A Common Disease of the Eye – Macular Degeneration Causes Central Vision Loss

Age-Related Vision Loss

It used to be assumed that vision deteriorated as a normal part of the aging process. Research has now confirmed that this age-related vision loss is tied to a particular disease of the retina called Macular Degeneration. This disease is both chronic and progressive affecting:

  • Central vision
  • Sharpness of vision
  • Colour recognition
  • Contrast recognition

Research has proven that this disease is treatable and the progression can be halted when it is discovered at the early stages. Macular degeneration is currently the leading cause of blindness and vision loss in people over the age of 50 in North America.

If left untreated macular degeneration leads to blind spots and in some cases a complete loss of central vision. Getting regular eye examinations and periodically looking at an Amsler Grid are the best ways to detect the early stages of this disease.

The Macula

In order to understand how Age-Related Macular Degeneration (AMD) causes vision loss, it is important to understand how the eye controls central vision. The retina is responsible for taking the light that comes into the eye and transforming it into electronic impulses that are then sent to the brain to be interpreted.

The area of the retina responsible for central vision is called the macula. The macula is made up on densely positioned photoreceptors called cone cells that also control the sharpness of vision.

There is a layer of the macula called the retinal pigment epithelium that shields the retina from excessive light coming in. Macular pigment is made up of plant-based carotenoids that are known to protect the eye from harmful blue light and free radicals.

Dry – Macular Degeneration Causes

Dry AMD is characterized by a thinning of the retinal pigment epithelium. This is usually attributed to the aging process, but other factors can cause this layer to prematurely thin. As this layer becomes thin, its ability to prevent extra light from coming into the retina is compromised resulting in images being blurred and distorted.

The symptoms can be very subtle and hard to notice until the disease is in its advanced stages. Loss of vision is usually very gradual and progressive. This type of macular degeneration accounts for approximately 90% of all reported cases.

Supplement therapy of the three carotenoids (Lutein, Zeaxanthin and Meso-Zeaxanthin) found in macular pigment has been successfully used to raise the levels of macular pigment in the eye. This type of therapy has been proven to help stop the progression of dry AMD and there are reports of it helping individuals regain portions of lost vision.

Wet – Macular Degeneration Causes

Wet AMD is caused by more invasive and destructive means. This disease is caused when fragile blood vessels grow abnormally beneath the macula. These blood vessels are prone to leaking blood and other fluids onto the macula.

As these fluids dry, they can destroy the photoreceptor cone cells and cause scarring. This scarring is what causes large blind spots to develop and the rapid reduction of sharp and central vision.

The treatments for wet AMD are much more invasive as well. Common treatments involve using lasers to seal the leaking blood vessels or injecting a chemical into the eye that can slow the progression of the disease.