age: The disease is most common in people over 50 years of age.
• Race: It is more commonly seen in Caucasians.
• Smoking: Smoking cigarettes or being regularly exposed to smoke has been directly linked to increased risk of development of macular degeneration.
• Hereditary factors: Family history and genetics play a role in the development of the disease. Several genes have been identified that are related to the condition.
• Previous history of cardiovascular disease
• Obesity

Symptoms:

• Reduced central vision that may affect one or both eyes
• Distorted vision (metamorphopsia) such as a grid of straight lines appearing wavy or bent.
• Decreased intensity or brightness of colors
• Adapting to low light levels becomes increasingly difficult, such as when entering a dark room or a dimly lit restaurant.
• Increased blurriness of printed words or a general haziness in your overall vision or a well-defined blurry spot or a blind spot in your field of vision.
• Difficulty recognizing faces.

Dry macular degeneration can progress to wet (neovascular) macular degeneration, which is characterized by neovascularization (new blood vessels that grow under the retina and leak).

Macular degeneration doesn’t affect the peripheral vision, thus it rarely leads to total blindness.

 

How does the diagnosis take place?

• Drusen: It is the earliest detectable feature of ARMD. They are yellow white spots at the posterior pole. Drusen consists of focal aggregations of hyaline material located between the basal lamina of the RPE and inner collagenous layer of Bruch’s membrane. Drusen may be hard, soft, diffuse or calcified.
• Dry macular degeneration clinically appears as sharp circumscribed areas of RPE atrophy with varying degrees of loss of choriocapillaries.
• Wet macular degeneration is characterized by detachment of the RPE and choroidal neovascularization. (subretinal or choroidal neovascular membranes, SRNVM or CNVM)
• Amsler grid is used to test for defects in the central vision. In macular degeneration, the straight lines in the grid may look distorted, faded or broken.
• Fluorescein angiography
• Indocyanine green angiography
• Optical coherence tomography

What are the possible complications?

• Depression: People with macular degeneration affecting the central vision have a higher risk of developing depression and social isolation.
• Charles Bonnet syndrome: Visual hallucinations may develop in patients with profound loss of vision.

How to prevent it?

Having routine eye exams is very helpful to identify early signs. Following measures can be adopted to reduce the risk of developing macular degeneration:

• Antioxidants: Eating a diet rich in fruits and vegetables as they contain antioxidants, vitamins (vitamin C, beta carotene) and minerals (zinc, cupric oxide) that reduce the risk of developing macular degeneration.
• Quit smoking: Smoking cigarettes has been directly linked to increased risk of development
• Managing other medical conditions like cardiovascular disease or high blood pressure.
• Maintain a healthy weight and exercise regularly.