Wet ARMD can be treated quite effectively in the early stages with laser photocoagulation therapy. Photodynamic therapy using photosensitive drugs (verteporfin) and a low-powered laser ³ or low-dose radiation therapy are also alternatives.⁴ Antiangiogenics or anti−vascular endothelial growth factor (anti-VEGF) agents are also used. These drugs can cause regression of the abnormal blood vessels and improvement of vision when injected directly into the vitreous humor of the eye. The injections have to be repeated on a monthly or bimonthly basis. Examples of these agents include ranibizumab (Lucentis), bevacizumab (Avastin), and pegaptanib (Macugen).^1,²

Therapeutic Considerations

The primary treatment goal of the dry form and prevention of the wet form of ARMD involves the use of antioxidants and natural substances that correct the underlying pathophysiology—free radical damage and poor oxygenation of the macula. This can be accomplished by reducing the risk factors for ARMD by not smoking, focusing on preventive factors against atherosclerosis, increasing dietary intake of fresh fruits and vegetables, and supplementing with nutritional and botanical antioxidants.

In particular, tobacco smoking greatly increases the risk of ARMD.⁵ Someone who smokes a pack of cigarettes a day for any significant length of time increases his or her risk for ARMD by two to three times that of someone who has never smoked.^5,⁶ This risk does not return to the control rate until after a person has stopped smoking for 15 years.⁶

There is also a strong genetic component to consider. Although a number of genetic markers have been identified, a family history may be the most convenient screening method. The lifetime risk of developing late-stage macular degeneration is 50% for people who have a relative with macular degeneration versus 12% for people who do not—a fourfold higher risk. Although genomic family scans of 364 families have revealed a region of chromosome 10 as possibly containing an association with ARMD,⁷ diversity in phenotype and the late onset of disease complicate the feasibility of linkage studies. Interestingly, higher birth weight and lower head circumference/birth weight ratio are associated with significantly higher risk.⁸

Reducing and Preventing Atherosclerosis

Although atherosclerosis is now a well-accepted risk factor for macular degeneration, this association was unconfirmed until 1995.⁹ In the confirmation study, 104 subjects with and 1324 subjects without macular degeneration were evaluated for atherosclerosis via ultrasonographic determination of the intimal-medial thickness, assessed for the presence of atherosclerotic plaque in the carotid arteries, and measured for the ankle/arm systolic blood pressure ratio (an indicator of peripheral atherosclerosis). The results indicated that in subjects younger than 85 years, plaques in the carotid bifurcation were associated with a 4.7 times higher prevalence of macular degeneration. Lower extremity atherosclerosis was associated with a 2.5 times greater risk. These results indicated that measures designed to reduce the risk of atherosclerosis are of great significance in the prevention and treatment of macular degeneration (see Chapter 148 for a comprehensive program for prevention and reversal).

Diet

A number of dietary factors are important. Not surprisingly, these mirror those dietary factors that prevent other chronic degenerative diseases, including atherosclerosis. A diet rich in fruits and vegetables is associated with a lower risk for ARMD. Presumably this protection is the result of a greater intake of antioxidant vitamins and minerals.¹⁰^–¹² However, various “nonessential” food components—such as flavonoids and the non–provitamin A carotenes lutein, zeaxanthin, and lycopene—are proving to be even more significant in protecting against ARMD than traditional nutritional antioxidants (e.g., vitamins C and E, zinc, and selenium). The macula, especially its central portion, the fovea, owes its yellow color to its high concentration of lutein and zeaxanthin. These yellow carotenoids function in preventing oxidative damage to the area of the retina responsible for fine vision and obviously have a central role in protecting against the development of macular degeneration.^13,¹⁴

The carotene lycopene, a component of tomatoes and other red fruits and vegetables, is also protective. In one study, individuals with lycopene content in the lowest quintile were twice as likely to have ARMD.¹²

Moderate wine consumption is also associated with a decreased risk of ARMD.¹⁵ Red wine contains anthocyanins, powerful antioxidants that are probably responsible for the protective effect. It is important to note that beer consumption increased the accumulation of drusen and the risk of exudative macular disease¹⁶ and therefore should be avoided.

Just as in atherosclerosis, the type of dietary fat appears to play a role in ARMD. A cohort study of 261 individuals with early or intermediate stages of ARMD revealed a twofold increased risk of progression with a high intake of animal fats and processed baked goods. In contrast, higher fish and nut intakes were associated with a lower risk of ARMD progression.¹⁷ The intake of long-chain omega-3 fatty acids reduces the incidence of ARMD and was shown to be inversely associated with the 12-year progression to ARMD.¹⁸^–²⁰

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