By Dr. George J. Ko
For Northwest Asian Weekly
Age-related macular degeneration (AMD) is the leading cause of vision loss in the United States. It involves damage to the macula, which is the light-sensing tissue in the eye located at the center of the retina.
There are two common types of AMD: dry AMD, which comprises 85 percent of the cases. It can cause gradual progressive, central visual loss through an inflammatory and degenerative process.
The remaining cases are of wet AMD, which usually leads to more acute vision loss with the abnormal growth of blood vessels that leak and bleed.
Much of our past understanding of AMD came from studies in white and Black populations. It was not until this past decade that studies in Asian countries shed light on the importance of AMD and low vision among Asians.
Though not the leading cause, AMD is a major cause of visual impairment for individuals 50 years and older in Asian countries. The number is growing significantly, possibly due to the Westernization of lifestyles.
The impression many people previously had of AMD being a much less common problem in the Asian population than in the white population is no longer true.
Studies in Japan, Taiwan, Singapore, and China have suggested that the prevalence of AMD in Asians may not be very different from that in the white population. The Shihpai Eye Study in Taiwan showed that retinal diseases, which include AMD, together are the leading cause of blindness. In the Multiethnic Study of Atherosclerosis in the United States, it was noted that the overall prevalence of AMD was close between the white population and the Chinese population. Wet AMD was even more common in Chinese subjects than white subjects.
If experiencing vision loss, individuals need to see a retina specialist.
The Amsler grid is a diagnostic tool that one can use at home for detection of visual disturbances caused by changes in the macula.
To use the Amsler grid:
1. Wear your reading glasses and hold the grid 12 to 15 inches away from your face with good lighting.
2. Cover one eye.
3. Look directly at the center dot with the uncovered eye.
4. While looking directly at the center dot, note whether the lines of the grid are straight or if any areas are distorted, blurred, or dark.
5. Repeat this procedure with the other eye.
See your eye care provider right away if:
• Straight lines appear wavy on the Amsler grid.
• You have difficulty seeing at a distance.
• You have a decreased ability in distinguishing colors.
• You have an inability to see details, such as people’s faces or words in a book.
• There are dark or empty spots that block the center of your vision.
A thorough retinal exam may be needed if any of the above is true.
It is proven that nutritional supplements are beneficial for certain patients with dry AMD. There are also prompt treatments to improve vision like anti-vascular endothelial growth factor for patients with wet AMD. Low vision resources are also available to improve quality of life.
Research continues for AMD treatments, and we’ll see increasingly effective treatments becoming available in the very near future. Other experimental treatments like the insertion of a “retinal chip,” which may restore vision loss, are also currently being investigated.
Early detection and treatment is the best defense against losing your vision.
As part of Age-Related Macular Degeneration/Low Vision Awareness Month in March, I urge local residents to be screened for age-related vision problems by having regular eye exams and talking with their primary eye care provider. ♦
George J. Ko is a Board-certified ophthalmologist specializing in the diseases and surgery of the retina. His practice, Retina Institute of Washington, is located diagonally from Valley Medical Center at Valley Medical Dental Center, 4300 Talbot Rd. S., Suite 201, Renton, WA 98055. He is fluent in Chinese. Call 425-228-6262 or visit www.retinainstitutewa.com for more information or to make an appointment.
Ko can be contacted at email@example.com.