Macular degeneration is of two types; they are dry and wet macular degeneration. Dry macular degeneration type is the most common one.
Type of Macular degeneration
- Dry macular degeneration
- Wet macular degeneration
It is possible for a person to suffer from both forms, affecting one or both eyes, and it progresses slowly or rapidly. Dry macular degeneration may progress to cause vision loss without changing into the wet-form. However, it is also possible for the early stage of macular degeneration of dry-form to change into the wet form when advances. Macular degeneration is the leading cause of vision loss in people over 60 years of age.
Dry Macular Degeneration
It is the most common type diagnosed in 85-90 percent of cases, in which the photosensitive cells of the macula slowly break down. Extra-cellular waste products of metabolism “Drusen” is a yellow deposit, forms under the retina between the retinal-pigmented epithelium (RPE) layer and the Bruch's membrane. Drusen is often finding in the eyes of aged people, but an increased size or number is the first sign of macular degeneration. Over time, drusen is associated with macula deterioration and the death of RPE and photoreceptor cells, causing blurred or spotty vision. This macular degeneration does not cause any pain, but in its early stages, there may be a slightly blurry vision. However, as more and more of the cells die, central vision worsens over time. In severe cases can cause profound vision loss, affecting the quality of life.
The dry form of macular degeneration has three stages:
- Early - patients have many small drusen or a few medium-sized drusen. There is no vision loss or any other symptoms at this stage.
- Intermediate - patients have many medium-sized drusen or few large drusen. They need bright light for reading, blur spot may appear in the visual field.
- Advanced - patients have a large number and/or size of drusen deposits, and breakdown of RPE, photoreceptor cells, and Bruch membrane. Blurry spot occurs in the center of the visual field and can become larger and darker, gradually causing a complete loss of central vision.
Wet Macular Degeneration
It is a rare form of macular degeneration accounts for approximately 10% of the cases of age-related macula degeneration, but results in 90% of the cases of legal blindness. It develops, when abnormal blood vessels grow behind the macula as RPE and photoreceptor cells die. The Bruch’s membrane begins to break down near drusen deposits, and new fragile blood vessels grow called neovascularization. That can leak fluid and blood, resulting in scarring of the macula and has the potential for rapid, severe damage. Straight vision can become poor or lost entirely in a short period, even within days or weeks. All wet macular degeneration is considering advanced stage.